Monthly Archives: May 2018

Can you use EWI Pro materials with other insulation boards?

Here at EWI Store, we provide customers with a whole-system approach to external wall insulation. We sell all the products required for the job, and we can put you in touch with any of our approved installers in your area.

However, there are instances where customers want to use our systems but they wish to swap out the insulation board with an alternative insulation board to the ones that we offer (Mineral Wool, EPS and Wood Fibre). It could be that the customer would prefer to use a 100% natural insulation material such as cork insulation boards, or they would like to use Kingspan K5 insulation boards because a thinner amount is required to achieve the same thermal performance.

We wouldn’t generally advise that this is the best approach, because our external wall insulation systems are designed so that the products are technically engineered to work in conjunction with each other. By using an alternative insulation board, you may be compromising the quality and strength of the system.

However, this isn’t to say that it can’t be done. You can use EWI Pro external wall insulation systems with other insulation boards. Nevertheless, there are a few things that we would recommend you do to ensure that the system is totally secure.

Using EWI Pro adhesives with alternative insulation boards

Whilst it is possible to use other insulation boards, we suggest that you do not stray too far away by using other adhesive materials. We would recommend that you stick to EWI Pro materials for the rest of the installation. By doing this you’ll be better off in the long run because the rest of the materials in the system will work properly in conjunction with each other (as they are designed to) and it will minimise any risks or problems further down the line.

When using an alternative insulation board, we encourage the use of the EWI-225 Premium Adhesive to secure the insulation boards to the substrate. The type of adhesive that you use does usually depend upon how heavy the insulation material is. However, it’s better to be safe than sorry – so in order to completely ensure that the alternative insulation boards will adhere to the substrate properly, it is imperative that you use our extra strong adhesive.

The 225 Premium Adhesive has been designed with EWI Pro insulation systems in mind, most especially Rockwool insulation boards which tend to be a bit more heavy than EPS. The Premium Adhesive is extra strong, and contains strands of fiberglass embedded into the material. This basically means that the tensile strength of the adhesive is overall much higher than other alternative adhesives. So you can be confident that it will bond to the alternative type of insulation board, and ensure that it is firmly secured to the substrate.

The EWI Pro adhesives are also highly breathable. So when installed properly, the EWI-225 will support the system against the dangers of water ingress.

As well as this, by using the EWI-225 any EWI Pro renders applied as a top coat will bond to the adhesive correctly. This is again because our renders have been designed be applied on top of EWI Pro materials. Applying our renders to any other type of adhesive may affect the success of their application and their longevity.

Using EWI Pro Mechanical Fixings with other insulation boards

Another suggestion that we would make when you are using an alternative insulation material is the type of mechanical fixings that you use.

Our Mineral Wool boards are much heavier than EPS, so we advise that installers use metal fixings because these are much stronger than plastic.

For alternative insulation materials, we therefore recommend that you follow the same guidelines and use metal fixings for added strength and security. Metal fixings also require the application of EPS thermo dowel caps to the heads of the fixings to prevent thermal bridging. By following these guidelines, you’ll be giving your external wall insulation system an added layer of security.

Using EWI Pro Silicone Render with other insulation boards

The final step in the system is choosing which render would suit the insulation system best. We would advocate our silicone render when using alternative insulation boards. This is because silicone render is our premium render, with unrivalled breathability and strength. Basically, by using a silicone render you are adding an entirely waterproof and vapour permeable layer to the exterior of the EWI system.

Water ingress is the worst possible occurrence for an external wall insulation system. If your insulation boards lack breathability, then any water vapour collecting within the system can compromise how well it functions (its ability to insulate), and it can also mean that over time the system becomes improperly secured to the substrate. If you were to use a non-breathable render, it would trap any moisture within the system and could compromise its structural integrity. Using breathable materials such as our silicone render is therefore your safest bet and will reinforce the system’s ability to breathe and function.

