Author Archives: Anna Hindley


EWI Pro Renders: The Ultimate Guide

Thin Coat Renders

EWI Pro’s thin coat render range is highly customisable. Customers can choose the render that offers the most suitable benefits for their property; for example crack resistance or self cleaning capabilities. Each of our thin coat renders can also be tinted to create any colour – this includes RAL and NCS colours – and they each come in a variety of different grain sizes to achieve different levels of texture depending upon preference. Thin coat render technology is known for being flexible and crack resistance, so it’s a real customer favourite!

Premium Bio Silicone Render

The Premium Bio Silicone render is our top of the line, breathable thin coat render, offering advanced self cleaning capabilities, enhanced impact resistance and increased UV protection.  This means that it provides a long-lasting, crack resistant finish that will remain vibrant in colour for years to come.

Silicone Render

Silicone render is a notoriously high performance render. It offers breathability, crack resistance and self cleaning capabilities. It’s a very popular choice for customers as it is commonly associated with coloured render.

Silicone Silicate Render

Silicone Silicate is a hybrid silicone render. It’s highly versatile but also great value, offering the key benefit of breathability. While it does possess less self cleaning capabilities than our full Silicone render and our Premium Bio Silicone render, Silicone Silicate does offer a long-lasting, aesthetically pleasing finish.

Acrylic Render

Acrylic render is highly impact resistant, and is known for being particularly resistant to UV (it retains the colour pigment and therefore does not fade over time). It’s a well-known render as although it lacks the breathability of the silicones it is trustworthy and long lasting.

Mineral Render

Our one and only dry-mix render, the Mineral Render requires mixing with water before application. It’s fast-drying and is therefore ideally used in cold-climate conditions and for winter installations. It comes with the same option of grain sizes, however Mineral Render does require painting with Silicone Paint afterwards to achieve a decorative finish and provide a waterproof barrier.

Thick Coat Renders

Our thick coat renders are ideal if a traditional finish is what you’re looking for. As the name implies, they are applied in a thicker layer and achieve a different surface effect than our thin coat renders.

Monocouche Scratch Render

Monocouche Scratch Render is a dry-mix, polymer modified, one coat render. It is applied at an approximate thickness of around 16mm, before it is left to set and then scratched back 2mm. The Monocouche provides a chalky, sandstone effect with a dappled surface.

And there you have it! The complete guide to EWI Pro renders. If you have any further questions or are wondering which one may be best for your specific property, then feel free to give our sales team a call!

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applying render to thoma holz 100

Applying Render to Thoma Holz 100

This week in our ‘applying render to’ blog series, we’re discussing the best method for applying render to a Thoma Holz 100 construction.

Thoma Holz 100 is a solid wood building material that combines modern building technologies with the traditional; it creates an eco friendly, natural and sustainable construction that offers numerous benefits, some of which include:

  • Breathability and airtightness
  • Fire safety
  • Soundproofing
  • Quick assembly time
  • Eco-friendly (sustainable timber)
  • Excellent indoor air quality
  • Naturally high thermal performance

Thoma Holz 100 is a truly high performance building material, and the wood effect is definitely a pleasing look. However, if you wanted to mix it up a bit then applying render to Thoma Holz 100 is very easy.

How to Render Thoma Holz 100

The only downside to using solid wood construction is that wet, cementitious materials are unsuitable for application directly onto the surface of the wood. This is because Thoma Holz 100 is a dry construction, so any water within the render materials can be absorbed into the wood, thereby affecting the structure. Instead, the solution is to install either render carrier board (which is a bit of a pain to fix) or Wood Fibre insulation on top of the Thoma Holz 100, before finally applying the render!

The benefit of using Wood Fibre instead of render carrier board is that it has excellent thermal properties, improving the performance of the building but also complimenting the structure. Timber blocks and timber insulation boards work well together – no? The Wood Fibre insulation boards that we offer are also extremely sustainable (they’re by Pavatex and are NaturePlus certified!), so if maintaining sustainability is a concern then Wood Fibre is the way to go.

To secure the Wood Fibre insulation to the Thoma Holz 100, simply use stainless steel wood screws with universal fixing discs – no adhesive should be used as this is a dry-fix system. The Wood Fibre boards lock together, so the risk of thermal bridging is thoroughly reduced; they’re also really breathable and therefore will not hinder the breathability of the Thoma Holz 100.

Once the insulation boards have been applied, the Premium Basecoat should be applied directly on top of the insulation boards, and a fibreglass mesh should be embedded within it. We recommend using a breathable thin coat render such as our Silicone Render, which needs to be applied on top of the Premium Basecoat once it has fully set. The render can be tinted to create any colour and comes in a range of grain sizes, so the design options are endless!

Want to read more from our ‘applying render to…’ series?

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mineral wool sheathing board

How to fix Mineral Wool to Sheathing Board

Fixing Mineral Wool to sheathing board, or even insulating sheathing board in general can be a bit tricky. Ventilated cavities or no ventilated cavities? Render carrier board onto battens or no render carrier board onto battens? The list of options goes on, hence why so many people seem to avoid working with these systems.

Well, at EWI Store we’re going to tackle the subject and make it nice and easy; if you’re going to be insulating a sheathing board substrate then the easiest thing to do is stick some Mineral Wool on and render over it. So without further ado here’s our how-to guide…

Preparing the Sheathing Board

Whether it’s a timber frame or a steel frame, the sheathing board needs to be a prepared in the same way. It’s imperative to use a joint tape to secure all the joints between the sheathing boards together; this essentially improves how weathertight the system is and protects against condensation gathering between the gaps.

We recommend using a breathable joint tape such as the Pavatex ‘Pavafix Win’ tape; this is a self-adhesive breather membrane that is incredibly easy to apply.

Sheathing board typically doesn’t need priming, so you are free to skip this stage altogether and go straight to fixing the Mineral Wool insulation.

Fixing the Mineral Wool to the Sheathing Board

When insulating directly onto sheathing board, the EWI-225 Premium Basecoat should be used. This can be applied to the back of the insulation boards to secure them to the substrate, then stainless steel self-drilling screws with universal fixing discs should be used as a secondary method of securing the insulation.

Applying Render to the Insulated Sheathing Board

Rendering the Mineral Wool involves applying a basecoat layer of the Premium Basecoat to the insulation boards, before embedding strips of fibreglass mesh within the basecoat. Don’t forget that each strip of mesh should overlap by 10cm!

The basecoat needs to be left to dry, and then it should be primed with the appropriate render primer – for example, you’d use our SiSi render primer with our Silicone Silicate render, so whatever render you are using the primer should match.

Once the primer has dried, you are then ready to render. Apply your render of choice to the substrate using a plastering trowel; if you are using our thin coat renders then the thickness that the render is meant to applied at should match the grain size you have chosen.

And there you have it! Applying Mineral Wool to sheathing board is a really easy way to not only get the render finish that you want, but also improve the thermal performance of the whole building structure.

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lightweight render system

What is a Lightweight Render system?

Lightweight render systems have grown in popularity in recent years due to increased awareness of the disadvantages of sand and cement render. Lightweight render systems are ideal for circumstances where the substrate requires either vapour permeability or flexibility; this is because these systems tend to contain lime, which offers both of these characteristics.

Lightweight render systems differ from sand and cement systems due to the fact that they typically consist of far more components and are much less likely to crack and wither away. Sand and cement renders are notoriously bulky, unforgiving and unbreathable. They tend to have a poor reputation for being unreliable and prone to cracking, so people turn to thin coat render systems and lightweight render systems for an ideal solution.

So what does a lightweight render system consist of? How do you install it and when would you install it? We’re going to be answering all of these questions in today’s blog post!

Components of a Lightweight Render System

In an EWI Pro lightweight render system, the components consist of an optional substrate primer; the Lightweight Basecoat; the Premium Basecoat; Fibreglass Mesh; a render primer and finally a through-coloured Silicone Render.

The key components that make this system ‘lightweight’ is the EWI-269 Lightweight Basecoat, which is a lime-based basecoat, with an air content of approximately 29% and a bulk density (once set) of approx 1.2 g/m3.  The Lightweight Basecoat binds gently to substrates, offering a level of flexibility that ensures crack resistance. The great thing about this basecoat is that it is highly versatile; it’s suitable for a wide range of substrates and works especially well on high performance blockwork.

The second component that enables the system to be lightweight is the thin coat Silicone Render. This is applied on top of the Lightweight Basecoat (details below) and because it’s so thin (it’s applied only a couple of millimetres thick) it is easily flexible and therefore is able to work well in conjunction with the Lightweight Basecoat.

We always recommend using a vapour permeable render on top of the Lightweight Basecoat so as not to hinder its permeability; a Silicone Render is perfect for this because it is very breathable so moisture can easily escape through its structure.

How to Install a Lightweight Render System

The method used when installing a lightweight render system generally depends on the substrate. So we’re going to outline the two main ways of applying the system:

  1. Applying the Lightweight Render System onto Ordinary Masonry

When applying a lightweight render system onto ordinary masonry, the substrate needs to be clean, dry and dust-free before any work is carried out. The substrate will also need priming with our Water Based Primer to reduce its absorptivity.

Once this has been carried out, the Lightweight Basecoat should be applied with either a trowel or a spray machine up to a thickness of 20mm. The Basecoat needs to be left to go off, before the Premium Basecoat is applied on top.

The reason we recommend applying an additional basecoat is because our Premium Basecoat is the strongest basecoat in our range; it’s vapour permeable and has strong adhesive capabilities. In the UK, the harsher weathers can have a damaging effect on softer materials, hence the repeated use of sand and cement render.

We suggest using the Premium Basecoat on top of the Lightweight Basecoat as a way of strengthening the system against the more challenging climate and to ensure an extra level of crack resistance. Fibreglass Mesh should also be embedded within the Premium Basecoat to enhance the tensile strength of the system; it’s all about building up compatible layers to achieve a sturdy finish.

The Premium Basecoat should be left to set entirely, and then the SiSi render primer should be painted on top and left to dry. All of the aforementioned layers are applied with the intention of levelling and strengthening the substrate; the final layer of the lightweight render system consists of the Silicone Render which is both decorative and functional.

The Silicone Render works well with both materials, allowing for movements within the building structure without cracking, while also enabling the system to breathe. The render is applied at a thickness that corresponds with the chosen grain size; if it’s a 1.5mm grain size then the render is applied at 1.5mm. It can be tinted to create any colour and contributes towards a long-lasting and incredibly durable render system.

  1. Applying Lightweight Render Systems to High Performance Blockwork

Applying this system to high performance blockwork is a little different because these types of blocks tend to be really absorptive and so the correct method of application is very necessary to ensure no cracks.

With a high performance substrate, you would forgo the priming stage and skip straight to applying the Lightweight Basecoat. The key difference, however, is in your method of application of the basecoat. It needs to be applied in two passes; the first pass should be applied at approximately two thirds of the total thickness – so around 12mm. Leave it to pull back slightly and then apply the final third.

Once both passes of the Lightweight Basecoat have set completely, you would apply the Premium Basecoat and follow the same process as outlined above.

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cracked render

Why does render crack?

Typically, render is used to provide the building fabric with protection against the elements while also providing an aesthetically pleasing finish. Often, a render is applied to cover up the use of cheaper building materials such as blockwork rather than brick and stonework.

Unfortunately, a common stereotype of render is that it is liable to experience cracking. This is a huge concern for many of our customers, who want to invest in a new render facade but don’t want to find that a few years (or even months) down the line their investment isn’t holding true to its promise.

Cracks are the effect of a number of underlying problems, and if left to their own devices they can escalate a situation from bad to worse by drawing water through the building. There are a number of reasons that render may crack, and in this blog post we’re going to be looking into these reasons.


First thing’s first, is your render really old? Render does in fact have a lifespan, especially sand and cement render. If you are living in a fairly old property that is rendered in sand and cement, cracking is going to be inevitable due to the effect of weathering.

When driving rain, snow, frost and more are constantly attacking the exterior of your building, it’s likely that you will experience some kind of negative impact. This is particularly true for sand and cement render, which is incredibly solid, unforgiving and prone to absorbing water. So, consider how old the property is and when it is likely that it was rendered – the age of the render may be the reason for the wear and tear.

Incorrect materials for the substrate

We’ve previously written about a case study where sand and cement render was applied to high performance blockwork, and the resulting finish was a cracked mess within weeks. The reason for the cracked render is that high performance blockwork (this includes Ziegel blocks, AAC, Thermalite etc.) tends to be very soft and malleable, while sand and cement is incredibly solid.

The phrase ‘opposites attract’ just isn’t true in the case of renders and substrates; when choosing a render for your property, it’s imperative that it compliments the substrate so that they will work in tandem. This could be the reason your render is cracking. An installer should be able to advise you on the best type of render for the building fabric.  

Poor quality of workmanship – poor sealing at junctures, incorrect movement joints

A good quality installation from a knowledgeable installer can make all the difference to the durability of your installation. A trusted installer will ensure that correct reinforcement is applied around the weaker areas of a structure, especially around movement joints and reveals.

The render needs to be able to replicate and compensate for movements within the underlying substrate, otherwise it will crack. If this has not been taken into consideration then this could be the cause of the cracks.  

The render dried out too fast

Most common with dry-mix renders, if the water evaporates from the material too quickly it doesn’t leave enough time for the render to bond properly and the surface colour can appear patchy and discoloured.

A render that has dried out too fast is a dehydrated, weak surface and cracking is therefore inevitable. To avoid this, the render needs to be applied in moderate temperatures and if possible away from the direct glare of the sun, and for dry-mix renders if the mixture appears to be drying too fast simply sprinkle it with water as needed.

Fibreglass mesh wasn’t used

Best practice for rendering is to embed fibreglass mesh within the basecoat layer. The mesh is applied in strips that are each overlapped, reinforcing the entire surface of the basecoat and increasing its tensile strength. The result of this is that any movements within the building fabric will be absorbed by the mesh.

If Fibreglass Mesh isn’t embedded within the basecoat or even in the first pass of render, unfortunately this could be a contributing factor towards the cracking.

Structural problems

Sometimes it’s not actually the fault of the render, it’s the effect of underlying structural problems that are making themselves known by damaging the render finish. The structural problems can be numerous and difficult to pin down, whether it’s differential movement between an extension and the main house or due to water and rust.

Rising damp

Rising damp is the fear of all property owners as it’s often difficult to catch and identify. It’s relatively rare, but rising damp is essentially when water travels from the ground up through the walls by capillary action, causing bulging in the walls and floor boards and general structural damage. The structural damage that rising damp can cause is what encourages cracks to form in the external render. You will most likely notice signs of rising damp not just in your render but internally as well, so if this is the case then it needs to be identified and rectified immediately.

Leave a comment down below if you’ve experienced cracking in your render and how you fixed the problem!

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brick slips insulation board

How to use Brick Slips on Insulation Board

Brick slips are an incredibly versatile material, allowing users to realistically recreate a brick effect after applying insulation board to the building. Some people want the benefits of the external wall insulation without losing the classic brick look of their property, which is why brick slips are such a great solution.

Brick slips are also excellent if you are living in an area where where is a high risk of mechanical impact, for example next to a busy road; they have a greater ability with withstand damage and are generally more hard wearing. Our brick slips are highly flexible (you can bend them around corners!) and come in a wide range of attractive, natural colours.

So without further ado, here is how to use brick slips on external insulation board!

Applying Brick Slips to EPS Insulation Board

EPS insulation board is a classic when it comes to external wall insulation. It’s cost effective and has excellent thermal capabilities, while also being incredibly easy to work with. EPS comes in a huge range of thicknesses, depending on how much you want to improve the thermal performance of your property (the thicker the insulation the better the insulator).

Applying brick slips to EPS is incredibly easy. The EPS boards are secured to the substrate using our EWI-220 EPS Basecoat Adhesive with plastic fixings. Once dry, the EWI-220 is used again to form the basecoat layer on top of the insulation boards. Fibreglass Mesh is sunk within the basecoat to enhance the tensile strength of the whole system, and then once a smooth surface has been achieve the basecoat is left to dry before the brick slips can be applied!

To apply the brick slips, you would use our special ready-to-use brick slip adhesive which comes in a wide range of colours for a customisable finish. The adhesive dries quickly so we recommend applying it with a notched trowel 1m2 at a time to give plenty of time to stick the brick slips on neatly.

Applying Brick Slips to Mineral Wool Insulation Board

Mineral Wool insulation is a premium insulating material. It’s class A1 non-combustible, which means it actually works to prevent the spread of flames. It’s also a vapour permeable material so will actively allow moisture to escape from the building fabric.

Mineral Wool is heavier than EPS and therefore requires a stronger adhesive and metal mechanical fixings. We recommend using our EWI-225 Premium Basecoat which is a dual purpose product, suitable as both an adhesive and a basecoat.

After the Fibreglass Mesh has been embedded within the basecoat, the brick slips can be applied in the same way you would with EPS. Simply apply the brick slip adhesive using a notched trowel to an area of 1m2, applying the brick slips as you go.

And there you have it! Applying brick slips may be slightly more time consuming to apply than a coloured render, but they do achieve a really realistic finish.

Stay tuned for more content! We upload a new blog post every Tuesday and Thursday, so keep up to date. We also release a weekly newsletter which hands out exclusive special offers and discount codes so sign up to that as well.

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applying render to SIPS

Applying Render to SIPS Panels

Structural Insulated Panels (SIPs) are a high performance building material consisting of an insulating foam core, sandwiched between two panels of OSB board. There are many benefits to building with SIPs panels, including insulation and airtightness. With SIPs panels, the insulation is highly effective due to the fact that the panels fit together tightly enough that air leakages are minimised. They’re a popular building material because the required U-values to meet building regulations can easily be achieved with a very quick speed of build.

Rendering SIPs panels can pose a bit of a challenge due to the fact that the render cannot be applied to the OSB board directly. In order to be able to render the SIPs there are various steps that need to be undertaken before the rendering can go ahead.

Installing Timber Battens onto the SIPs Panels

The very first step in applying render to SIPs panels a breather membrane needs to be secured to the external OSB panels with galvanised staples at 600mm centres horizontally and 300mm centres vertically. We recommend using the Dupont Tyvek Housewrap, as this membrane is totally vapour permeable and can be left exposed for up to four months.

Once the breather membrane has been applied, vertical timber battens need to be installed onto the SIPs panels. These are installed as a means of supporting the render carrier board which is secured to the battens, and so the size of your render carrier board will dictate where you position the battens. Once the battens are in place, you can secure the render carrier board to them using the appropriate wood screws.

The render carrier boards should have a slight gap of 3-5mm between each board. This needs to be covered over using Pavatex Render Carrier Board Joint Tape, which is another breathable membrane except this one is a self-adhesive tape and is designed for the purpose of jointing render carrier boards before render is applied directly on top. The joint tape will further secure the boards and prevent the wet materials seeping through the gaps.

Thin Coat Render Systems on SIPs

We recommend using the Premium Basecoat for rendering SIPs as this is our strongest basecoat and will therefore ensure the system is highly secure and crack-resistant (read about how to fix cracked render here). We always recommend that Fibreglass Mesh is embedded within the basecoat as a means of increasing the tensile strength of the system; each strip of mesh is overlapped by 10-15cm all the way around, and therefore once the basecoat is set the mesh should absorb any movements within the render carrier boards without cracking.

After the basecoat has set for 24-48 hours, a render primer needs to be applied. The primer used will depend upon which kind of render you are using, so if you’re going for an Acrylic Render you will use our Mineral and Acrylic Primer, but the silicone-based renders require the SiSi Render Primer. This can be painted onto the basecoat and left to dry for 12 hours, and then finally you are ready to render!

Achieving a nice render finish on SIPs depends upon thorough preparation, so by now you should have a perfectly stable and flat basecoat that will provide the perfect surface for the thin coat render. The render is applied in such a thin layer (the thickness that you apply the render matches the grain size) that any large imperfections can be quite apparent, particularly if you’ve gone for a smaller grain size i.e. 1mm. Our most popular choice for installers is our Silicone Silicate Render in a 1.5mm grain size because it is breathable and offers good coverage at a price that is great value.

The render should be applied using a notched trowel, and then it should be rubbed up using a plastic render float to bring out the texture. Once applied, leave it to set for 24-48 hours.

Wood Fibre Insulation onto SIPS Panels

If render carrier board onto battens seems like too much hassle for you, then why not use Wood Fibre insulation? The Wood Fibre can be attached directly to the SIPS panels using stainless steel wood screws and universal fixing discs. After this, you simply apply the thin coat render system on top as explained above. Not only is this a simple and easy way of doing it, it reduces the risk of condensation and also improves the thermal efficiency of the structure.

And there you have it; how to apply render to SIPs panels. We have also covered how you might go about applying render to other types of substrates, including ICF and high performance blockwork. So check out those blog posts and stay tuned for future content!

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render coverage

Render Coverage: The Ultimate Guide

When ordering materials online, customers are often unsure as to the quantities that they will require for the approximate square meterage they are working on. So, we’ve put together a guide to EWI Pro render coverage to make things more clear!

Coloured Render Coverage

Our coloured renders all come in a variety of grain sizes. This means that the grain size will determine how much coverage you’ll get out of a 25kg bucket. Bear in mind that these numbers may vary slightly depending on application; for example if you drop/lose relatively little product then you will get more out of the bucket. Coverage for our Premium Bio SiliconeSilicone, Silicone Silicate and Acrylic renders are as follows…

1mm Grain Size – 10m2

1.5mm Grain Size – 7-10m2

2mm Grain Size – 6-7m2

3mm Grain Size – 5-6m2

Monocouche Render Coverage

Monocouche render is a dry-mix render, so the coverage can vary depending upon how thick you apply it and how much water you mix in. The following coverage is therefore based upon applying the Monocouche render at a total thickness of 18mm before scratching back (two passes):

1 x 25kg bag – 1m2

Mineral Render Coverage

Mineral render is also a dry-mix render, however this is thin coat. One bag will therefore stretch between 8-10m2 depending upon application and the thickness that it is applied at. Mineral render does however need painting over with Silicone paint; one bucket of Silicone paint (15L) will cover 60-70m2.

Basecoats Coverage

Basecoats especially can be a tricky thing to calculate. Because the majority of our basecoats are multi-purpose and are used as both an adhesive and a basecoat, the coverage can vary:

Adhesion and basecoat – 2.8m2

Basecoat for rendering only – 4.5m2                                                                                                                                  


Substrate Primers

Substrate primers are applied directly to the substrate (be it brick, block or other) before any other materials are applied. Coverage of the primers is hard to estimate as certain substrates are more absorptive than others; for example if you are rendering a particularly dry substrate. Coverage for substrate primers are as follows:

Water Based Primer (5L) – 15-30m2 depending upon the absorptive capacity of the substrate

Universal Primer (20kg) – 50-70m2 depending upon the absorptive capacity of the substrate

Render Primers

Render primers are applied on top of the basecoat before the render itself is applied. These help to create a vibrancy of colour and strong adhesion to the basecoat. We have three main types of render primer, the Acrylic & Mineral Primer and Silicone Silicate Render Primer. Coverage for these is as follows:

7L bucket – 20m2

21L bucket – 60-70m2

And there you have it! Our ultimate guide to materials coverage. We hope this was useful! Keep a lookout for our latest blog posts – we upload every Tuesday and Thursday!

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rendering plywood

Applying Render to Plywood

We recently had an interesting enquiry from a customer about how you would go about rendering plywood. It’s a tricky question, because plywood really isn’t an ideal substrate to render onto, however sometimes it’s unavoidable. There are solutions for applying render to plywood, and we’re going to talk you through the best way you can do this!

Rendering Plywood: Render Carrier Board

When rendering any substrate, especially when rendering plywood, consideration needs to be taken as to the suitability of the substrate for the materials that you are using. Plywood is not particularly waterproof and will inevitably absorb water from the basecoat, which can cause the wood to warp and therefore hinder structural integrity.

To avoid this, render carrier board is an ideal solution, but the downside is that it can’t be applied directly on top of the plywood. This is because the fabrics need ventilation to allow moisture to escape and to avoid a situation where water builds up between the two materials; an air gap between the two is needed for the reduction of condensation. To resolve this, the best course of action is to staple a breather membrane to the substrate, before installing timber battens on top of the ply; the positioning of the battens will depend upon the size of the render carrier board you are using.

Once these are in place, you can secure the render carrier boards on top of the battens and attach them with wood screws. The spacing of the boards will depend on the type of render carrier board you are using, however generally you would leave 4-5mm between each board. After the boards are in place, the gaps between them need to be covered over by a render carrier board tape; we tend to recommend the Pavatex render carrier board joint tape because it’s basically an extremely breathable self-adhesive membrane which prevents water vapour from gathering in between these gaps.

Basecoating the Render Carrier Boards

Render carrier boards don’t require priming because they are specially designed for being rendered, so you can go straight into applying the basecoat with no problems. Although it is possible to use the 220 Basecoat Adhesive, we recommend using the 225 Premium Basecoat as a basecoat for extra strength and breathability. At this stage, the necessary beading required for the structure is sunk into the basecoat along with fibreglass mesh – remember to overlap each strip of fibreglass mesh by about 10-15cm.

Once set for a period of 24-48 hours, the basecoat needs priming before rendering. The type of primer you use will depend upon the type of render; for example if you were to render using Silicone Render (we recommend this one for constructions that require a high level of breathability), you would need to use our SiSi Render Primer. This can be painted on and then left to dry for 12 hours.

Rendering the Basecoat Layer

After all of that essential preparation, you are finally ready to render. Using our ready-to-use Silicone Render, apply it to the substrate using a trowel at a thickness that matches the grain size of the render; for example, if you’ve chosen a 1.5mm grain size finish then you should apply the render at 1.5mm thick.

Once applied, rub up the surface of the render with a plastic render float to bring out the texture and achieve a consistent finish, then leave to dry for 24-48 hours.

We upload blog posts every Tuesday and Thursday, so stay tuned for more content.

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rendering metsec steel frame

Applying Render to Metsec Steel Frames

When it comes to rendering Metsec steel frame buildings, the external surface of the building needs to be taken into consideration. At EWI Store, we provide coloured render and external solutions for a wide range of substrates, and today we’re going to be discussing in detail the exact process of how to go about rendering a Metsec frame. Metsec is a company that sells cold-rolled steel for structural frames; essentially the building is constructed of a lightweight steel frame (produced by Metsec) and a variety of materials are anchored to the frame to create the buildings’ exterior skin.

There are many materials that can be used for the outside of the Metsec frame, but typically a sheathing board is secured to the steel frame. For non-residential buildings, Mineral Wool insulation is fixed to the sheathing board and the thin coat render system is applied on top. For residential projects, Mineral Wool insulation is installed within a cavity, before a render carrier board is secured to the steel frame on the outside. Quite often you can find steel frame buildings with a brick cladding forming the exterior surface as well.

We’re going to be taking a look into how you can render different substrates on a steel frame building!

Render Carrier Board: Rendering Metsec 

Once the render carrier boards have been secured to the steel battens, there will be a spacer gap of a few millimetres between each edge of the board. This is to give the boards space for ventilation and to compensate for any movement. However, these gaps need to be covered over using an appropriate render tape, or Pavatex Render Carrier Board Joint Tape; both are suitable, however the Pavatex tape acts as a vapour permeable membrane so has that extra level of breathability.

After you’ve joined the render carrier boards together using either of these methods, you can apply the EWI-225 Premium Basecoat to the surface of the render carrier board – no primer needed. Premium Basecoat is our strongest basecoat-adhesive, so we really advise using this as a basecoat for a secure render installation. The Premium Adhesive needs to be mixed with 6.5L of water and applied at a thickness of 6-8mm, before Fibreglass Mesh is embedded within the basecoat using the flat edge of the notched trowel. Each strip of Fibreglass Mesh should overlap its neighbouring strip by approximately 10-15cm.

Leave the basecoat to set for 24-48 hours, then prime the basecoat using an EWI Pro render primer. If you’re using our Silicone Silicate Render then the SiSi Render Primer is the ideal primer; simply paint it onto the basecoat and leave it to dry for 12 hours. After this, you are ready to apply your Silicone Silicate Render; this is the final layer that ensures the system is entirely waterproof and resistant to weathering. You can apply the Silicone Silicate render straight out of the bucket and trowel it on at a thickness that corresponds with the grain size; after this, rub up the surface of the render using a plastic render float to get a textured effect.

External Insulation: Rendering Metsec 

When rendering Metsec, architects will often look to create an insulated render system using a Metsec steel frame building. With this kind of construction, sheathing board is applied to the lightweight steel frame leaving a ventilated cavity in front, and then a render carrier board.  Following the manufacturer’s guidelines insulation is applied to the render carrier board using the appropriate adhesive and mechanical fixings. Once the insulation is in place, the Premium Basecoat can be used once again as a basecoat, before priming and rendering using Silicone Render.

It is commonplace to install a ventilated cavity within these residential systems, as it is a requirement for several insurance companies, although they have recently come under criticism from the general public and within the industry itself since the Grenfell tragedy. We advocate the use of Econic boards and Rockwool Mineral Wool insulation in these circumstances because they are A1 fire rated and non-combustible.  Products such as the Dupont Tyvek Firecurb Housewrap can also be introduced for extra vapour permeability and fire resistance.

And there you have it, rendering Metsec steel frames! We upload a new blog post every Tuesday and Thursday, so stay tuned for more content.

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mosaic render

What is Mosaic Render?

Mosaic Render is a bit of a luxury render, offering unparalleled durability and splash resistance. Our Mosaic Render contains quartz aggregate and is therefore known for being strong, durable and waterproof. This makes it ideal for below the DPC, where impact resistance and splash proofing are essential.

Mosaic Render is available in white, black and grey and not only looks fantastic but serves an integral function within the render and EWI system, ensuring that water will not penetrate from the ground up.

Mosaic Render as a Decorative Feature

The finish that Mosaic Render achieves is especially attractive in that the effect is almost marbled due to the fact that it is highly granulated and varicoloured. Because the product offers such a uniquely appealing finish, it is popularly used as a decorative feature for various areas of the property.

The render would produce a fantastic finish around pillars, windows and doors and on garden walls. It would also look great as a feature wall next to swimming pools because of its resistance to water and its durability. The porch area is also a very common area that homeowners use Mosaic Render, as it creates a nice contrast with the main render as a backdrop. In effect, Mosaic Render is brilliant for those looking to create a unique external facade, with close attention to detailing and high quality features.

Mosaic Render for the DPC

Another very common use of Mosaic Render is for the DPC, where durability, waterproofing and impact resistance is essential. Ensuring that an external wall insulation system is watertight at DPC level is vital to continued performance and longevity, and for this purpose mosaic offers unparalleled performance. The DPC area is also prone to plant growth and splashback, which this render can withstand really well.  

For ensuring a strong DPC, we always recommend using XPS insulation boards (because they have a higher density and are less likely to absorb water). XPS should be secured to the substrate using our Premium Basecoat, which is extra strong and breathable (this is also used for the basecoat reinforcement layer), and finally finished with the Mosaic Render.

Mosaic Render vs. Acrylic Render

As discussed, Mosaic Render is known for being extremely durable, impact resistant and waterproof. However, we also often talk about how Acrylic Render is impact resistant – so what is the difference?

Acrylic Render is a thin coat coloured render, with grain sizes suspended within the solution which give it a textured effect and a seamless colour. By contrast, Mosaic Render is made up of lots of different coloured grains which give a completely different look, these grains also make it slightly more hardwearing and waterproof.

And there you have it! Everything you need to know about our Mosaic Render. We upload a new blog post every Tuesday and Thursday so stay tuned for more content.

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re-rendering with coloured render

Re-rendering with Coloured Render

We speak to hundreds of customers who are looking at re-rendering with a thin coat coloured render, and need a solution for their existing render. Often this is because the existing render is cracked and damaged with staining from plant life and general signs of weathering. Re-rendering the property with a coloured render can work wonders on giving it a facelift and improving the general aesthetics.

In a previous blog post, we discussed how to replace pebbledash with coloured render, however in this blog we’ll be taking a look at how you might want to go about replacing an existing sand and cement render with coloured render.

Re-rendering Sand and Cement Render with Coloured Render

As is often discussed here at EWI Store, sand and cement render is extremely prone to cracking and water ingress. In general, sand and cement render is just not a suitable material for the vast majority of buildings, especially older buildings and timber frame structures; and yet it is still so commonly used. With coloured render, you are guaranteed a flexible and strong render finish because unlike sand and cement render, coloured render is applied in an extremely thin layer which means it’s much less unforgiving.

Coloured render also gives you the option of choosing a breathable render, such as Silicone or Silicone Silicate, which prevents water ingress and water vapour build-up by allowing it to escape from the building through the external walls, where it can then evaporate off the surface of the render.   

When considering re-rendering with coloured render, the most ideal place to start is by removing your cement render. This can be a pretty difficult process, as cement render is such a tough material and removing it poses a risk to the underlying substrate. Nevertheless, this is most likely the best course of action to protect your property against structural damage because Cement Render is incredibly liable to water ingress.

Re-rendering: Do I Remove or Repair my Sand and Cement Render?