If you have any further questions, we are always on hand to give technical support and advice so just give us a call and we would be happy to help! Alternatively, if you are looking for an external wall insulation installer then we have a whole list of approved installers who we can put you in touch with!

 

How Do I Look After my Render Finish?

The trick to a long-lasting render finish is attentive aftercare. Here at EWI store, we always like to see how great our renders look once installed, however we understand that it doesn’t just stop there. Customers want to be able to maintain the fresh, brand new facade that they have spent their time and money on, and actually taking good care of your render finish will ensure its longevity and could prevent problems from occurring down the line.

So, we’ve put together a render maintenance and aftercare guide for all of our EWI Pro renders. This may also be useful for those who are looking into choosing a render and are deciding on which ones would suit their tastes best.

In any render aftercare, always check for cracks. Any cracks that are wider than the width of a credit card should be investigated further and repaired by a professional tradesman. Typically, cracks might appear around windows and doors. It is somewhat unlikely that you will experience cracking when using our renders, as our monocouche is reinforced with fibreglass mesh to increase its flexibility and strength, and our thin coat renders are all very flexible. Nevertheless, if this occurs then you should seek advice from a professional tradesman or give us a call for further advice.

Furthermore, to ensure the long lifespan of any type of render we advise that as part of your render aftercare you keep any plant life below the level of the render. Plants, trees and climbing plants may look nice, but these can cause staining to light-coloured renders and could increase the amount of render maintenance required.

Monocouche Scratch Render Aftercare and Maintenance

It’s important to take good care of your render finish if you want it to last its full lifetime. We recommend that for our monocouche scratch render, your render aftercare should involve giving it a gentle pressure wash or hand wash every 6-12 months (or just when it’s looking a bit grubby). This should alleviate the need to use harsh cleaning chemicals further down the line (which could break down the render). This will also eliminate any build-up of dirt, giving you a sparkling and pleasing finish!

When cleaning your monocouche scratch render, it is imperative that your render has been allowed to set for at least 28 days. You shouldn’t even really need to clean your render at this stage, and therefore we advise that you refrain from any serious render maintenance during this time period. This is because the monocouche render takes around 28 days (or more) to reach optimum strength. So, if you are a bit over eager and you give it a big old power wash before it’s fully cured, then you could do some real damage and end up spending more money trying to get it fixed.

Once you’ve passed this 28+ day period, if you’re keen to give your render a wash down then we suggest that you first hose down the render to remove any surface dirt. When hosing down your render, we recommend you use a fan tip rather than a direct needlepoint spray as this would be too harsh and could weaken the render. After this, using a brush, apply hot soapy water to any areas that are particularly affected by dirt. Make sure that you rinse off the detergent as you go.

If your monocouche render is showing signs of mould growth, then the best thing to do is to apply the EWI-360 Fungicidal Wash. The active ingredient in our Fungicidal Wash is Benzalkanium Chloride, a proven biocide.This is really effective aftercare treatment as it removes mould and organic growth. You can apply this with a sponge, cloth or knapsack spray, then leave it to dry for 24 hours.

Silicone/Silicone Silicate Render Aftercare and Maintenance

Because Silicone render is hydrophobic, it should resist organic growth really effectively, which means that it requires very little maintenance over the course of its lifetime. For Silicone render, it’s best to just clean it as and when needed, as it’s unlikely that the render will show much dirt. However, lighter colours are more likely to be susceptible to showing dirt, and if this is the case then the best method for cleaning the render is to use soapy water and a sponge, or a low-pressure jet wash. Do not use any acid cleaners as this could damage the render.

If the level of render maintenance required is of a higher level, it is possible to paint over the render surface with a silicone paint. If you’ve used an EWI Pro silicone render then you can easily match the silicone paint to the render. You’ll need to give the render surface a gentle jet wash, leave to dry and then paint over. Applying silicone paint should reinforce the hydrophobic properties of the render and extend its lifetime. We do recommend that to achieve the best results, you should hire a professional tradesman who is familiar with the materials to carry this out.