If you’re considering re-rendering with coloured render, then most likely this is because your existing render has cracks within the surface. Unfortunately, as soon as the cracks start to appear then water ingress will undoubtedly follow. If this is clearly the case and your render is beyond repair then it will need removing. Once you’ve removed the render, you may need to repair the underlying substrate before you can go ahead with the re-rendering job.

On the other hand, if the render is in good condition it may be best to simply go over the top of the existing render with a coloured render system. Your installer will need to assess for any hollow patches and areas where the damage is too excessive to safely re-render. If the existing render is damaged or cracked in any way, then sometime down the line your new render may start showing cracks or it may even start falling off the wall, so ensuring the substrate is stable is essential.

How to Repair Sand and Cement Render

Often, sand and cement render was applied to buildings as a means of covering up cheap brickwork and to give an expensive-looking finish. When cracks start to appear in your render, it’s important to repair them as soon as possible in order to prevent water ingress. As soon as water gets behind the render, the process of freezing and thawing will eventually escalate the problem – leading to timber decay, internal damp and render falling off the walls.

If removing your existing render just isn’t possible without causing excessive damage to the underlying substrate, you may be able to patch repair it before applying a coloured render on top. You can use the Levelling Mortar to patch repair your existing render, as this can be applied at a thickness of up to 50mm, creating a smooth and stable surface for your new coloured render.

If your render has come away from the wall in some places completely, you can fill this using the Levelling Mortar, but we do recommend that you are careful to ensure that the rest of the render is stable enough to support a new coloured render.

Applying coloured render on top of existing render

Once you’ve established that your existing render is safe enough to re-render with coloured render, you first need to prime the substrate with the Water Based Primer. This will limit the absorptive capacity of the underlying sand and cement render and prevent it from drawing water out of the basecoat and creating a waterlogged mess underneath.

After this, you can use the Premium Adhesive as a basecoat, with Fibreglass Mesh embedded within it; each strip of mesh should overlap by 10-15cm. The reason we recommend using the Premium Adhesive is because it is much stronger than any of our other basecoat adhesives and will ensure a stable adhesion to the underlying render. Leave the basecoat to set for 24-48 hours, then you are ready to apply your coloured render.

We recommend using a Silicone Render because it’s extremely hydrophobic and vapour permeable. This means that it will prevent water ingress while at the same time allowing trapped water vapour to escape from its surface. It’s an ideal choice for old and new buildings as it’s extremely flexible so will not crack due to structural fluctuations.

And there you have it! How to re-render with coloured render. If you have any further questions or need advice about whether your property is suitable for re-rendering with coloured render, you can call our technical team who have all the technical know-how.

We upload a new blog post every Tuesday and Thursday, so stay tuned for more content!

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winter insulation materials

Winter Insulation Materials with EWI Store

Winter insulation materials… is your home prepared for winter?

Winter insulation materials are on everyone’s mind; these crisp and chilly mornings are a sure sign that the blazing heatwave of summer is over, and the dreaded task of defrosting the car every morning is drawing near. This time of year generally triggers a mass panic about where to buy winter insulation materials in order to prepare for winter, and we’re here to alleviate these stresses.

What is the solution to preparing homes for winter?

The answer to the above question is simply another question: is your home adequately insulated? If not, we’ve got everything you need. Below is an infographic all about heat loss in the home, and how external wall insulation can help.

Why choose EWI for your home?

  • Warmer in the winter
  • Cooler in the summer
  • Reduced damp
  • Reduced noise
  • Minimise energy bills
  • Extends the life of the property
  • Saves internal space

Install external wall insulation before Winter really sets in…

The best time to install external wall insulation is at this time of year, where the air temperatures are dropping but not yet freezing. EWI materials need to be used at the correct temperatures; this varies between manufacturers, but EWI Pro specify that most of their materials should be used between 5°C and 25°C. Autumn is therefore ideal for those last-minute preparations, and the good thing is that external wall insulation should only take a couple of weeks to install.

Insulating your home in the Winter? Use the right materials…

If you do happen to get to winter and discover that your insulation just isn’t enough, then it’s not too late! We have a range of winter insulation materials for installers to use during the winter months.

Winter Adhesive

Time to crack out the old Winter Adhesive. If you’re installing EPS insulation during the winter months then the Winter Adhesive is the perfect solution. It’s essentially the same as the EWI-220 EPS adhesive but it dries far quicker and is designed to be used even down to zero degrees. The Winter Adhesive is actually a bit of a lifesaver during colder climates, because it alleviates any worries about adhesive failure and resulting insulation falling off the wall.

Mineral Render

Mineral Render is a dry-mix render, so it’s in its nature to be more fast-drying. Mineral Render is intended for use in harsher climates, so it’s ideal for winter installations. It’s a thin coat render and is highly breathable, so you still get the same benefits of our other thin coat renders, the only downside is that because it’s a dry-mix it does require painting afterwards with a Silicone Paint.

Render Accelerator

If the idea of the Mineral Render really doesn’t appeal and a through-coloured render is what you want, then the Render Accelerator is the perfect solution. All you have to do is mix 200ml of the render accelerator into a 25kg tub of one of our thin coat renders, and it will speed up the drying times of the render.

The reason for render failure during colder temperatures is that it takes longer to dry and therefore water ingress becomes a problem. The accelerator completely reduces all of these worries, allowing you to install any EWI Pro thin coat render during the winter months.

Why is a fresh coat of render the best thing to have for winter?

Winter in the UK generally means miserable rain, wind and frost. Cycles of freezing and thawing can be seriously detrimental to building structures, especially if your home has an old, cracking sand and cement render. All it takes for a sand and cement render to fail is this process of freezing and thawing.

Water is easily drawn into cracks within the render before repeatedly freezing and thawing. This weakens the render and eventually, the sand and cement will fail and crumble away, leaving your wall exposed and unprotected against the elements. Worse yet is when water becomes trapped behind the non-breathable sand and cement render, moving through the walls to create damp patches internally.

A fresh coat of render installed before the temperatures really start to drop can save so much hassle. We recommend choosing a Silicone-based render, because they are extremely hydrophobic but also incredibly breathable; this means that water will not be absorbed into the render but any water vapour from inside the house can easily pass through. Silicone renders are also highly flexible, so cracking is very unlikely.

Looking for a trusted installer?

We know how hard it can be to find a responsible and reliable installer to carry out your renovation project, that’s why we have installers up and down the country who have been ‘EWI Pro approved.’ Fill out the contact form below and we will be in touch!

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coloured render vs. coloured paint

Coloured Render vs. Coloured Paint

When thinking about redecorating the exterior of your property, coloured paint is often the first thing people think of as opposed to coloured render. In fact, many people aren’t aware of how the two differ. So which is better – coloured render or coloured paint? We’re going to take a look at both to determine which one is the best choice. If you’re looking for an indepth comparison, you can also check out our dedicated blog posts ‘The best masonry paint? Silicone paint’ and ‘What is Silicone Render?’ for full detail!

What is Coloured Render?

Coloured render is a fairly specific type of render. It goes by many names, whether it’s a thin coat render, silicone render or one coat render – they all essentially mean the same thing. Coloured render is a type of render that can be tinted to create any shade; it comes ready-mixed in a bucket, ready to apply to a substrate. It’s applied in a very thin layer on top of a flexible basecoat to achieve a finish that will remain crack-free for years to come. Thin coat renders offer the amazing advantage of being incredibly flexible but also very sturdy, so crack resistance is massively increased.

There are many different types of coloured renders available on the market, the most common being Silicone and Acrylic Render. Often people think of K rend when it comes to Silicone Render, however there are many manufacturers of silicone render, all of varying qualities.

Silicone Render has taken the render industry by storm and is now really popular with property owners because of its self cleaning capabilities; it looks newer for longer, which is pretty important when it comes to making sure your coloured render looks nice in the long term. It’s also a really great option because it is highly breathable and vapour permeable – it’s therefore great for a range of substrates, including older buildings, due to the fact that it works towards preventing water ingress.

Acrylic Render on the other hand is also well-known when it comes to coloured render because it holds onto colour pigment really well, creating bright and vibrant render finishes that are resistant to UV. Acrylic Render lacks the breathability and self cleaning capabilities of the silicone, however it is impact resistant so is ideal for those who live with kids or in an area where your render is at high risk of being knocked.

Why is Coloured Render better than Coloured Paint?

Because coloured render can offer all of the aforementioned benefits, using coloured paint on its own pales in comparison. When using just coloured paint as a standalone finish, you’re more likely to see hairline cracks develop within the paint which can really damage its overall appearance – this is purely because it lacks the strength that a render possesses. Although coloured render is more expensive, we always recommend using it because it is a longer term solution. 

Nevertheless, coloured paint does have its place. Our Silicone Paint is ideal for refreshing the external appearance of an existing render. It can be tinted to create any shade, so is ideal if you have an existing EWI Pro render as we can easily match the colours up for you. It’s also hydrophobic, so will go the extra mile when it comes to reducing water ingress.

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premium bio silicone render

What is the Premium Bio Silicone Render?

New Render New Home

We are so excited to have added the Premium Bio Silicone Render to our product line-up we thought we’d write all about what it can do for you. If you’re facing ongoing issues with organic overgrowth or cracked render, read on to find out exactly what the Premium Bio Silicone Render can do for you.

The EWI Pro Premium Bio Silicone Render is newly released and is said to be the brands’ most high performance silicone-based render yet. So what sets this render apart from your typical silicone render?

Premium Bio Silicone Render – what can it do?

While Silicone render is already renowned for its amazing self-cleaning capabilities and numerous other advantages, the Premium Bio Silicone seems to take this characteristic to a whole new level.

The enhanced properties of the render means that this is the best render for maintaining colour and a clean appearance.


Premium Bio Silicone Render actively combats any signs of organic growth that occurs on the surface of the render, easily breaking down surface vegetation with its highly hydrophobic and overgrowth-repellent surface.


Where most silicone-based renders will have a level of protection against UV rays which can fade the more intense and vibrant colours, the Premium Bio Silicone offers enhanced protection. Brighter colours will stay vibrant for longer due to this extra level of resistance, meaning that the external appearance of the property is far better maintained. Check out our colour chart to view our full range of render colours. 

Mechanical Resistance

Mechanical resistance essentially means a renders ability to withstand any impacts without cracking. Premium Bio Silicone Render offers an increased level of mechanical resistance, so if your property is prone to these problems then this is the perfect render for you.


As with the standard classic Silicone Render, breathability is still an essential component of the Premium Bio Silicone Render. Heritage properties and high performance blockwork structures all require a breathable but protective coating to ensure that water vapour is able to escape from the building fabric.


As with all thin coat render technology, flexibility is an integral part of the Premium Bio Silicone Render. Once applied on top of a reinforced basecoat such as our EWI-225 Premium Adhesive, it will provide a long-lasting finish that will be able to adjust to structural movements without cracking.

The Premium Bio Silicone Render really covers all the base(coats) when it comes to tackling the common issues associated with render, and we can’t wait to see how it performs! Premium Bio is available in our standard range of colours and can be tinted to match any shade.

So there you have it! An overview of our new thin coat coloured render. Premium Bio Silicone Render is an exciting launch and we think it’ll be a real game-changer, so get your orders in early and be the first to try it out!

We upload new blog posts every Tuesday and Thursday, so stay tuned for more content.

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EWI-310 Universal Primer vs. Rendagrip

EWI Pro Universal Primer or Rendagrip? What’s the difference?

Rendagrip is a primer produced by the brand Everbuild, who manufacture render primers and other building materials; their extra grip bonding agent is very similar to the EWI Pro Universal Primer. Both are essentially used to create a mechanical key on smooth surfaces that are difficult to render.

Primers can be an area of confusion when it comes to choosing the right one for the right substrate. Lots of installers will have a selection of preferred primers; whether its from the EWI Pro range or another brand, priming can mean the difference between a successful installation or one that causes problems further down the line.

That’s why a common question asked by customers who are new to EWI Pro primers is the difference between our Universal Primer and similar products, like the Rendagrip primer.

Keep reading for more information about both products, or check our our complete guide to EWI Pro primers.

What is the Universal Primer?

The Universal Primer is specially designed to prepare the substrate before applying EWI Pro adhesives. It dries red in colour, so ensures that you can see where exactly it has already been applied, thereby minimising waste. The primer itself contains quartz aggregate suspended in a binding solution; the quartz aggregate adheres to the substrate and creates a textured surface, which is important to create a mechanical key for the adhesive to bind onto. Universal Primer also ensures that the absorptive capacity of the substrate is reduced.

What is Rendagrip?

Rendagrip is a strong grip render primer, containing quartz aggregate to provide a mechanical key before rendering. The Rendagrip is red in colour so you can see where you’ve painted it already, and the actual formula not only enhances adhesion but also limits the absorptive capacity of the substrate.

What’s the difference?

The differences between the two are not huge, and some installers may prefer one over the other in terms of differences in application. However, when using a full ‘system’ e.g. EWI Pro, we always recommend sticking with a primer produced by the same brand as the render. This is especially true for EWI Pro primers, as all elements of the system are formulated to work in conjunction with each other. Any clashes in material are eliminated during manufacture to ensure that the products work in harmony.

The advantage to this is that you don’t need to buy your materials from different places. We take a whole-system approach when it comes to render and EWI, and so we sell all the necessary materials through our online shop. This means that everything you need is delivered together at the same time. You receive one invoice for all of your materials and the struggle of navigating different shops and making separate payments for different products is completely eliminated.

Alternatively, our sales team can process the order for you and calculate exactly how much you will need of each product, so product waste is significantly reduced. Alternatively you can try out our quick and easy materials calculator for a guide on the amount of materials you will need; it’s very simple and at the end you get a free quotation! We’re all about ensuring convenience for installers!

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basecoat for rendering

The Best Basecoat for Rendering?

The Best Basecoat for Rendering

Our range of basecoats is growing more and more extensive, so we thought we’d write about our top of the line basecoat, the Premium Basecoat, which is undoubtedly the best basecoat for rendering. We’ve also released some new branded slogan t-shirts! The ‘All About that Basecoat’ t-shirt is one of our favourites, and we think our installers will love to wear these on-site! So have a read and check out the t-shirt pictures…

All About that Basecoat?

When it comes to finding the best basecoat for rendering, the Premium Basecoat ticks all the boxes. It’s incredibly strong, breathable and flexible to ensure a render system that lasts. We always recommend using the Premium Basecoat on painted or rendered substrates for strength and stability.

As a multi-purpose adhesive, the Premium Basecoat can be used in two ways: for securing insulation boards to a substrate, and as a basecoat for rendering using a thin coat render.

Why use the Premium Basecoat?

Our Mineral Wool insulation system requires the use of the EWI-225 Premium Basecoat. This is because Mineral Wool insulation boards are much heavier than your basic EPS, so they require an extra strong adhesive – much like using super glue rather than plain old PVA.

We’ve previously written all about the difference between all of the EWI Pro adhesives in our ‘Ultimate Guide’ blog post, however to give a brief overview: the Premium Basecoat differs from our Basecoat Adhesive due to the fact that it is made of Portland cement, which is much stronger than other cements therefore creating a stable basecoat for rendering. It also contains strands of fibreglass within the material, ensuring extra tensile strength and flexibility. This means that the adhesive remains strong and stable, but also has a level of flexibility to ensure the render on top stays free of cracks.

As part of the reinforcement basecoat layer, the Premium Basecoat works well in conjunction with a Fibreglass Mesh, which is embedded within the basecoat. Each strip of mesh is overlapped, so any expansion or contraction of the external walls during heating and cooling will not cause the basecoat to crack because of the Fibreglass Mesh.

Why Choose a Breathable Basecoat?

Choosing a breathable basecoat with a breathable render finish (such as our Silicone Silicate render and Silicone render) ensures one key advantage: water vapour can pass easily through both layers of material.

This means that cracking and blown render will be significantly reduced, as well as build-up of damp within the render system. Breathable materials are also essential for older properties to ensure that the building fabric remains structurally sound.

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common mistakes during EWI

Common Mistakes during EWI Installations

Common Mistakes during EWI Installations

Life doesn’t always go to plan – sometimes common mistakes during EWI installations are made and things can go wrong. It’s always frustrating when something goes wrong, but rest assured there is usually a solution to the common mistakes that are made during EWI installations! We have a close relationship with all of our installers who come to us for technical advice when things don’t go as planned, which is why we know exactly how to fix the usual issues!

Our render and EWI systems are all highly specialist and need to be installed properly for full functionality. With that said, we do offer training sessions and the chance to become one of our approved installers if you attend. These sessions run every Thursday from 10am onwards and teach attendees all about our systems, how to install them and what the products are all about.