Again, in the event that mould growth appears, this should be treated with EWI-360 Fungicidal Wash.

Acrylic Render Aftercare and Maintenance

Acrylic render does not possess the same hydrophobic properties as silicone based renders do. Therefore, you may find that grime and pollution affect the appearance of the render over time. As well as this, if you live in an especially wet climate then damp and mould could appear on the exterior walls of your property. In general, the larger the grain size that you go for the more likely it is that the render will retain dirt.

In these instances, you can use a stiff bristled brush and warm water with a household detergent – or if the exterior is particularly grimy a low-pressure jet wash should do the trick. As with monocouche, you should look into giving your render a gentle wash every year or so. If you are experiencing heavy staining on your render then we recommend that really the only option for you is to paint over the facade with the EWI-005 Silicone Paint.

Mineral Render Aftercare and Maintenance

Aftercare and maintenance for mineral render is slightly different. As we know, mineral render requires painting with silicone paint after it has been applied in order to prevent lime bloom.This occurs when the render is subjected to damp conditions or low temperatures while it is still curing. The purpose of applying silicone paint over the top of the mineral render is to seal the render against the elements- silicone paint is hydrophobic, and therefore prevents lime bloom by allowing water to run off the surface of the render and reinforce this protective layer.

If your render is not painted over (when it should have been) then your mineral render finish will be highly susceptible to Lime Bloom which is a pain to get rid of, although there are various render cleaners on the market aimed at getting rid of it. Any signs of lightening or patchiness in a fully cured render is generally an indicator that it has been affected by Lime Bloom.

However, because of the protection that silicone paint provides, Lime Bloom shouldn’t be an issue and your render aftercare and maintenance will generally be the same as silicone render – remove any dirt with a light jet wash and/or soapy water and a sponge. As well as this, if you feel that your render finish needs a bit of a refresh later down the line then you can apply a new layer of silicone paint to achieve a brand new finish and reinforce this protective layer.

Pebbledash Aftercare and Maintenance

Pebbledash is meant to be a really hard-wearing render finish, but this doesn’t exempt it from problems such as mould and organic growth. We recommend that the best course of action is to first try and remove the worst of it with a brush and water, but be really careful not to scrub too hard in case the stones fall off. You should then spray the rest with the EWI-360 Fungicidal Wash and leave it on for 24 hours to work its magic. After 24 hours, and in the unlikely event that there is any overgrowth left over after this, then you can again attempt to take off the remaining with a brush and soapy water.

With pebbledash, you may find that over time the stones start to drop off the wall. This is due to weathering, and can really affect the aesthetics of your render finish. Falling stones also leave the render even more exposed to the weather. Unfortunately, you cannot patch repair pebbledash, and painting over it will not look fab.

If you are really keen on the pebbledash look, then you can get it re-rendered using the EWI-235 Dash Receiver which is more durable than ordinary cement-mix used for pebbledash – so would last a lot longer. Otherwise, you can read about your other options in our previous blog post: ‘how do I replace my pebbledash with coloured render?’.

Hopefully this guide was useful, but if you do have any further questions then don’t hesitate to ask by leaving a comment or giving us a call. Please do remember that this is only meant as a guide upon which customers can act as they see fit!

Want to know more about our range of renders? Check out the following blog posts:

render carrier board and thin coat renders

Render Carrier Boards: The Ultimate Guide

Render carrier boards, sometimes referred to as sheathing boards, are typically made from cement boards, cement particle (CP) boards, magnesium oxide (MgO) boards or even gypsum.  

Render carrier boards provide a durable backing surface for thin coat render systems to be applied to. These boards are normally applied to a carrying substrate such as treated timber battens or a lightweight steel frame, and are common place in large residential and commercial projects.

For more traditional renders, i.e. a monocouche scratch finish or a lime render finish; a thicker board such as a Celenit wood wool board should be used. This is because of the extra weight a traditional render system has.

All of these boards have similar characteristics in terms of application, but all have subtle differences in terms of performance. Some boards are easier to cut, as they can be “scored and snapped”. Some offer class A1 non-combustibility, and some offer good impact resistance. They will all provide some weather protection before they are rendered, and in some cases can be left exposed for up to a year.

Here is a list of the most common boards for thin coat render systems and their features:

 

Board Type Composition A1 non-combustible “Score & snap” EWI-Pro Compatible
Modelpan MgO Yes Yes Yes
Siniat Weather Defence Gypsum Yes (above 18m) Yes Yes
Knauf Aquapanel Cement Yes Yes Yes
RCM Renderflex Fibre Cement No (A2) No Yes
Resistant Multi-rend MgO Yes Yes Yes
Rendaboard MgO Yes No Yes
Siniat Bluclad Calcium Silicate Board No (A2) No Yes
Fermacell Powerpanel H2O Cement Yes Yes Yes
Econic MgO Yes Yes Yes
Magply MgO Yes Yes Yes

 

Render carrier boards provide a solid, durable surface that can withstand the extreme weathering effects of wind, rain and snow. They can provide an impact-resistant barrier, and most render carrier boards don’t rot or swell when they come into contact with water, so they survive a long time even when located on the exterior of the property.  

However, some boards are not as structurally stable as others and depending upon the applications manufacturers will sometimes advise leaving a space between joints – so always check the specification. At EWI-Pro, we recommend taping all joints.

Applying render to a render carrier board provides a fantastic looking finish, but also offers a further level of protection to the boards. So how do you go about it?

Applying the basecoat to the render carrier board

The first step in any thin coat render system is the basecoat layer. Applying the basecoat to the cement board is relatively easy – we recommend using the EWI-225 Premium Adhesive. The EWI-225 is a premium adhesive which comes as a dry mix and therefore must be mixed with 7 litres of clean, potable water prior to application. Please see our product data sheet for more information about how to prepare the adhesive for use. 

Once the adhesive has been mixed with water and the white putty has formed, it needs to be applied to the render carrier board with a notched trowel. We recommend using a 10mm notched trowel, this is the best sized trowel for applying a 6mm layer of adhesive to the render carrier board.

Once the adhesive has been applied it is time to embed the fibreglass mesh within it. The EWI-640 mesh gives the render system strength and flexibility and comes in 50 x 1m.  The mesh needs to be embedded in vertical strips within the adhesive. Each strip must overlap one another by 10cm at each of the edges and must be embedded within the adhesive layer – to embed the fibreglass mesh simply use the flat edge of the notched trowel and draw this up from the bottom of the wall which will pull the adhesive through the holes in the mesh.

Remember the render topcoat is incredibly thin so therefore the basecoat layer needs to be completely smooth before applying the render. If you have embedded the mesh and the finish isn’t completely smooth the easiest thing to do is to produce a very wet adhesive mix and apply this to the basecoat before the first layer goes off. This should allow you to create this smooth layer ready for application of the render.

Once the basecoat layer has completely gone off, the EWI-225 Premium Adhesive will be ready for the finishing coat. There is no need to prime the EWI-225 Premium Adhesive unless you are using a particularly dark colour, or if you want to help control the speed at which the render goes off.  

For each finishing coat there is a corresponding primer which can be tinted to match your render colour. Take for example EWI-333, our Silicone Silicate Primer which comes in either 7kg or 21kg buckets. This primer is applied to the basecoat layer using a paintbrush or roller, and is used in conjunction with EWI-040 Silicone Silicate Render. A 7kg bucket of EWI-333 primer covers approximately 20m2 and the 21kg bucket covers approximately 70m2 of wall.