For installers who are just starting out, it takes a while to get used to the installation process, including on-site organisation, timings, materials and how best to use them. So with the intention of pre-empting any problems, here are a few common mistakes and solutions that an installer might face during an EWI or render-only installation.

On-site Planning and Organisation:

A common mistake during EWI installations is a lack of organisation and planning. Installing EWI is a process that not only involves high skill but careful planning of timings. There are many things that require an installers attention, and slip-ups can easily cause a halt to on-site works, wasting your time and money! Here are a few things to do with planning and organisation that may go wrong…

Delivery doesn’t come on time

When ordering materials, careful planning needs to go into making sure you are ordering the right quantities and that you are ordering far enough in advance to ensure that the materials arrive in time for the job to start. It’s so frustrating when workers are idle on-site because the materials haven’t arrived yet; with some companies, delivery times can be slow and on-site delivery may not even be on offer. One of our key priorities at EWI Store is making sure that we offer next day delivery. We aim to get our materials out to installers as quickly as possible, and we even have our own delivery drivers to do the job to make sure it happens!

Furthermore, if you do find that your materials are late then feel free to pop down to our premises and pick up some starter tracks so that you can at least be doing something while you wait!

Weather Conditions

When it comes to EWI and render, careful attention must be paid to the weather conditions. The materials cannot be used at low temperatures (unless you’re using our Winter Adhesive and Mineral Render!) and they cannot be used when temperatures are too high. The installation process also cannot be carried out during rain, because as we know damp can inhibit the functionality of the insulation. Always be on top of things by keeping an eye on the Met Office weather updates, this way you hopefully won’t find yourself in a situation where all of your workers are on-site and unable to do anything due to rainy conditions!

Installer-Client Communication

Part of on-site organisation involves communicating with the client to ensure that your requirements in order to carry out the work are met. If you find that the client has gone off to work and left you without access to the property for water and electricity, then you may find yourself wasting money on bottled water and even a generator. Communication with the client is key to ensuring a smooth installation process!

Drying times

Different materials at each stage of the EWI installation process have different drying times. When materials aren’t left to dry for long enough, or they’re left too long and are no longer workable, you may find that the quality of your work is impeded upon. For example, a common mistake during EWI occurs when the basecoat is left too long in the bucket and then applied directly to the substrate without re-mixing it will set much quicker and its workability will be dramatically decreased, resulting in a not-so-smooth finish. Always pay attention to the drying times on the bag, and attend one of our training sessions where all of these things are covered!

EWI Materials and Common Mistakes:  

At EWI Store, we offer free training sessions for any installers who are keen to use our materials. Those that attend are then qualified as approved installers, which means they have the knowledge and know-how that is necessary for a successful installation. Unfortunately, sometimes things can go wrong with materials on-site, whether it’s user error or other. The following are some examples of these problems.

The render is applied too thick

Our thin coat renders are designed to be applied just a few millimetres thick. Most installers who have used EWI Pro thin coat renders before will know that the thickness of the application should match the grain size. So, if you’ve chosen a 2mm grain size then you should apply it at a thickness of 2mm.

For many installers it can take a while to get used to this, and often common mistakes during EWI occur when the render is applied far too thick, purely because installers are more used to working with plaster and cementitious products with thicker application rates. In order to fix this, the quickest method is to use a plastic render float to scrape the render back to the correct thickness. Make sure you keep an eye that all the workers are applying the render correctly, as if not you will need to act fairly quickly in order to scrape it back.

Plastic fixings break

Our plastic fixings are designed to be used with our EPS (expanded polystyrene) insulation boards. One of the common mistakes during EWI is to use Plastic Fixings for unsuitable insulation materials; for example, Plastic fixings will not be suitable if you are installing Mineral Wool or Wood Fibre insulation, as these materials are too heavy for the fixings to be able to hold their weight. Not only this, but all fixings need to go through both the insulation board and the substrate in order to be totally secure. If your fixings are breaking, then it could be that you aren’t drilling them in far enough. After a while you should be able to judge this by eye, but to be really sure you’re drilling far enough through then we recommend putting a piece of tape on the drill bit to indicate where you would stop drilling.

Basecoat and mesh can drag

When installing Fibreglass Mesh and embedding it within the basecoat layer, the mesh is first placed onto the basecoat and then, starting from the bottom, a trowel is used to drag the basecoat through the mesh, embedding it in the process.

With this technique the mesh can sometimes get caught, and rather than becoming embedded it is simply dragged back up the wall with the trowel creating a bit of a mess. To resolve this, we first  recommend making sure that the basecoat isn’t too wet before you attempt to embed the mesh. If this does happen, simply remove the mesh and start again, but if you find that there’s a tear in the mesh you will have to add another layer on top to reinforce this area.

There you have it! We hope that this was informative and helpful for those just starting out with EWI. Don’t forget to attend one of our training sessions which run every Thursday if you haven’t already. We upload new content every Tuesday and Thursday all about render and EWI, with information blog posts about different products, technical advice and answering customer’s FAQ’s.

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EWI Pro Adhesives: The Ultimate Guide

We’ve now gathered a pretty wide range of EWI Pro adhesives for our render and external wall insulation systems, but without any real clarification about which ones should be used with certain materials and in certain conditions.

Last time we talked about a specific range of our products, it was to provide an overview of our entire line of primers. This week we’re doing something similar and we are going to be talking about our range of adhesives and basecoats, so read on for more information!

EWI-210 EPS Adhesive

Our EPS Adhesive is designed for use purely for mounting EPS insulation boards onto a substrate. We only recommend using this adhesive for EPS because other insulation boards (Mineral Wool and Wood Fibre) are too heavy for it. It’s vapour permeable so will allow any trapped moisture to escape, all while maintaining a strong hold. This is a really versatile adhesive in that it can be used on almost any substrate, be it masonry, concrete, cement-lime or blockwork.

EWI-220 EPS Basecoat Adhesive

The EPS Basecoat Adhesive is designed to be used in two ways. As an adhesive, it is used to secure EPS insulation boards to the substrate (much like the EWI-210, but stronger). Secondly, it can be used as a basecoat for the mesh reinforcement layer. This is a really popular choice for installers because it has a dual purpose which limits the amount of products that are required on-site and also the amount of product that goes to waste.

EWI-221 Winter Adhesive

Much like the EPS Basecoat Adhesive, the Winter Adhesive is a dual-purpose product. It can be used as both basecoat and an adhesive, however the main difference here is that the Winter Adhesive can be used at temperatures down to zero degrees celsius (but no lower than zero) while still maintaining a strong adhesion. This is a fantastic solution to ensure that any hold-ups on-site due to winter weather issues are prevented.  

EWI-225 Premium Adhesive

This is our strongest and most flexible adhesive. It can be used as both an extra strong adhesive and an extra strong basecoat. We always recommend using this adhesive with Mineral Wool and Wood Fibre systems as this is a strong enough adhesive to be able to support the heavier insulation materials. The reason this is our premium adhesive is because it contains strands of fibreglass mesh within the material, which enhance its tensile strength and grip.

EWI-269 Lightweight Basecoat

Our Lightweight Basecoat is highly breathable and is perfect for heritage projects on substrates such as limestone and sandstone, and for use on high performance blockwork. This basecoat is not designed for use on top of insulation boards, but the good thing about it is that it can be applied at a thickness of up to 25mm in one pass without compromising its breathability. The Lightweight Basecoat also contains lime, which is why it’s so breathable and lightweight.

EWI-235 Dash Receiver

Last but not least is our Dash Receiver. In some ways the Dash Receiver is both adhesive and basecoat. It creates a smooth basecoat onto which the dash aggregates adhere to. The Dash Receiver is highly flexible and offers strong adhesion, so you can be sure it will remain crack free for years to come, while holding fast onto the dash aggregates.

EWI-104 Universal Tile Adhesive

The Universal Tile Adhesive is made a cement-based adhesive, with CT2E class adhesive capabilities. This is ideal for internal or external use and offers users a long correction time to enable the adjustment of tiles before it dries in order to achieve a perfect finish.

And there you have it! Our complete guide to EWI Pro adhesives. Any further questions, comment down below or get in touch with our technical team!

Recap: EWI Pro Adhesives

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coloured render ziegel

Applying Coloured Render to Ziegel Block

New Ziegel Block Building, New Coloured Render

When thinking about applying a decorative finish such as coloured render on Ziegel blockwork, it’s important that the materials you are using compliment the substrate (we’ve written previously about failed renders caused by this). Ziegel blocks are known for fire safety, thermal performance and excellent indoor air quality. With that said, the right materials are required in order to compliment the functionality of the substrate and subsequently reduce cracking.

At EWI Store, we have a range of solutions for applying coloured render to high performance blockwork successfully, so let’s take a look at the process and the materials required to ensure crack resistance and a lasting finish.

Why Build with Ziegel Blockwork?

In order to understand the kind of render that would be best suited for Ziegel, we need to take a look at what exactly Ziegel blocks are and what properties they have. Ziegel blocks are renowned for being high performance because they have excellent insulating capabilities.

Their high thermal performance is due to the air channels that run vertically through each block creating a honeycomb effect, while the clay itself has more air pockets made by sawdust that is burned off in the kiln during the firing process. Ziegel blocks are also a breathable building material as they can maintain the equilibrium of humidity by storing and releasing heat and moisture, helping to maintain room comfort and healthy indoor air quality all year round.

Ziegel are also a highly dense material, creating a uniform substrate that offers reduced thermal bridging with a quick and easy construction process. Although Ziegel is a high performance block, it does need finishing with a protective layer to prevent weathering. This is where coloured render systems are ideal, because the technology of the system means that the substrates functionality is in no way hindered by the coloured render, instead the materials that go into the render system compliment the substrate.

Applying the Basecoat to Ziegel Block

Ziegel block creates a uniform, continuous substrate which is incredibly easy to render in terms of creating a smooth surface; the only area that requires close attention is using the right materials and the right method of application. You can decide based on the climate and weather conditions whether or not you need to apply a two-coat system or a three-coat render system for this kind of blockwork. The default for the UK tends to be the three-coat system because the Lightweight Basecoat and render on its own will not withstand the weather conditions.

Two-coat system:

The two-coat system consists of the application of the Lightweight Basecoat, then a tightcoat and then a render.

In a typical render system on an ordinary substrate, a substrate primer would be necessary to limit the absorptive capacity of the substrate. However, when rendering a Ziegel substrate, to limit the absorptive capacity of the substrate you do not need to prime. Instead, you spray apply a first pass of the Lightweight basecoat at approximately two thirds of the thickness it should be applied at – around 12mm. You leave this to ‘pull back’ and dry slightly before appyling the final one third to take the basecoat up to its total thickness.

The Lightweight Basecoat needs to be left for a period 0f 24-48 hours to dry, then the tightcoat is applied. This consists of another thin layer of the Lightweight Basecoat; it is applied to the dried basecoat and is sponged or rubbed up to achieve the required texture. Once the tightcoat has been applied, it can be primed and painted or primed and rendered using a ready-mix render (e.g. Silicone or Silicone Silicate). You can also use Mineral Render (and then paint with Silicone Paint) or you can use Monocouche render. The main thing here is that the tightcoat must be primed if you are using a ready-mix render such as Silicone or Silicone Silicate, because otherwise blooming may occur across the lime basecoat.

Three-coat system:

A three-coat system is the standard system that is recommended for use in the UK. The three coat system involves applying the Lightweight Basecoat in two passes, as outlined above. Once the Lightweight Basecoat has cured (after 24-48 hours), a layer of the Premium Adhesive with Fibreglass Mesh embedded is then applied on top. The Premium Adhesive is then primed using a render primer, before the render of your choice is applied; whether it’s Silicone, Silicone Silicate, Mineral or Monocouche.

The reason that the Premium Adhesive is applied as an extra layer is because it is far stronger than the Lightweight Basecoat, and when applied with a Fibreglass Mesh embedded within the adhesive it provides the required tensile strength to be able to withstand harsh weather conditions without cracking.

Applying Silicone Coloured Render to Ziegel Block

When applying coloured render to a Ziegel substrate, we really recommend the use of Silicone Render as it’s incredibly flexible, breathable and hydrophobic. It will therefore resist any cracking, prevent water ingress and allow water vapour to escape from the building fabric. It’s currently our most high performance coloured render and is an extremely versatile and popular solution for a wide range of substrates.

Silicone Render can also be tinted to create any shade of colour (hence the name coloured render). If coloured render is of interest to you, you can view our full shade range using our render colour chart, or you can purchase a coloured render sample pot.

For any further questions about applying render to Ziegel block, contact our technical team or leave a comment down below – we are always happy to help!

We upload a new blog post every Tuesday and Thursday, so stay tuned for more content!

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Essential Tools for Rendering and EWI

The best render and EWI jobs are those that you are most prepared for. At EWI Store, our main goal is to make sure that every installer is fully equipped for their next EWI job with minimal fuss. When you go through EWI Store, you can find everything you need in one place, along with our technical expertise and installation advice which is always on hand. With that in mind, in no particular order, here are our essential tools that any installer should have on site with the relevant links so that you can pick up anything you need quickly and easily!

Essential trowels for rendering and EWI

Stainless Steel Trowel

If you’re a renderer, then you won’t be able to live (or do any work) without your trowel on-site. Our stainless steel trowels are reliable and hard wearing – fantastically multi-purpose in that they are ideal for use with our basecoats, adhesives, thin coat and thick coat renders. They help to apply the product super smooth and at the appropriate thickness.

Square Notched Trowel

The square notched trowel is a fundamental tool for any render or EWI installer. It’s primarily used to ensure that the basecoat is applied at the appropriate thickness and to smooth out the adhesive onto the back of the insulation boards.

Bucket Trowel

The bucket trowel is a pretty standard trowel, nevertheless it’s very handy for scooping, mixing and distributing – be it adhesive or render.

Plastic Render Float

If you’re using one of our thin coat renders, then this is a fundamental tool because you need to use it rub up the render after it’s been applied in order to get the textured finish. Using the plastic render float means that the individual grains within the render can be revealed.

Sponge Float

The sponge float is used on the basecoat layer to smooth out any trowel lines that were left during application. If you’re using a thin coat render, this is an essential step because any imperfections in the basecoat are sometimes visible through the render.

Corner Trowel

The corner trowel is primarily used to evenly distribute product around the corners and achieve a seamless finish. This is certainly a multi use tool as it is often necessary for the basecoat layer and the render top coat layer.


This one isn’t necessarily essential, but it is a timesaver. The Speedskim essentially allows you to rule off your basecoat, covering a wider area than an ordinary trowel it means that you can get a flat surface in less time and using less energy!

Essential tools for insulation

Mineral Wool Knife

For use with both mineral wool and wood fibre, this is a really handy knife to have on site because you can jab it straight into the insulation and start cutting. Great for if you need to cut the insulation to fit corners etc.

Spirit Level

Essential for making sure your starter track is straight, which in turn means your insulation is laid straight.

Steel EPS Rasp

Best practice for a good quality EPS installation is to use a steel EPS rasp to remove the oily layer that sits on the surface of the EPS, and create a key onto which the basecoat layer can bind.

EPS Wire Cutter

If you are installing EPS, a really handy tool to have on-site is the EPS hot wire cutter. Essentially, it melts the EPS so that you end up with super straight lines and you don’t get a rough jagged mess and polystyrene absolutely everywhere.

Industrial Hoover

When you are rasping back your EPS, you will inevitably find that it goes everywhere and blows about in the wind. Something really handy to have on site is an industrial hoover. This way, one worker can be rasping the EPS while another holds the hoover underneath ready to catch all the fall-out.

Other essential EWI and render tools to have on-site

Large Bucket

Essential for mixing adhesive and more. Also best practice for rendering (especially coloured render) is to decant all your render buckets into one large bucket so that you can mix them all together and ensure a uniform colour.

Drill and Two Batteries + Masonry Drill Bits

Pretty important if you are using mechanical screw fixings – plus, always have a backup battery! Handy bonus tip for drilling mechanical fixings is to use tape on the drill to mark how far in you need to drill the fixings.


You’ll need a decent hammer for your plastic/metal hammer fixings.

Measuring Tape

Speaks for itself really, you’ll need to measure up your insulation boards if you’re cutting them etc!

Spades, Brush, Dustpan

Other essentials. You may find yourself needing to dig up some plants in order to gain access/move them out the way of the system, especially if you’re insulating below the DPC.

Window Covers

One of the most important things is to be mindful that you are on someone else’s property. Therefore, it’s your responsibility as the worker to protect windows etc. from damage and from getting render dripped on them.

Ladders and Stepladders

Always necessary! Make sure you follow the ‘working from heights’ guidelines.

Tank of Water

If you’re working on a domestic property, sometimes access to water isn’t available. Having a tank of water for mixing materials can be a lifesaver, so think ahead and always check with the customer whether you can use their water supply.

Safety essentials to have on-site

Gloves, Hard Hat, Boots, Goggles, First Aid Kit

Always use protection. And by that we mean protective work gear so that you aren’t putting yourself at risk. That means wearing work boots to protect your feet from falling materials and tools, goggles for when you’re rasping the EPS, and a hard hat to wear while on scaffolding. And importantly, always always always have a first aid kit on site (and someone who knows how to use it!).

Mobile Phone

In this day and age, it’s rare to find yourself without a mobile phone. However, accidents do happen and being able to contact emergency services is crucial so make sure it’s fully charged and easily accessible in case of emergencies!

So there you have it! Your basic guide to the essential tools to have on site. Any further questions? Call our technical team who are always happy to help, or leave a comment down below.

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render grain size

The Ultimate Guide to Render Grain Sizes

The render grain size that you choose can have an effect on several factors; our EWI Pro thin coat renders come in a wide range of grain sizes, from 1mm to 3mm. The reason that our renders have grains of different sizes within them is so that you can achieve a textured effect based on your own preference – whether it’s only very slightly textured (1mm) or extra rough (3mm), we cater for all tastes! If you’re looking for a way to create a unique, aesthetically pleasing exterior facade for your property, then check out our blog post on render design features for some inspiration.

Many customers frequently ask us about how choosing a different grain size may affect installation and/or cost. Generally, we advise that the larger the grain size you go for, the more render you will need to buy because the coverage rates decrease with the larger grain sizes. For a comprehensive guide on how much a coloured render system costs, check out our blog ‘coloured render cost per m2’!

Grain size can also affect how easily the render can be applied. Based on our technical experience, we have listed our grain sizes with all the pros and cons associated, and hopefully this will elucidate the situation further!

1mm Render Grain Size

Our 1mm grain size is our smallest render grain size. It is therefore applied at a 1mm thickness which is the thinnest that our renders can be applied at (the thickness that you apply the render should match the render grain size). This also means that in terms of cost per square metre, the 1mm grain size will cost the least as, compared to the larger grain sizes, a bucket of 1mm will go the furthest.

In terms of aesthetic appearance, 1mm render grain size is the smoothest finish that we offer. Depending upon our personal preference, the 1mm will give you more of a painted look, which can look really nice on certain properties, or if you’re looking to mimic your previous render.

The only downside to the 1mm is that because it’s applied so thinly, any textural issues or trowel lines within the basecoat will show through the render. It can also be trickier to install because of this and because of the fact that it has to go on in such a thin layer. If you’re after 1mm, then make sure you hire a professional with a high standard of work to carry out the job for you.

1.5mm Render Grain Size

1.5mm is our most popular grain size and is the choice of most installers. This is because it’s easy to install, it goes far in terms of coverage so it’s very cost effective, and because it’s more textured due to its slightly larger grain size, it also hides imperfections in the basecoat. Homeowners like this grain size because it doesn’t have a painted finish but it’s not overly textured – you can only really see it when you look closely!

2mm Render Grain Size

Noticeably, the larger the grain size the more tricky the render is to apply as the larger grain sizes can cause dragging and can be more challenging to spread over the substrate. Also, larger grain size means higher expense. Again, this is because you have to apply it in a thicker layer and therefore you get less out of a bucket. The true benefit of a 2mm grain size is that it hides imperfections within the basecoat and the substrate. Depending upon personal preference and whether you like a more bumpy, textured render, the 2mm can be the perfect choice, providing the benefit of ensuring that your render surface looks even.

3mm Render Grain Size

Buying a 3mm grain size render means it will cost the most overall. Again, this is because the larger the grain size the less the bucket will cover. Choosing a 3mm render grain size may cost the most, but it will give you the most textured finish – not quite pebbledash but very noticeably textured even from a distance. Because it has such a textured finish, this means that it’s considered to be one of the hardest to install due to the fact that the size of the grains creates a dragging effect which can be harder to work with.


The grain size that customers go for is always varied and really just depends upon personal preference. Hopefully this blog post made the difference in the grain sizes a little more clear will help the decision making process! Worth mentioning is the fact that sometimes grain size may affect the way the render colour appears. Larger grain sizes can cause a shadowing effect which sometimes makes the render appear darker than it actually is. We recommend you order a coloured render tester pot to help with choosing colours!

Stay tuned for more content! We upload to our blog every Tuesday and Thursday; whether it’s answering frequently asked customer questions or giving all the details about each of our products – we aim to cover it all. Comment down below if you have any further questions or give us a call to speak to our technical advice team who are always happy to help.

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Stages of an EWI Installation

Lots of customers hear about our external wall insulation systems by witnessing their neighbours installations, but often the stages and process of the installation are not very clear. Here at EWI Store, we set out to make sure that our customers are fully informed about our systems, including how they are installed and why we install them in certain ways. So keep reading to learn about the EWI installation process!

Wall Preparation

Before any works can begin, the external walls will need to be prepared. The preparation required tends to vary depending upon the condition of the building. In most cases, a simple rub-down will do, although sometimes we may need to remove your existing wall coating. If you are installing EWI onto a smooth surface, then you will need to use our EWI-310 Universal Primer (read about it here in our primer guide) to allow for the adhesive to stick to the walls. If the wall isn’t completely straight, then the EWI-260 Levelling Mortar must be used to dub the wall. Fungicidal wash should be used to remove any organic growth.

Addition of Starter Tracks to the wall

The correct starter tracks should be applied to the walls above the DPC. The starter tracks not only allow for the easy installation of insulation to the walls but also protects the bottom surface of the insulation against weather, damp and other damage. Clip on profile should be attached to aluminium starter tracks to create a neat finish between the starter track and the insulation.

Applying insulation to the walls

At EWI Store our basecoat can be used as an adhesive. The basecoat should be applied to the insulation using our modified dot and dab method (three dots in the middle and all around the perimeter). A notched trowel should be used to evenly spread the basecoat on the back of the insulation board. The basecoat should be about 4-5cm thick. When placed on the wall, mechanical fixings should be used to add some additional security to the insulation (6 fixings per square metre of insulation). Allow 2-3 days for the basecoat to set before installing the mechanical fixings.

Addition of Beading and Verge Trims

Before the addition of the basecoat, all beading must be applied. Beading is used to reinforce weak or impact-prone areas within the system, helping to prevent damage and reinforce the structural integrity. Each beading has its own special function and area of application:

Corner beads: Corner beads have mesh and sink into the basecoat. Corner beads reinforce the external corners of the EWI or render-only system.

Movement Beads: used inside corners in thermal insulation systems to create a permanent and weather-proof sealant of vertical movement joints.

Bellcast Beads: designed to provide a clean, natural stop to the render just above the damp proof course. The bellcast bead also drives water away from the wall.

Render Movement Beads: Should be used where there is a large expanse of render area. The render movement bead is used vertically and is designed to prevent cracking within the render through thermal expansion and compression.

Basecoat and mesh layer

After 2-3 days, another layer of the basecoat should be applied with a notched trowel over the top of the insulation boards at a thickness of 5-6mm. Fibreglass mesh is then embedded into the basecoat in vertical strips using the flat edge of a notched trowel. Each vertical strip of fibreglass mesh should overlap its neighbouring vertical strip by approximately 10-15cm. We use fibreglass mesh because it increases the tensile strength of the system and goes an extra step further in preventing cracks and impact damage.  

Render Primer

Render primer tends to be an optional step, however for best practice and for increased durability and adhesion you should apply a render primer to the basecoat. The render primer that you use will depend upon the render itself; if you’re using our Silicone Silicate render, then the SiSi Render Primer is the most appropriate. For our Acrylic render, the Mineral & Acrylic Primer is the most ideal, and so on. This should be painted on and then left to dry for 12 hours – check out our blog all about our primer range for a complete guide.


Once your final basecoat layer is dry, your render of choice is then installed over the top. When we talk about thin coat renders, we are referring to our Silicone, Silicone Silicate, Acrylic or Mineral renders. All of which can be mixed into any shade using our specialist colour tinting equipment.

There you have it! This is a very basic installation guide which should be used purely as an overview of an EWI install for informative purposes. Every installation is different, so if you have any further questions about installing EWI on your property then call our technical team who are always happy to answer questions!

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What makes a good external wall insulation installer?

Because external wall insulation is a fairly new concept for many people, customers are often worried about choosing the right installers and achieving a high quality of workmanship, because EWI isn’t a one size fits all situation – it needs to be tailored to the property.

Generally, we advise that customers go through us to find installers. This is because all of the installers that we recommend are trained by us in how to use our products, correctly following our system specification. By choosing to use an EWI Pro approved installer, you can guarantee a high quality finish.

However, it’s always good to pay an interest and be conscious of how things should be done. So we’ve put together this brief guide on what you should expect from a good external wall insulation installer.

A good EWI installer will carry out a property assessment

Before beginning any installation, a professional external wall insulation installer will make a detailed assessment of various important factors that need to be considered before going ahead with the installation.

Generally, a good installer will make an assessment of:

  • The building conditions and elements, ensuring walls, floors, roofs, windows etc are free from damp and mould growth with problems solved prior to installation.
  • The original building materials to determine the appropriate EWI materials to be used (e.g. breathable and non breathable materials).
  • Location and climatic conditions, i.e. exposure to wind driven rain/pollution and subsequently the appropriate materials to be used.
  • Ventilation, with careful consideration of its efficiency and functionality post-installation.
  • Moisture content of substrate and subsequent appropriate choice of materials/resolution of excess moisture.
  • Condition of wall surface (installation of parge coat as necessary).

A good EWI installer will ensure a high quality of workmanship

A good EWI installer will ensure that the following is carried out and completed correctly to a high quality of standard:

  • Use of the correct primer on the substrate to limit its absorptivity and increase adhesion.
  • Fully embedded mesh.
  • Tightly fitted insulation boards, no gaps and proper following of bond pattern.
  • Proper installation of fixings – appropriate method of drilling and sinking.
  • Air vents and drains left clear.
  • Sills and verge trim appropriately sealed.
  • Starter track is installed straight and level.
  • Window sills are level.
  • Application of materials to clean, dry surfaces.
  • Insulation continuity between walls and loft
  • Insulated window sills.
  • Specification of brick slips or highly durable finishes for areas with high traffic.
  • Correct installation of render finish and specification of appropriate system depending upon the climate conditions and property type.
  • Correct insulation around eaves and porch roofs.
  • Fittings and fixtures should be designed to be deconstructed so as to prevent collateral damage when replacing or removing.
  • Correct use of required beading.
  • Awareness of the effect of different materials on cold bridging i.e. metal.
  • Use of EPS caps on metal mechanical fixings.

A good EWI installer will ensure proper usage of materials

During our installer training (sessions run every thursday) we introduce our products, the different EWI systems we have on offer and how to correctly and safely install them. As a result, an approved installer will be able to ensure optimal performance of our products. The following are a few ideas for how an installer should correctly use our materials:

  • Renders, insulation, and adhesives should be stored appropriately away from detrimental weather conditions such as high heat, cold temperatures and rain.
  • Insulation boards must be dry before application. Insulation boards should not be installed when wet from rain water.
  • Insulation must be in its proper condition (i.e. undamaged) upon installation. Damaged insulation can cause pockets of moisture.
  • Installer should follow manufacturers guidance for best practice. All approved installers have been trained in the correct use of our materials, and customers are at all times at the benefit of our technical expertise and advice when needed.

For any further questions, feel free to leave a comment down below or give us a call. We upload a new blog every Tuesday and Thursday, so stay tuned for more content about technical advice and product information!

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indoor air quality

indoor air quality and external wall insulation

External wall insulation helps to improve indoor air quality and contributes to healthy living. This is because EWI will prevent the progression of damp and mould within the home, and will keep the house in good structural condition, tightly sealed against external pollutants while at the same time allowing for the circulation of fresh air.

Outdoor air pollution is a well recognised issue in large cities and towns where traffic, congestion and closely built houses contribute towards an environment that is harmful to human health. We all know about how this kind of pollution affects our environment and the ozone layer; however, the subject of indoor air pollution is little discussed, and as a consequence it is often overlooked.

The average person will spend 87% of their working days indoors. When you think about the quantity of time that is, be it at work or at home, the amount of indoor air pollutants that you are subsequently exposed to is enormous. The problem is that damp, pet dander, mould spores and more can become trapped within your home and can lead to eventual health problems.

How will EWI Improve my Indoor Air Quality?

As we know, external wall insulation is effectively an airtight barrier that surrounds the property, preventing heat loss in the winter and heat gain in the summer. While EWI will keep water and moisture out of your home, it will also substantially keep out external pollutants.

We’ve said it before and we’ll say it again, a good EWI installer will establish a good ventilation strategy so that fresh air can circulate within the house and stale or humid air can escape. Installing EWI on your property will certainly bring closer attention to your current methods of ventilation, and your installer will ensure that your property has several means of adequate ventilation. Most important in any ventilation strategy is that humid air has an easy escape route. This is extremely important for human health, and certainly goes towards the prevention of damp.

If you have any experience with damp in your home, you will know that it can build up on the walls, floors and more, creating a musty smell and often causing allergies and asthma. Damp poses an invisible threat in the form of dangerous spores that occupants repeatedly inhale, and in some extreme cases these spores can be toxic.  

Here at EWI Store, we aim to use breathable materials at every stage of an installation. This means that our systems will allow water vapour to pass through them, ensuring that the house can breathe and preventing any build up of damp behind the system.

Wood Fibre Insulation and Indoor Air Quality

Natural materials such as Mineral Wool and Wood Fibre are known for their low VOC (volatile organic compound) emission ratings. VOC emissions can cause ‘sick building syndrome,’ which is known for giving inhabitants headaches and allergies. They are emitted from many building products and can be responsible for numerous health issues.

One of the most common VOCs is formaldehyde, which has been found to be responsible for several indoor air quality and pollution-related health issues. Because of the fact that our Wood Fibre insulation is such a natural resource, its VOC levels are renowned for being extremely low. This means that with Wood Fibre insulation, the threat of VOCs passing into the building is minimal, and as a result your indoor air quality remains uncompromised.

Give us a call and talk to one of our technical specialists about indoor air quality and EWI if this is something you are interested in for your property! We upload new content every Tuesday and Thursday here on the blog, so stay tuned for more EWI-related blog posts; answering frequently asked questions and giving you all the info about our products and systems.

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re-rendering pebbledash without removing pebbledash

Re-rendering Pebbledash without removing Pebbledash

How do I get rid of pebbledash?

Re-rendering pebbledash without removing pebbledash can be difficult if the right materials aren’t accessible. Removing pebbledash is a painful process, because removing the render requires hard work with a hammer and chisel, with the added risk of damaging the original brickwork. Typically, pebbledash is made from a sand and cement render – an incredibly unforgiving material that was often applied as a means of covering up a bad build job or cheap brickwork.

With the growing popularity of coloured render, pebbledash has been taking a bit of a hit of late, with pebbledashed house prices falling to reflect a national dislike. However, as long as the pebbledash is in good condition, there’s no reason this can’t be rectified without the costly expense of removing it.

Ways to re-render pebbledash without removing pebbledash

So how do you re-render pebbledash without removing the pebbledash render? There are a couple of ways you can do this which we are going to explore…

  1. Smoothing over the pebbledash with the Lightweight Basecoat

One of the best ways of re-rendering pebbledash without removing pebbledash render is by smoothing over it with our Lightweight Basecoat. This is the ideal material to use, because it can be applied at a thickness of 20mm thick without compromising structural integrity. You wouldn’t want to put a non-breathable material on top of the pebbledash because water needs to be able to escape from the walls, otherwise you may find yourself in an unpleasant, waterlogged situation.

The first step in re-rendering your pebbledash is to ensure that any loose stones are rubbed off.

The next step is to prime the pebbledash using the 310 Universal Primer, this will limit the absorptive capacity of the pebbledash render and will ensure that any dust is settled; it also provides a good grip for the basecoat to adhere to.

Once the primer has been left to set for 12 hours, you can go ahead and start preparing the Lightweight Basecoat for application. One 25kg bag needs mixing with 5 litres of clean water, using an electric paddle mix. Once mixed, leave for 2-3 minutes before re-mixing and then apply to the substrate using a plastering trowel. We recommend embedding Fibreglass Mesh within the basecoat, overlapping each strip by 10cm to ensure crack resistance and tensile strength.

Once the initial coat of 5-20mm has set, apply a ‘tight coat’ using a plastic, metal or felted float. After this has set, we advise applying a thin coat render such as Silicone Render; this is highly breathable and is available in a wide range of colours, so will provide an aesthetically pleasing finish.