Applying the finishing coat to the render carrier board

It is now time to apply the thin coat render to produce the finished façade! EWI-Pro have a wide range of thin coat renders, most of which are ready-mixed renders except for the EWI-060 Mineral Render. Our thin coat renders come in hundreds of different colours and can be tinted using our special colour tinting equipment to achieve a shade that you like best!

When applying thin coat renders, the thickness of the layer corresponds with the size of the granulate in the render. For example, EWI-040 Silicone Silicate render comes in 4 grain sizes, 1mm, 1.5mm, 2mm and 3mm. The layer of the render should therefore be either 1mm, 1.5mm, 2mm or 3mm depending on the chosen grain size – it should be no thicker!

This is really important to remember, and will ensure a perfect finish. We have heard several reports where people have been applying the render too thick and have not been able to achieve the required finish. With that in mind, apply the render to the render carrier board and basecoat with a trowel, and then spread or pull off all the excess with the trowel. Once you have taken off any excess, leave the render for 5 minutes and use a plastic float to work the render in a circular motion to achieve the final finish.

We have a whole database of approved installers who have undergone our training courses would be able to carry out this work for you, so give us a call if you wish to be put in touch with a trusted local installer!

Applying insulated render to sheathing boards

Many of the boards mentioned in the table above can also be used as sheathing boards. Some manufactures such as RCM have different boards for different applications, while others only offer a cement board for sheathing application.  

These differences occur because some boards are tested for racking strength, some are tested for the use of thin coat render systems and some are tested for both. Using insulation on sheathing boards means an insulation material such as Mineral Wool has been installed onto a suitable sheathing board.

These systems are normally found installed on non-traditional substrates like metal frame or wooden frame buildings. The cement board is installed onto the non-traditional structure using the appropriate fixing method. Once the boards are secured, the insulation system can be applied to this substrate. The insulation boards are securely fixed to the sheathing board (in keeping with the manufacturer’s fixing pattern) using mechanical fixings and adhesive.

EWI-Pro has ETAG (European Technical Approval Guidelines) Certification for this method of installation. Once the insulation is secured, the beading can be applied onto the insulation. This includes the corner beads, stop beads, reveal beads, drip beads and verge trims. Once it is secured using a basecoat mixture, you are then ready to install the reinforcement layer.

When the walls have been basecoated and primed if required, they can be rendered using our decorative renders. The EWI-040 Silicone Silicate and the EWI-075 Silicone Renders are our most popular through-coloured renders and would work very well on a nice and level basecoat.

There you have it – how to apply render and insulation to render carrier boards!

Cavities in render carrier systems

Historically, ventilation voids were mandatory to get NHBC approval and a guarantee. Although this has been counter intuitive on many projects, the practice is common place. Since the Grenfell tragedy, a lot of focus has now been placed on the roll of these voids and whether they are safe.  At EWI Pro, we advocate a breathable insulation fixed directly to the substrate through the sheathing board, which eliminates risk of moisture.

If a stone wool insulation such as Rockwool is used, it is class A1 fire rated and permits the passage of vapour to escape.  For a build up such as this, a pullout test would be required to determine whether any extra fixings per m2 are required.

Some systems also include a provision for ventilation and/or drainage in front of the render carrier board in addition to the ventilation in front of the sheathing board. Again, this is counter intuitive as all the ventilation and air takes away from the thermal performance of the insulation and increases the risk of mould growth.

It is always important to liaise with your EWI provider as early as possible when designing these types of systems. EWI Pro can offer full technical support and can also assist with the specification of your render carrier projects.

 

Why Use a Coloured Render Tester Pot?

Here at EWI Store, coloured render is our specialty. We want all of our customers to be thrilled with the end result of their render finish by making sure that they are fully informed before making their choice of colour – it’s always better to be safe than sorry, especially with a project like this!