  1. Externally insulating on top of the pebbledash

Another method of re-rendering pebbledash without removing pebbledash render is by applying insulation boards to the existing pebbledash. Even 20mm of EPS insulation secured to the exterior of the property can increase its thermal efficiency and create a smooth surface for a fresh layer of render to be applied to. The method of preparation is the same; any loose pebbles should be removed and the wall should be primed with the Universal Primer.

The insulation boards should then be secured to the substrate using the 225 Premium Adhesive. This should be applied to the whole of the back of the insulation boards – we don’t recommend doing the dot and dab method for applying insulation to pebbledash. Mechanical fixings should also be used to secure the insulation boards to the pebbledash.

Once the boards are set in place, you should have essentially created a new substrate for re-rendering pebbledash without removing pebbledash. Best practice is to rasp to EPS to achieve a smooth surface and remove the oily top layer, and then you can apply your render basecoat. We recommend using the Premium Adhesive as a basecoat for extra strength, embedding fibreglass mesh within the Premium Adhesive to ensure a strong and stable surface for the render. Finally, you can prime the basecoat using the SiSi Render Primer, leaving it to dry for 12 hours before applying either the Silicone or Silicone Silicate render.

And there you have it! Two easy ways to re-render pebbledash without removing the pebbledash render.

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advantages of wood fibre insulation

The Advantages of Wood Fibre Insulation

The Advantages of Wood Fibre Insulation : it’s all in the trees…

Wood Fibre insulation is a fairly recent addition to the EWI Pro insulation catalogue, so we’re going to talk about the advantages of Wood Fibre insulation. Today’s blog is going to be looking at a few of the many reasons why you would want to insulate your home using the most natural of all insulation materials: Wood Fibre. 

Looking for a more general idea of how external wall insulation can benefit you and your home? Check out our dedicated blog here.

Wood Fibre is Eco Friendly

One of the main advantages of Wood Fibre insulation is how environmentally friendly it is. We source our Wood Fibre insulation from a company called Pavatex, who aim to ensure that their Wood Fibre production process is as eco-friendly as possible. Pavatex are sustainable and environmentally conscious at every turn, creating their Diffutherm insulation boards from waste shavings created by local sawmills that use wood from sustainable forests. Indeed, Pavatex claim not to use ‘any old wood’ for their eco friendly insulation, a statement that is further emphasised by their prestigious NaturePlus certification.

Wood Fibre offsets an impressive 1.6 tonnes of carbon for every ton of material. From the environmentally conscious timber sourcing and manufacturing process, to the actual purpose of the product (reducing energy consumption in homes), Pavatex have done everything in their power to make their Wood Fibre the most eco-friendly it can possibly be. It’s also 100% recyclable and compostable, so at the end of its long lifespan the Wood Fibre can be safely disposed of in a non-harmful way.

Wood Fibre is Breathable

Wood Fibre insulation is naturally vapour permeable. This means that water vapour can travel through the material from the inside to escape on the outside, an essential asset for most buildings in order to prevent damp and structural decay. This is an essential advantage of using Wood Fibre insulation when it comes to older homes. Popularly used with a highly breathable silicone render, or even a traditional lime render, Wood Fibre insulation systems offer a high performance solution for even the oldest of the UK housing stock.

Wood Fibre has a low thermal conductivity

Going back to basic science, wood is a poor thermal conductor and therefore has excellent insulating capabilities. In terms of U-values, a 200mm thick board of Wood Fibre attached to a 215mm thick solid brick wall can bring the U-value of the wall down to new-build standards – 0.18w/m2k.

Wood Fibre is Fire Safe

Fire safety for cladding materials is understandably a large concern for many homeowners since the Grenfell tragedy, however Wood Fibre insulation is rated a Class E combustible material. This is because rather than encouraging the flames to grow, the timber typically chars which in turn slows down the spread of fire.

Wood Fibre insulation offers a tight thermal envelope and improved indoor air quality

Another of the many advantages of Wood Fibre insulation is that because external wall insulation is secured to the exterior of a property, the thermal envelope is much more complete than with internal insulation as there are practically no gaps in the insulation. This leaves no room (literally) for thermal bridges, which means that the overall effectiveness of the insulation is much higher. What makes Wood Fibre unique is that it’s incredibly easy to install because it is tongue and grooved, meaning the boards slot together seamlessly so gaps between boards are minimised.

As well as this, because Wood Fibre insulation is such a clean material, it does not release any kind of harmful chemicals and its insulating capabilities prevents harmful emissions from entering the property through the building fabric. Indoor air quality is therefore much higher with Wood Fibre insulation.

Wood Fibre Provides Sun Protection on Lightweight Buildings

Another of the advantages of Wood Fibre insulation goes hand in hand with its abilities to prevent heat loss. Wood Fibre insulation keeps buildings significantly cooler during hot summer days where solar gain is at a maximum. This is because it has the highest thermal mass properties of all insulation materials; this means that Wood Fibre can absorb and retain heat, slowing down the rate at which it enters the interior space. This is ideal for lightweight building structures, such as timber and steel frame, where protection against solar gain is at a minimum.

Not only does this reduce energy bills by minimising the need for air conditioning during the summer months, it dramatically improves the thermal comfort of the building, improving lifestyle and wellbeing.

So there you have it! Wood Fibre is a remarkable insulation material that can offer a building many of its numerous advantages. We’ve previously written a blog all about our Wood Fibre insulation so for more information check that out, or if you’re looking to compare Wood Fibre with our other insulation materials then have a read of our blog post ‘the best type of insulation for EWI?’.

We upload new content every Tuesday and Thursday, so stay tuned for new blog posts all about EWI and render.

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dash receiver

Pebbledashing: Dash Receiver or Cement Mix?

Our Dash Receiver is a one coat solution to all of your pebbledash requirements. Pebbledash is a type of render top coat that is very roughly textured by pebbles and/or stone fragments; it’s a very common building method in the UK, dating back to the late 20th century. With pebbledash, you can still see the colour of the cement underneath the pebbles, so it often appears to be a dirty caramel colour when you look at it from a distance.

We’ve previously written a blog about what to do when you want to get rid of your pebbledash (check it out here) as admittedly it’s not all that popular in the UK these days. However, many people find that either they have no other choice but to replicate and replace it, or they actually like the way that a high quality pebbledash finish can look. For both of these cases, the EWI-235 Dash Receiver can produce great results. Looking for technical information? Have a read of the Dash Receiver Data Sheet.

Why is the EWI-235 Dash Receiver better than using ordinary cement?

The reason we would always recommend using the Dash Receiver over other cement-mix products is because it was designed and engineered to be used for the specific purpose of pebbledashing. Due to this, the Dash Receiver presents a strong and high performing solution to ensuring a pebbledash finish that will last.

Strength and High Adhesion

For example, because the Dash Receiver is meant to be used specifically to adhere to dash aggregates, it has been designed with strength and high adhesive capabilities in mind. This essentially means that rather than just sitting on the wall as a rock-solid, immovable mass, the Dash Receiver will maintain its hold on the pebbles and therefore reduce chances of the dash aggregates falling off the surface and creating an unfortunately irreparable and ugly appearance.


Using bog-standard cement to create a pebbledash effect means that it is not best suited for being exposed to the elements and is therefore lacking in weatherproofing capabilities. The Dash Receiver is waterproof and frost proof – it’s meant to be slightly exposed to the elements and can withstand this, whereas normal cement mix doesn’t cope well with exposure to weathering, hence the often dilapidated appearance of older pebbledash looks.

A Range of Colours

Unlike cement-mix products, our Dash Receiver comes in a choice of colours. Because the Dash Receiver still somewhat shows underneath the pebbles, colour can make a pretty big impact on the overall appearance of the pebbledash. As a result, we offer our Dash Receiver in white, magnolia, champagne and cream, so you can also choose which kind of dash aggregates to use in order to contrast nicely against the Dash Receiver as a background.

Durable and Flexible

When a building heats up and cools down, the external walls expand and contract minimally. This is often the cause of cracks appearing within render facades, and cement-based products are especially susceptible to this because they lack the flexibility to be able to move with the building and compensate for these minute changes in structure. The Dash Receiver has been designed to be highly flexible to ensure that your pebbledash finish will resist those unsightly cracks.

The Perfect Consistency

Our Dash Receiver is the perfect consistency for pebbledashing. It isn’t too viscous or too dilute, so the dash aggregates won’t drop off the surface or sink too far within the Dash Receiver. This not only helps to secure a long lasting adhesion but also helps to create a finish that looks as aesthetically pleasing as possible.

How do you install the Dash Receiver?



Stay connected for new content – we upload new blog posts every Tuesday and Thursday all about our products, with technical advice and answering customer’s FAQ’s.

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Six Amazing Render Design Features You Need

How to make your property stand out from the crowd

When looking to re-render your property, why not go for something a little bit more exciting than just a clean white/cream canvas? While a simple look is certainly timeless, being adventurous with different design features can create an incredible finish that will stand out from the crowd.

Coloured render is exciting enough and fairly new to the market, but what if you don’t want just a simple render on your property? There are so many beautiful properties throughout the UK with fantastic design features that are easy to recreate with the right materials and a bit of creativity, so keep reading for five design inspiration ideas!

  1. Brick Slips

At EWI Store, we often talk about how you can recreate the original look of a property by using brick slips, but we’re not just talking about an all-over brick effect. With brick slips, you have the ability to be truly creative in the render design features that you produce.

Red Brick Slips can look fantastic when used in contrast with a coloured render; for example, when installed under or above windows, around doors or as a feature right the way round the lower half of a property. Brick Slip Corners can be used to create an alternating pattern on all four (or more) corners of the property, establishing a fantastic design all the while reinforcing your property’s vulnerable corners.

It’s not just red Brick Slips that have the ability to completely transform a property, however. Why not try black or white, and contrast this with your choice in coloured render. White render with black Brick Slips as a feature can truly stand out from the crowd, and white Brick Slips with a dove grey render will give a soft but modern effect.

  1.  Wood Effect Render

Wood Effect Render offers the fantastic opportunity of creating mock tudor beams (check out our tutorial on how to create Wood Effect Render!). The tudor-esque look is a traditional and attractive look, however in reality older buildings are much less energy efficient. So, by recreating a tudor look on your modern property, you can achieve an eye-catching and pleasing design all while maintaining energy efficiency.

Combine Wood Effect Render with Brick Slips and you can achieve a unique and attractive render design feature with contrasting textures.

  1. Bands

Bands are as the name suggests: thicker bands of render, usually in a contrasting colour to the main render, that are strategically placed on the exterior of a property to enhance certain features. These are typically placed above windows, doors, across elevations and to make a feature of gable roofs. Bands are simple but incredibly versatile due to the range of colour options that are available – for example, a blue property with white bands around the doors and windows would present a sophisticated facade.

  1. Ashlar Cut Render

Ashlar Cut Render is a render design feature whereby grooves are cut into the render to create various patterns and shapes, whether it’s emulating a stone shape, creating simple horizontal lines or building features around windows and doors. This process is usually carried out on Monocouche Scratch Render and can be done using a range of tools to create different effects. The key benefit of Ashlar Cut Render is that it is so versatile and can be applied to any area of the property, whether it’s as a design feature on a porch area, above windows or isolated to one storey of the property.

  1. Quoins

Quoins are made from cut render at the corners of a building. Typically found in an alternating pattern, Quoins enhance the overall facade of a property, reinforcing the edges for a render design feature that appears affluent, strong and stable.

  1. Mosaic Render

We often talk about how Mosaic Render is perfect for below the DPC because it’s so durable and splash resistant, however it’s also great as a decorative feature on other parts of a property. Mosaic render would look amazing around pillars, on window frames, garden walls, near swimming pools and as a feature for a porch area. It’s incredibly long lasting and offers a unique render design that can look fantastic as a feature to the property.


Stay tuned for more content! We upload blog posts every Tuesday and Thursday all about our renders and external wall insulation systems, including technical advice and answering customer’s FAQ’s.

coloured render thermalite

Applying Coloured Render to Thermalite Blocks

Coloured render is a popular choice for many homeowners, but on a Thermalite substrate finding the ideal materials to create the coloured render effect can be tricky. Renowned for being one of the most popular high performance building blocks, Thermalite offer excellent thermal performance, breathability and moisture resistance. The only thing about Thermalite blocks is that they create an extremely soft substrate and therefore can be tricky to render. Ideally, Thermalite blocks need finishing with a material that matches them in softness and flexibility in order to prevent cracking.

We have seen so many cases where an inappropriate render has been applied to a high performance block substrate, and we know that many builders experience problems when faced with high performance blockwork, as knowing the right quantities of materials can be extremely tricky and a bit of a balancing act. Luckily, here at EWI Store we have come up with the perfect solution for how to apply coloured render onto Thermalite blocks.

All About that Basecoat: Coloured Render on Thermalite Blocks

Our Lightweight Basecoat is ideal for use with Thermalite blocks because (as the name suggests) it’s incredibly lightweight and therefore works well in conjunction with the Thermalite, providing a stable base for the coloured render. Because the Lightweight Basecoat contains lime and perlite, it has the breathability and flexibility of the lime while also maintaining the strength of the perlite; it’s therefore ideal for a soft and lightweight substrate such as Thermalite, because the Lightweight Basecoat will resist the common issue of cracking and render failure.

When using the Lightweight Basecoat with Thermalite blocks, you can apply a two-coat or three-coat system.

Two-coat system:

The two-coat system consists of the Lightweight Basecoat, which is applied in two passes. Rather than priming the substrate, two thirds of the total basecoat thickness is spray applied first (approx 12mm thick), then left to ‘pull back’ and dry slightly. After this, the final one third is applied to take the basecoat up to its total thickness. Once this has set for 24-48 hours, a tightcoat is applied; this is essentially another thin layer of the Lightweight Basecoat which is sponge or rubbed up to achieve the required texture. This is then left to set before it is primed using a render primer and then the coloured render of your choice is applied (Silicone, Silicone Silicate, Mineral or Monocouche).

Three-coat system:

Most recommended for the UK is the three-coat system. This is because of the weather conditions that we experience here – the two coat system most likely would not be able to withstand the harsher conditions.

The application of the Lightweight basecoat is the same for the three-coat system as it is for the two; the basecoat is applied in two passes. The key difference is that after the basecoat has been left to set, the Premium Adhesive is applied and Fibreglass mesh is embedded within it. This will give the system the strength and crack resistance that is required to be able to hold up against the harsher climate. After the Premium Adhesive, a render primer and then the coloured render of your choice is applied.

The Best Coloured Render for Thermalite Blocks?

When choosing a coloured render, there is a vast array of different brands and different renders that all offer a variety of benefits. Silicone Render is a well known coloured render, offering breathability and vapour permeability. Silicone Render is a thin coat coloured render and, as the name suggests, is applied in an extremely thin layer which means it is highly flexible (see below for a video demonstrating just how flexible it really is!).

Flexibility is an important quality to look for when choosing a render for Thermalite blocks, as the blocks are so soft that they very easily expand and contract during heating and cooling. A hard and unforgiving render such as sand and cement would only crack with the movements of the blocks. Check out our blog post ‘Sand and Cement Render on High Performance Blocks’ for more information!

We recommend using Silicone for rendering Thermalite blocks, as it will compliment the substrate with its vapour permeability and will also prevent water from getting behind the system and into the blockwork. It’s important for Thermalite blocks not to get wet, because during the process of drying they can very easily crack due to their softness; Silicone Render creates an impregnable shield against water ingress.

And there you have it – how to apply coloured render to Thermalite blocks. The process is very simple and the materials really save going through the experience of a failed render. For any further questions about using coloured render on Thermalite blocks, call up our technical team or leave a comment below! We’re always happy to give our free expert advice.

Applying render to a range of substrates…

Recap of Materials for Applying Coloured Render to Thermalite


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Applying Coloured Render onto ICF

What is ICF?

ICF (Insulating Concrete Form) are hollow foam blocks that are stacked into shape, reinforced with rebar steel and then filled with concrete. The ICF blocks combine the thermal capabilities of EPS insulation with the strength of concrete and rebar steel, creating airtight, energy efficient and outstandingly structurally stable walls.

Here at EWI Store, we use EPS insulation in our external wall insulation systems as a means of retrofitting thermal insulation to a property in order to upgrade its thermal performance. With ICF blocks the insulation is already part of the substrate, however, the exterior polystyrene is not weatherproof and therefore needs finishing with a coloured render system. In this blog, we’re going to talk about how you can apply coloured render onto ICF.

How to apply Coloured Render onto ICF substrates

The method of application of coloured render onto an ICF substrate is very similar to applying coloured render to EPS insulation boards. First the basecoat must be applied to the substrate using a trowel to create a smooth surface before the thin coat render can be applied. To create the basecoat, you can use either the EWI-220 EPS Basecoat Adhesive, or the EWI-225 Premium Adhesive for an extra strong and stable base.