It’s often difficult to picture how a colour might appear when it’s in full scale on a building, let alone when you’ve only seen a tiny picture of the colour on a colour chart. Being able to see exactly what colour the render is in real life is essential – that’s why we’ve recently brought out our Coloured Render Tester Pots!

What are the Coloured Render Tester Pots?

Our Coloured Render Tester Pots contain our Silicone Silicate render. They come in a 250ml tub in a default grain size of 1.5mm. We only offer the one grain size and render type because the render tester pots are designed purely as a means of allowing our customers to see the colour of the render.

Why should I Test my Coloured Render Before Purchase?

It’s essential for customers to test their coloured render before they go ahead and purchase it in bulk.

This is because our coloured renders may appear different on the colour chart to how it looks when actually applied on different buildings. A number of factors can cause this, for example your property may be facing a certain direction which gets lower or higher levels of light, thereby affecting the colour that your render appears.

Pale coloured renders can also reflect the colours within their surroundings. If you live in a very green area, your coloured render may reflect this and appear different to the colour chart. Likewise if you live next to the sea, your render may pick up on its bluish tones. This is why we advocate purchasing a coloured render sample pot before making a decision!

It’s also necessary when you are testing your coloured render to make sure that after you’ve painted it on, you leave it for 24 hours to set before making your final decision about whether or not you like the colour. Render is similar to paint in that it may appear lighter or darker when it’s wet and dry. You need to ensure that you like the way that the coloured render looks when it’s dry, because this is going to be the finished result.

What Do I Do When I’ve Decided on my Coloured Render?

After you have made that all-important decision, let your installer know and he/she will purchase the correct amount of render for your property! Or, if you are applying the render yourself, give us a call and we can help you to work out the amount of render you will need, and we can also give our technical advice.

Buy your Coloured Render Sample Pots Now…

You can purchase a coloured render sample pot in any of our available shades. Order as many as you need online or by phone and we can get it delivered directly to you!

choosing the right house render

The Best Type of House Render?

With a world of possibilities to choose from when it comes to making your house look great on the outside, the decorative finish to go for can be an overwhelming decision.

Our range of house renders is growing, and with expansion comes the need for more information so that customers can make an informed choice about which house render is right for them!

Currently, our render range includes a set of thin coat and thick coat options. In the thin coat category, we currently offer Acrylic, Silicone, Silicone Silicate and Mineral, with (spoiler) more exciting options on the horizon set to hit the shelves in the coming months. As for our thick coat renders, we offer Monocouche and our Heritage Lime Render.

But why would you want to use a thin coat house render as opposed to just a plain old sand and cement render? What are the benefits of different types of house renders, and where can I buy house render?

We have all the answers to all of your questions, so keep reading for more info!

What Does a Thin Coat House Render do?

Thin coat house renders are as the name suggests. They are applied in an extremely thin layer over the top of a specially engineered basecoat, which is designed to work in conjunction with the render to optimise breathability and flexibility.

Thin coat renders, similar to house paint, are available in hundreds of different colours and a range of different textures (for a smooth or rough finish). When we talk about what kind of properties a specific thin coat house render can offer a customer, we are essentially referring to the formulation of the render and its resulting capabilities. Some of these capabilities include vapour permeability, breathability, self cleaning and mechanical resistance (strength).

Thin Coat House Renders and Flexibility

The universal property that a thin coat house render will offer, however, is flexibility. You may have seen a property with cracks in the external walls, and this is caused by a combination of factors including weathering and poor installation of the render, but most likely it’s because the render is not flexible enough to cope with the movements of the house.

The external walls of your home will expand and shrink during cold temperatures and hot temperatures. This is only a tiny amount, but if your house render isn’t flexible enough you can definitely expect to see cracking over time. This is particularly distressing when you’ve paid for a job to be done, and its lifetime is considerably shorter than you were originally expecting. 