Fibreglass mesh needs to be embedded within the basecoat layer in order to enhance tensile strength and crack-resistance. Once this is done, the basecoat needs to be as smooth as possible because any major imperfections will be visible due to the fact that the render itself is applied in such a thin layer.

The basecoat layer needs to set for a period of 24-48 hours before any more work can be done. After it’s set, a render can be applied; this will depend upon the type of coloured render that you intend to use. For example, our SiSi Render Primer is designed for use with our Silicone Silicate Renders. The primer needs to be left to set for 12 hours, and then finally the coloured render can be applied!

Contact our sales team for a copy of our full installation guide!

Why use Coloured Render on ICF

Coloured render can offer your property a world of benefits and is an excellent finish for ICF substrates. Coloured renders are flexible and crack-resistant because they are applied in such a thin layer (it can vary from 1mm-3mm thick depending upon the grain size you go for!). When choosing a coloured render, you can select from our expansive colour chart or we can custom mix the render into any shade, we also have a blog post ‘coloured render cost per m2’ which outlines really clearly how much the system typically costs. 

With EWI Store, we offer a wide selection of renders for a range of substrates:

Silicone/Silicone Silicate Render: Silicone-based renders are a high performance option when it comes to coloured render. Not only does Silicone Render possess self-cleaning capabilities (although silicone silicate less so), both are also highly breathable and hydrophobic, thereby preventing water vapour from becoming trapped within the substrate and the render system.

Acrylic Render: Acrylic is what most people think of when they think of thin coat coloured render. It is most renowned for coloured render because it is so great at holding onto colour pigment (think of the vibrancy of acrylic paint). Acrylic render is very impact resistant, so if you have kids who love kicking footballs against your walls acrylic render is right for you!

Mineral Render: Mineral render is a great choice if you live in a particularly harsh climate. Because of the fact that it’s fast drying, it can be installed in cold or humid conditions, nevertheless it does require painting with a silicone paint after it has dried to prevent the formation of lime bloom – which is essentially like a cement ‘disease’ which makes your house render appear patchy.

So there you have it. Our full range of renders and how they are applied to an ICF substrate. For any further questions, comment down below or call up our technical team who are always happy and on-hand to help.

Applying Render to a Range of Substrates:

Recap of Materials required for applying coloured render onto ICF:

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10 Tips for Avoiding Condensation

10 ways to avoid condensation in the home!

Part of your external wall insulation aftercare and maintenance includes taking actions to reduce excessive condensation within the home – we thought we’d cover that today.

We often talk about how water and condensation are detrimental to external wall insulation systems, and how breathable materials can really help reduce the risks of these issues – you can read this blog for more information about it. However, while EWI is a great preventative measure against moisture entering your home, you do need to take steps to ensure that your home is well ventilated and condensation-free internally. Avoiding condensation can be easier than you think!

1. Ventilation strategy

With a good external wall insulation install, comes a good ventilation strategy. Any decent installer should be able to recognise where you will need ventilation and where your walls have too high a moisture content for you to safely install EWI. Vents are designed to ensure that your home is ventilated in a controlled way. For example roof vents, trickle vents and foundation vents can work wonders at reducing condensation build up.

2. Warmer walls (insulation)

External wall insulation itself should help to prevent condensation by retaining the heat in your walls and thus slowing down heat transfer. This basically means that when warm, humid air from indoors hits your walls, it’s not going to turn into condensation because the temperature difference will be significantly reduced. The key with insulation is that thermal bridges need to be minimised as much as possible, because where there are gaps in the insulation condensation can gather and cause problems.

3. Open windows for a short while after you’ve had a shower or cooked food.

Excessive condensation and humidity is created after hot water has been used in the home. Ever noticed how steamy your bathroom gets after you’ve had a nice long shower, or how your kitchen windows mist up when you’re cooking lots of different foods on different hobs at the same time?

Even opening a window a crack for five minutes or so can provide enough of an escape route for the steam. When airing a room like this it’s best to keep the door closed with the window open to prevent too much heat loss from other parts of the house, and also to stop the humid air moving into colder rooms and then turning to condensation there.

4. Extractor fans

Another key part of ventilation. These are great in bathrooms (especially if you don’t have a window) and kitchens as a means of extracting water vapour from the air and reduce the necessity of opening windows and potentially losing heat from inside.

5. Dehumidifier

If your home is particularly prone to damp and mould, then a dehumidifier could be the best option as a preventative measure to avoid condensation. It’s always better to be safe than sorry – moisture is particularly detrimental to EWI. Another thing you also might want to consider is that damp can often occur on the back walls of built-in wardrobes, so a hanging wardrobe dehumidifier could be really effective.

6. Double glazing

When you install EWI, it’s always best to install any new windows before the installation. With that in mind, it does not make any sense whatsoever to replace inefficient single-glazed windows with more of the same. Single glazed windows won’t retain any sort of heat, so temperature-wise the actual glass is going to be cold and therefore when the warm air from inside hits the cold glass – boom! Condensation. Double glazing can fix this issue because there is a pocket of air between the two panes of glass which slows down heat transfer and therefore avoids condensation.

7. Have a Good DPC

As we mentioned, any professional EWI installer will be able to check for rising damp and also check that your DPC (damp proof course) is in good working order before installation. Some people don’t even have DPC’s, and in this instance you may want to consider a chemical DPC to avoid rising damp, such as Dryzone Damp-Proofing Cream.

8. Avoid drying clothes indoors

Wet clothes in a warm room equals evaporation and condensation. Enough said. But really, if you need to dry your clothes indoors try to use an airing cupboard or turn one of the rooms in your house into a temporary laundry drying room. Simply switch the heating off in that room (your EWI should keep the room at a comfortable temperature without the heating on anyway), open a window slightly and keep the door closed. It will be worth it in the long run when you avoid condensation and reduce your chances of damp.

9. Leave a gap between your furniture and the walls

Mould often starts growing in warm, dark places such as behind large pieces of furniture. To prevent this and to allow for air circulation behind your furniture, you should leave an inch or so of space between the wall and the furniture. This should allow the walls to breath and prevent damp.

10. Keep your home at a constant temperature

With external wall insulation, the rate of heat loss from within your home is slowed down significantly. However, this is not to say that you shouldn’t have a regular heating pattern so that your home runs at a comfortable temperature and internal condensation is reduced. You can use your thermostat to do this, setting it to a specified temperature or by arranging for the heating to come on using a timer.

These are our top tips for avoiding condensation in your home! We hope this was helpful, if you have any questions then do leave a comment below or give us a call – we are always happy to help!

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The Best Weather Conditions for Rendering?

The Ideal Weather Conditions for Rendering?

Things don’t always go to plan when working on a construction site, and sometimes poor weather conditions can affect whether or not you’re able to start rendering. The current heatwave in the UK has meant that we’ve received many enquiries from renderers and homeowners about whether these are the best conditions for rendering, and we endeavour to give as much advice as possible to avoid situations where the render fails.

The ideal temperatures for installing render varies between manufacturers, however for EWI Pro renders it is advised that the optimal temperature for applying the renders should be between +5 and +25 degrees celsius.

This isn’t to say that this unprecedented heat wave should put a halt to all works, as we know that the daily temperatures have been well over 25. Renderers simply need to be able to find ways to work around the heat, and the same goes for when the weather’s cold. So here’s our advice on what to do when the weather conditions aren’t ideal for rendering!

Rendering in Hot Weather

We always advise not to use our materials in temperatures over 30 degrees. Most especially, we advise that if it’s a warm day it’s best not to render in direct sunlight, as this is the most probable cause of the render drying out too fast. Render that has dried out too fast can result in cracking and damage, or even a patchy finish.

An old trick that lots of renderers use is to start before the sun has fully risen (many of our installers start out at around 5am!). Start by applying render on a wall that is not exposed to sunlight, and follow the sun around the building working on the walls that are in the shade. This allows you to continue to work in sunny weather, but prevents issues with the render drying out too fast in direct sunlight (it’s also much better for the installer to be out of the sun anyway – safety first!).

Another way to avoid cracking when the weather conditions for rendering are not ideal is to wet the walls before application, or even better apply the Water Based Primer. This primer limits the absorptive capacity of the substrate. During hot weather, ordinary masonry will have dried out and the absorptive capacity of the substrate will be extremely high. Using a primer ensures that the substrate is prevented from absorbing too much water from the render and causing it to crack during the curing process.

For our thin coat render systems, we always advise the use of Fibreglass Mesh embedded within the basecoat layer. We also advise that mesh is embedded within the first layer of Monocouche Render. This is even more essential when the weather conditions for rendering are not ideal, as the Fibreglass Mesh increases the tensile strength of the whole system, so when the render shrinks during the process of drying, the mesh will help to prevent cracking.

Rendering in Cold Weather

Cold weather means that the render may not dry out fast enough. If this is the case, the render may retain moisture for too long and thus become susceptible to damage from this trapped moisture.

Mineral Render is a great option when it comes to applying thin coat render in colder conditions. This is because it’s a dry-mix render and is therefore much more quick-drying than our ready-to-use thin coat renders. It also has much faster drying times than our Monocouche Scratch Render because this is applied in a very thick layer, which increases its curing time.

Using a Render Accelerator in the colder weather is also excellent if you are installing our Silicone Silicate, Silicone or Acrylic Renders. Simply mix in 100ml of Render Accelerator per 25kg bucket of render and you can gain faster drying times, reduced cracking and water retention in the winter.

When it comes to the basecoat layer, the Winter Adhesive has been specifically designed for use in colder temperatures when the weather conditions for rendering are not ideal – it can be used even down to zero degrees. When you use the Winter Adhesive, you are ensuring that you have a strong and crack-free surface onto which you can apply your thin coat renders. By doing this, you increase your chances of achieving a great finish – even when the weather is not ideal!

We upload every Tuesday and Thursday, so stay tuned for more content all about our render and EWI systems.

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sand and cement render high performance blocks

Sand and Cement Render on High Performance Blocks

Cracked Sand and Cement Render on AAC Blocks

We recently came across a case where a customer had sand and cement render installed on their home which was built with high performance blocks. High performance blockwork, such as autoclaved aerated concrete (AAC), is a lightweight concrete building material. These blocks are known as high performance because they offer insulating capabilities, fire and mould resistance and are also highly breathable.

The issue with using sand and cement render with this kind of blockwork is that sand and cement render is very old fashioned and lacks any sort of breathability and flexibility. The contrast between the two materials is that by using sand and cement render you are essentially using a low-performance render on a high performance substrate. The result is therefore excessive cracks in the render, as this customer unfortunately discovered. (see photos below!)

Hairline cracks in sand and cement render around doors and windows:

An array of cracks within the sand and cement render:

Render for High Performance Blocks

Because high performance blockwork is so lightweight and breathable, using a really solid and hard material such as sand and cement is not suitable. Instead, you need a lightweight and breathable material – such as our Lightweight Basecoat. This is because the Lightweight Basecoat contains lime and perlite, so it’s strong but most importantly flexible and breathable; therefore it is completely ideal for high performance blocks because as the soft blockwork moves with the building, so will the basecoat.

Once you’ve applied the Lightweight Basecoat to the high performance blocks, leave it to set for 24-48 hours and then prime the basecoat using our SiSi Render Primer. This will ensure a strong adhesion of the Silicone Render to the basecoat.

Thin Coat Renders for High Performance Blocks

Silicone Render is ideal for use on lightweight, high-performance blockwork instead of a sand and cement render (check out our blog on ‘Sand and Cement Render vs. Thin Coat Render’ for more information!). It’s a thin coat render and is therefore extremely breathable, flexible and crack resistant. This is the ideal render if you are looking for something that will maintain a clean and fresh appearance for years to come because Silicone Render is self cleaning.

An alternative to the Silicone Render is our Silicone Silicate render. This is very similar, except it’s a hybrid-silicone render; it therefore lacks the same level of self cleaning but the presence of silicone within the formula means that Silicone Silicate is also very breathable.

In some parts of the UK, poor weather means that installing a thin coat render is challenging. Our Mineral Render is extremely fast drying and offers the same breathability and flexbility as the Silicone or Silicone Silicate Renders. Mineral Render only needs painting with Silicone Paint afterwards to seal it in and protect it against weathering.

Paint Finishes on High Performance Blocks

Many people opt for a sand and cement render so that it can be painted directly after application and setting. As we know, when using high performance blockwork sand and cement render will crack, and your perfect painted finish will result in hairline cracks.

If a paint finish is your desired outcome, then using Silicone Paint on top of our Lightweight Basecoat is a brilliant alternative to sand and cement render on high performance blocks. Using Silicone Paint can achieve a smooth finish that is very easy to refresh and re-paint as time goes on.

Before you can apply the Silicone Paint to the substrate, you will need to do a ‘tight coat’ of the Lightweight Basecoat. This is where you apply a thin layer which is then either rubbed up or sponged to give the desired finish before painting.

Silicone Paint is the most ideal paint for use on high performance blockwork because it is hydrophobic and breathable, and will therefore work in harmony with the breathable high performance blocks. 

You can also check out our blog post on how to render ICF for an idea of how you would go about rendering different high performance substrates!

Recap – Suitable Render Products for High Performance Blocks:

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How to Remove Render

What is ETICS Render Remover?

We love to bring to our customers new and exciting products that will genuinely be of use on-site. Among these is our ETICS Render Remover, because it’s a bit of a lifesaver when it comes to cleaning up and making sure that there’s no damage to the property during installation!

When working on-site, it’s practically impossible to ensure that the property remains immaculately clean. It’s inevitable that render will be dropped on areas such as patios, pavements, windows and doors, leaving a worrying stain. ETICS Render Remover is a fast-acting chemical cleaner which effectively breaks down spilled, dried out render. We always recommend that installers take precautions to protect these exposed areas by using window protection film and other protective covers, however accidents happen, and here’s what to do when they do!

How to use ETICS Render Remover

Something that makes this a really appealing product is the fact that it’s so easy to use. ETICS Render Remover is highly versatile, as you can use it on a range of substrates including metal, plastic and rubber, glass, uPVC, brick, concrete and tarmac. It’s perfectly safe to use, posing no threat to workers and, importantly, it’s not hazardous to the environment!

To use the ETICS Render Remover, you can simply wet the stain using water and remove any large chunks of render, then blob the ETICS directly onto the stain, leave it for 10-20 minutes and bob’s your uncle! You can re-apply the render cleaner as many times as you like if you’ve got some particularly tough stains to get rid of.

Another convenient use of the ETICS Render Remover is by using it in combination with a jet wash! For each process, whether it’s by hand or by jet wash, once you’re happy that the stain has been fully removed make sure you wash away any remaining ETICS with clean water.

ETICS Render Remover comes in both a gel and a liquid. The gel is particularly useful if you’ve managed to spill render on a vertical surface such as a window, because the ETICS needs to be able to sit on the surface of the stain for 10 minutes to work and the gel prevents it from just sliding off.

EWI Pro Materials and ETICS Render Remover

The great thing about the ETICS is that you can use it for a wide range of product stains and still get great results. For example, you can use the ETICS with our thin coat renders: Silicone, Silicone-Silicate, Acrylic and Mineral Renders. It’s also great for use with our adhesives and basecoats, with Monocouche Scratch Render and with our Silicone Paints!  

ETICS Render Remover – An Overview

  • Use it on your tools to get rid of damaging stains
  • Use it at the end of a job to present a nice clean finish to your clients and bring in some great reviews
  • Use it to clean up the edges of your render to go that extra mile and be high quality
  • Virtually no risk to the finished work
  • Quick and easy to use
  • Versatile – use on a range of substrates and to clean away a range of products
  • An environmentally friendly product

Stay tuned for more content! We upload new blog posts every Tuesday and Thursday all about our products, with technical advice and answering customer’s FAQ’s!

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What are Brick Slips?

Brick Slips Cater to Every Taste

It often comes as a surprise to customers that our render finishes aren’t the only finish that we offer here at EWI store. We offer brick slips in a wide range of different colours, including:

With external wall insulation, you cannot use actual bricks due to the fact that the system wouldn’t withstand the weight. Brick slips are therefore fantastic if you need to recreate the original look of your property. This could be the case for many people who are installing EWI somewhere where it is required that you maintain the character of the property or even if you would just rather have a brick finish rather than a render finish.

The great thing about them is that they can really improve the look of the property, especially if the original brickwork is looking a bit tired and worn – the brick slips offer a total face lift, and with the added benefits of EWI thrown in it’s a bit of a no brainer.

Brick slips are fantastic because they are so realistic looking, but they are also completely flexible, weatherproof and UV resistant (so the colour won’t fade over time!). The EWI acrylic brick slips are almost completely mineral based, made from a mixture of assorted quartz sands and a binding agent.

Rather than being made of the traditional mortar, our brick slips offer vapour permeability, making them perfect for use as part of an EWI system. They are also impact resistant and are easily washable, so very easy to maintain.

How are Brick Slips Installed?

Our brick slips are really simple to install. We offer our special adhesive which comes in five different colours and is designed specifically for use with the brick slips to create a long lasting, reliable bond between the brick slips and the substrate.

When installing brick slips on top of an external wall insulation system, you would first install the basecoat and mesh on top of the insulation boards. The brick slips are then applied on top of this; you must use a notched trowel to apply the special brick slip adhesive to an area of the substrate (approximately 1m2). You then apply the brick slips to the adhesive, forming a standard brick pattern by staggering the bricks and leaving a space of around 10mm between each brick vertically and horizontally, which will give a really realistic effect. You can very easily bend the brick slips around corners because of their flexibility, or you can cut them to the desired shape.

Brick Slips can be used Internally  

We recently had a really enthusiastic customer who wanted to purchase brick slips to go around the chimney breast inside her living room. It’s great to see creative home design, and because of the fact that we offer brick slips in both white and black you could really easily achieve a chic and modern look inside your property.

We think that installing our brick slips is super easy and can definitely be done internally as a DIY job for your chimney breast, your kitchen splash back or even as a statement wall. They would also look great in apartment block entryways.

Where can I buy Brick Slips?

You can buy flexible and durable brick slips via EWI Store! We offer a wide range of finishes, including brick slip corners.

If you have any further questions regarding our brick slip finishes, comment down below or contact our sales team! 

Looking for more inspiration on how to make your property look great on the outside? Check out our blog on render design features for some great ideas.


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building regulations and U-values, EWI, external wall insulation and U values

External Insulation for Passive Houses?

What is a Passive House?

Passive Houses and external wall insulation are two hot topics within the energy efficiency and insulation industries. Passive House is a construction concept that originally began in Germany; initially coined ‘passivhaus,’ it is generally known as an energy efficient, environmentally friendly house that practically requires no heating. The building is constructed in such a way that it is tightly sealed in a thermal envelope which allows very little heat to escape, so that essentially a room can be warmed simply by light from the sun, body heat or the heat from small electrical appliances. 

There are three things that a house needs to achieve before it can be considered a Passive House:

  • A Passive House needs to have primary energy demands (such as warm water, heating, house appliances) lower than 120 kWh/m2a
  • A Passive House needs to have heating demands lower than 15 kWh per square meter annually.
  • A Passive House must pass a pressure test and the pressure must be limited to 50 Pascals with the pressure differential not exceeding 0.6 times a room’s volume per hour.

A Passive House has a high level of insulation. That includes the doors, windows (triple glazed), walls, floors and roof. However, as we know, houses need proper ventilation – therefore Passive Houses also require a mechanical ventilation system.

Excellent indoor air quality is a characteristic that Passive Houses possess, and this is achieved through the mechanical ventilator exchanging the air from inside with the air from outside. These are great for being energy efficient, because during the process of heat exchange the ventilators can transfer the fresh air into the room at the same time as heating up/cooling down the fresh air. This means that Passive Houses are able to exist without the frequent or constant use of conventional heating systems, many only have one radiator in the bathroom for drying off towels.

External Wall Insulation on Passive Houses

So, as previously mentioned, Passive Houses require an outstanding amount of insulation; typically a Passive House wall will have a U-value of 0.15m/m2k. Luckily, external wall insulation would do the job perfectly if you get it at the right thickness. EPS, Mineral Wool and Wood Fibre have low enough U-values to be able to obtain the required level of insulation for a passive house.

However, the insulation needs to be totally sealed against thermal bridging– which means absolutely no gaps. This is because gaps in the insulation break the thermal envelope and, especially in highly insulated houses, reduce the effectiveness of the insulation. Thermal Bridging can cause damp and condensation – which can be far more detrimental to a passive house than a regular house.

Which EWI System is Best for a Passive House?

To achieve Passive House U-values on a 215mm solid brick wall, 270mm of Mineral Wool would be required. Mineral Wool is highly breathable so it’s great for a Passive House construction where ventilation and air quality are key in order to prevent damp. Due to the fact that Mineral Wool is made of a renewable material (volcanic rock), it’s also in keeping with the ethos of the Passive House. Rockwool is made by spinning volcanic rock in a furnace at a high temperature to create a cotton candy-like texture, and then it’s compressed into dense, flat insulation boards. Rock is not a very good heat conductor, and the fibres from the spun rock provide air pockets, which is what makes it a great insulation material.

In keeping with the Passive House rules, the EWI-225 Premium Adhesive, designed for use in Rockwool systems, is also ideal because it is breathable, strong and waterproof.

To finish off the system, for a Passive House you will want to use a Silicone Render. Again, this works really well in conjunction with the Rockwool system because of its breathability. Silicone Render is hydrophobic (water repelling) so moisture will essentially bounce off its surface, safeguarding the system against damp.

Wood Fibre Insulation for Passive Houses

Our most environmentally friendly insulation material is our Wood Fibre insulation, which we source from Pavatex. To achieve Passive House U-values with Wood Fibre on a 215mm solid brick wall, you would need 240mm of insulation. Wood Fibre is a highly versatile insulation material, offering excellent thermal performance. Our Wood Fibre insulation is completely recyclable and holds the prestigious title of being NaturePlus certified. The fact that this insulation is so highly renewable and environmentally friendly means that really it’s ideal for Passive Houses where environmental consciousness is at the forefront of the building design. Passive Houses also require a high level of breathability, and Wood Fibre is the most recommended insulation material to achieve this.

Building a Passive House is a highly technical procedure, and external wall insulation could definitely play a part in helping to mimic the Passive House standards. Our sales team are experts on all of our products and will be able to give you any technical advice about their technical specifications and usage. Feel free to contact us for any questions regarding our materials or get yourself a free materials quote using our calculator!

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The Best Masonry Paint? Silicone Paint

What is Silicone Paint?

We often receive enquiries about our Silicone Paint from customers who are looking for high quality masonry paints, or who are interested in re-rendering their properties. The main questions that they ask tend to be about what the difference is between Silicone Paint and Silicone Render; and what is Silicone Paint for? Well, we hope to answer all of your questions in this blog post!

Silicone Paint is a breathable, hydrophobic topcoat finish which is great for applying over the top of an existing render as you would a normal masonry paint. It’s resistant to water, environmental pollutants and organic growth, so it would be perfect if you live in a busy, built up city or if you live in a humid, rainy environment where your render is susceptible to organic overgrowth.  

What is the difference between Silicone Paint and Silicone Render?

It speaks for itself really that Silicone Paint is a masonry paint topcoat, whilst the Silicone Render is a render finish. The only similarities between them are the fact that they both contain Silicone, which provides numerous benefits – but we’ll come to that later!

Our thin coat renders come in different grain sizes ranging from 1mm to 3mm; in contrast, our Silicone Paint does not come in different grain sizes, it’s completely smooth so can be applied on top of the existing render without disrupting the texture.

Silicone Paint is designed to be used as either a masonry paint topcoat to seal in the render underneath (e.g. for use with our Mineral Render), or it can be used as a means of refreshing your render finish if it needs a bit of a spruce further down the line.

Silicone Render is hydrophobic, which means that it repels dirt and organic growth. However, after many years even a render with these capabilities can look tired. This is where Silicone Paint comes in really handy as part of your render aftercare because it is also hydrophobic – so it not only refreshes the render but adds another protective layer to top up its lifespan.

Why use a Silicone Masonry Paint?

Silicone Paint provides a super breathable finish, so as part of a render or EWI system it works particularly well. As we know, ingress of water and moisture is detrimental to rendered properties and to external wall insulation. For EWI, if water enters the system it can reduce its thermal capabilities and the water can damage the system during the freezing and thawing process. Ingress of water within a render-only system is particularly bad,  allowing the water to cause damage to the render. It can seep into the walls of the property and cause damp patches on the internal walls, especially with solid wall properties.

The Silicone Paint acts as a protective barrier against this problem. Its breathability allows water and moisture to escape through the surface of the paint and it prevents moisture from passing through, because the silicone within the paint repels water vapour. Because of its vapour permeability, Silicone Paint is also frostproof – frost will not cause damage by settling on its surface or within the actual masonry paint itself.

We always recommend to our customers that our Mineral Render should be sealed in with a high performance masonry paint such as Silicone Paint. Mineral Render is our fastest-drying render which is perfect for cold climates, however its ingredients means that if it’s exposed to the elements for too long it can be susceptible to lime bloom. This is why it’s necessary to apply Silicone Paint over the top of it, to prevent water from passing through to the render underneath and causing the formation of lime bloom.

Silicone Paint can be Matched to the Coloured Render Underneath!

If you’ve used one of our coloured renders, then you can very easily buy a Silicone Paint in exactly the same colour to match it to the existing render. We offer a same-day colour mixing service using our render colour machine which can tint your Silicone Paint into thousands of different colours, so even if your render does not come from EWI Pro we will be able to match up the paint for you!

Silicone Paint is Great for Interiors and Exteriors!

We’ve previously talked a lot about render and how Silicone Paint can be used as a masonry paint in addition to your render finish as a protective topcoat, however many people aren’t aware that Silicone Paint can be used for interiors as well as exteriors!

We’ve heard of people using Silicone Paint in their bathrooms, because it’s a really waterproof paint and is perfect for the humid environment of a bathroom. We’ve also heard of people who have previously suffered with problems of damp in their home, and have used Silicone Paint as a future deterrent because of its breathability. One of our members of staff has also used silicone paint on his garden wall to prevent organic growth. We think all of the above uses are great ways to utilise Silicone Paint!

Get In Touch to Buy Silicone Paint!

We’re always happy to answer any further questions about our products, so give us a call if you are interested in using Silicone Paint for your home. We can work out exactly how much you’ll need depending on the square meterage of your property.


We upload a new blog post every Tuesday and Thursday, so stay tuned for more product information and technical advice!

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EWI Funding in Scotland (HEEPS)

Homeowners in Scotland can now claim financial funding for EWI! Here at EWI Store, we’re all about helping homeowners increase the energy efficiency of their property through external wall insulation. Unfortunately for many people the upfront cost of installation just isn’t viable, so living with higher energy bills becomes something they have no choice but to put up with.

Fortunately for those living in Scotland, the HEEPS scheme may be able to help! The Scottish government are keen to help homeowners save money on their energy bills by providing funding for a wide range of energy efficiency measures. We’re happy to see that government initiatives are recognising the need for reduced energy bills for homeowners, especially when considering the current UK energy crisis and the resulting high energy tariff rates (our friends over at The GreenAge talk a lot about this topic!).

What is the HEEPS Funding Scheme for External Wall Insulation?

The Home Energy Efficiency Programmes Scotland (HEEPS) loan is open to applications and aims to help owners to improve the energy efficiency of their homes with funding for a number of energy efficiency measures. These include energy efficiency improvements such as insulation, glazing and boilers; home renewables systems such as solar panels; and energy storage systems such as storage heaters.

The great thing is that the funding covers external wall insulation and is not limited to cavity wall, so if you live in a solid wall property, or cavity wall insulation is simply not available for you, then this grant is open to you!

How Does the EWI in Scotland Funding Work?

The HEEPS scheme is divided into loans and cashback. Under the HEEPS loan scheme, you can borrow up to £10,000 interest-free in order to carry out external wall insulation on your property. Cashback funding is only available if you apply for and go on to claim a loan; cashback funding therefore cannot be applied for separately. For external wall insulation you can claim £2,500 in cashback on a £10,000 loan.

The repayments for a £10,000 loan are completely interest-free, and are to be paid back over the course of up to 12 years. When you consider the amount of money you’ll be saving after external wall insulation, the money you would have paid towards energy bills will essentially go towards the repayments of this loan.  

How do I get the HEEPS loan?

In order to get the HEEPS loan, you need to contact Home Energy Scotland personally, who will give you advice on the best energy saving solution for your property. You will not be able to get your installer to apply on your behalf, as the scheme will need to speak to you personally before sending out the application form directly to you. This is because the scheme is managed by the Energy Saving Trust, who are experts in energy saving advice for homeowners and therefore will ensure that the funding is going towards the right measures for the right people.

People who are eligible for the EWI funding in Scotland include homeowners and registered private sector landlords, however this is restricted to ‘natural persons,’ which effectively means landlords that are not registered as a company. As well as this, in some circumstances landlords can apply for funding on up to 3 properties that are currently occupied by one or more tenants. More information on the scheme can be found via the Energy Saving Trust!

Energy Saving and External Wall Insulation

External wall insulation can benefit homeowners in many ways. Not only does EWI reduce energy bills, it will keep your home warmer in the winter and cooler in the summer. EWI can also reduce problems with damp, improve the outward facade of the property and increase the lifespan of the property’s external walls by protecting against weathering.

EWI is an energy saving measure that is open not only to owners of solid wall properties but also those who own timber frame houses, steel frame houses and more. We advocate the installation of EWI because it is so versatile and genuinely worthwhile.

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Stay tuned for more content! We upload a new blog post every Tuesday and Thursday, all about our products and systems, with technical advice and answering customer’s FAQ’s!

Why Use Lime-Based Renders?

An Introduction to Lime

The use of Lime in building materials has a long history, dating back to the times of the Roman Empire, when lime was used for construction purposes such as mortars and render finishes. It continued to be used until the nineteenth century until Portland Cement and other cements came onto the scene, when the use of lime-based materials began to decline.

Lime is still frequently associated with vernacular buildings within areas in the south of England along The Jurassic Coast, and in places such as Bath and the Cotswolds. Lime has also recently experienced a bit of a revival in modern building and construction for use in modern renders.

So why would you want to use lime as a component in your render finish for your EWI system?

The Use of Lime in Building Materials

Lime is considered to be a ‘healthier’ building material in comparison to Gypsum and cement-based products. This is because quicklime absorbs carbon dioxide during the setting process of carbonation – otherwise known as the lime cycle. Essentially, the lime cycle is the hardening process of lime mortar and lime wash when water evaporates from lime putty and the lime reacts with the carbon dioxide present within rain water.

During this repeated cycle, the lime experiences a repeated chemical change until finally it is converted back to calcium carbonate (which is basically the original limestone). This is a slow process, but essentially what this means is that your lime mortar will eventually get stronger as time goes by. This process creates the oldest and most flexible and breathable form of lime.  

Another reason that lime is frequently used in mortars and building materials (e.g. our Lightweight Basecoat) is due to the fact that lime is a caustic. This primarily means that it has disinfectant qualities – lime mortars, renders and washes have been used to create hygienic and comfortable surfaces for buildings for thousands of years.

Lime can also be produced on a small scale; it can be produced in small quantities to meet primary demands, therefore saving energy and resources. With reference to the use of lime in the Roman era, and the gradual hardening of lime during the lime cycle – lime-based renders are also durable and have historically stood the test of time, which means that reproduction of materials for repairs is less necessary. It’s therefore a favourable option for those who are environmentally conscious but also want a durable render facade.

Lime-Based Renders and EWI systems

Lime as a component in building materials adds the benefit of breathability and vapour permeability; the greater the amount of pure lime in the building materials, the better the breathability. Because lime is porous, it absorbs and releases humidity (it breathes), therefore helping to maintain the thermal comfort of a building. This makes it fantastic for older buildings by allowing the building to breathe, and also in external wall insulation systems.

Lime-based render is an excellent addition when used in external solid wall insulation systems. This is because the breathability of lime means that it can prevent ingress of moisture, which as we know would disrupt the effectiveness of the system. This is because any kind of moisture content prevents the insulation material from retaining heat properly.  

Due to its small particle size, lime can fill minute voids within a surface, which makes it a great adhesive in comparison to cement which has large particles. Due to this, lime also binds gently to background materials, allowing for flexibility and crack resistance – although lime-based renders are more likely to develop fine, hairline cracks in comparison to larger cracks within cement-based renders.

When installing lime-based render, it cannot be applied during freezing temperatures, as this will delay the carbonation process and the render can take up to a month to properly set which may cause the render to fail. Lime-based render must also be treated with a breathable finish such as lime wash or silicone paint to protect the underlying render.

Looking for more information? Here are a couple of blogs all about when a basecoat that contains lime would be ideal…

‘Applying Coloured Render to Thermalite Blocks’

‘Sand and Cement Render on High Performance Blocks’

Stay tuned for more blog content! We upload every Tuesday and Thursday all about our EWI and render systems, answering FAQ’s and giving full and detailed product guides.

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Coming soon!