When you use a thin coat render, you are guaranteeing flexibility purely because it isn’t applied in a solid, thick layer. The basecoat underneath the render also has fibreglass mesh embedded within it. Fibreglass mesh is really flexible and has high tensile strength, so as your house expands it will hold the basecoat together and prevent cracking of your thin coat render.

House Rendering | Silicone Render

Currently, our top of the range thin coat house render is our Silicone render. Silicone render offers unsurpassed breathability and vapour permeability (it will allow water vapour to escape through it, thereby preventing damp). The inverse of this is that it’s also hydrophobic, so there’s no chance of water getting in. Silicone render is also self-cleaning, so it’s definitely the house render to choose if your house is situated in an area where there are lots of trees and plant life.

House Rendering | Silicone Silicate Render

Silicone Silicate is very similar to silicone in that it offers excellent breathability and vapour permeability. The only real difference between the two is that Silicone Silicate will only offer a limited amount of resistance to organic growth. It’s therefore better suited to properties that do not require a high level of self cleaning capabilities.

House Rendering | Acrylic Render

Our Acrylic coloured render is our most impact resistant. This means that it is extremely strong and therefore great for if you have kids who are keen on kicking footballs against your wall. When rendering your house with Acrylic render it does mean that because of its strength you sacrifice the breathability aspect that silicone offers, so it’s really a balance between which is more important for your circumstances!

House Rendering | 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, however 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.

Why Choosing the Right House Render is Essential

We always want our customers to make the right decisions and be happy with their finished product, which is why we aim to use these blogs as an informative tool. Choosing the right render is important to ensure a long lasting finish that will look fresh and nice for the duration of its lifespan!

Approved Installers of Thin Coat House Render

Here at EWI Store, we have a database of installers who have passed our training sessions and have subsequently become approved installers. What this means is that once they are trained in the correct use of our materials and have proven themselves to provide the highest quality of work, we recommend them to our customers.

If you are interested in finding a local approved installer, simply fill out the contact form below and we will be in touch!

 

Approved Installers Request Form

Your Name (required)

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Your Message

 

The Best Type of Insulation for EWI?

Since the recent addition of Wood Fibre Insulation to our systems, we’ve been talking to customers a lot about the benefits of different insulation materials and how they compare against each other.

Here at EWI Store, we have a broad range of insulation materials for use as part of our external wall insulation systems, so we wanted to give a more comprehensive comparison between the different types of insulation so that our customers can get the full picture! So without further ado, here is how Wood Fibre, Mineral Wool and EPS compare against one another…

Wood Fibre Insulation

Wood Fibre Insulation is our most environmentally friendly type of insulation. It is extremely appealing to the environmentally conscious customer, nonetheless its high performance is also a main attraction for customers.

Wood Fibre is also an extremely sustainable and renewable material. We source our Wood Fibre Insulation boards from a company called Pavatex, who are certified by the renowned natureplus standard – the European quality standard for building materials set up by the WWF, FSC and Greenpeace.

All of the timber used for their Diffutherm Wood Fibre Insulation boards comes from waste timber cuttings and their entire manufacture process aims to be as eco friendly as possible.

The Fire Resistance of Wood Fibre Insulation is rated at Class E, which is very similar to other insulating materials. However, Pavatex state that their Diffutherm Wood Fibre Insulation goes above other insulating materials because of the fact that it slows down the spread of fire. This is because the Wood Fibre is timber, which chars instead of burning. The charred exterior of the board creates a barrier which stops oxygen passing through and feeding the flames, thereby slowing the spread of fire.

Wood Fibre also offers something called a decrement delay, which is how long it takes for the energy of the sun to pass through. Many people think that all insulation keeps you cool in the summer, which is a myth. However, Wood Fibre does and this decrement delay depends on the thickness of the board.

Wood Fibre Overview:

  • Wood Fibre has a thermal conductivity of: 0.043 [W/(mK)]
  • 100mm of Wood Fibre can bring the U value of a wall down to 0.36 [W/(mK)].
  • Vapour diffusion resistance factor (μ): 5.
  • Price per square metre of 100mm Diffutherm Wood Fibre Insulation is £30.93 excluding VAT.
  • Reaction to Fire: Class E (see above for more info).
  • Recyclable and compostable.

Mineral Wool Insulation

We source our Mineral Wool Insulation boards from Rockwool, who offer the most non combustible insulation material on the market.

Rockwool insulation offers high levels of breathability due to the fact that it is a vapour open material. The presence of fibres and water-repelling compounds wick moisture and water vapour through the material away from the substrate, allowing it to escape. Mineral Wool is non-hygroscopic, which basically means that it pushes water away. It is a fantastic acoustic and thermal insulator because of the fact that the material is so hard wearing and the fibres allow for pockets where air becomes trapped and thus acts as an insulator.

Much like Wood Fibre Insulation, Rockwool is also made from a renewable, naturally occuring resource – volcanic rock. The insulation boards themselves are also 97% recyclable, which is slightly less than Wood Fibre’s status as 100% recyclable and compostable, yet is nevertheless still impressive!

Because of the fact that Mineral Wool is made from rock there are a number of associated benefits (resistance to rot and mould, long life span, hard wearing and water repellency) which makes it an attractive choice for customers. 

Rockwool Overview:

  • Rockwool has a Thermal Conductivity of: 0.036 [W/(m2K)].
  • 100mm of Rockwool insulation can bring the U value of a wall down to 0.34 [W/(m2K)].
  • Vapour Resistivity = 5.9 MNs/gm.
  • Price per square metre of 100mm of Rockwool Mineral Wool is £22.37 excluding VAT.
  • Highest Euroclass Fire Rating of A1.
  • 97% Recyclable.

EPS Insulation

Our final insulation material is Expanded Polystyrene (EPS). It’s the most affordable insulation material that you can get for external wall insulation, not only because the actual material is affordable but also because it is so lightweight it only requires lower strength adhesives and plastic fixings – which in turn cost less. The downside to EPS when you compare it to Wood Fibre and Rockwool is that it’s not an especially environmentally friendly material due to the fact that it is a type of plastic.

EPS is made from a polymer permeated with a foaming agent which, when exposed to steam, creates a uniform closed cell structure, highly resistant to heat flow and moisture penetration. EPS is 98% air and only 2% EPS, which means it acts as a fantastic thermal insulator because of its high air content.

EPS insulation products won’t burn but will likely melt away under high levels of heat. Fire retardancy is achieved by adding a small quantity of a fire-retardant agent to the material, which has the effect of ensuring that the EPS insulation boards shrink away from the energy expelled by heat. They also self-extinguish when the heat source is taken away.

EPS Overview:

  • EPS has a Thermal Conductivity of: 0.032 [W/(m2K)].
  • Vapour Resistivity = 200 MNs/gm.
  • Water vapour diffusion resistance factor (μ): 30-70.
  • Reaction to Fire: Class E.
  • Price per square metre of 100mm of EPS is £9.90 excluding VAT.
  • Generally Non-Recyclable.

Choose the insulation that is right for you…

So there you have it! If you are considering having external wall insulation installed on your property, it’s always best to be well informed about the options available to you so that you can make the best choice – so we hope this was helpful! For further information give us a call or leave a comment down below.

Stay tuned to our blog, we upload a new post every Tuesday and Thursday all about technical advice and materials FAQ’s!

Coloured Render Cost Per Square Metre

Here at EWI Store  we offer a vast range of coloured renders to suit all tastes. We also offer a same-day coloured render mixing service, so you can match the colour to your existing render or simply find the shade that you love. Our coloured renders can also be matched to NCS colours as part of our colour matching service! Buying render with us means that you can get the colour and finish that is right for you.

Choosing a coloured render for your home is a big decision to make, which is why we offer colour charts and render tester pots. However, once you’ve made the all-important decision of which coloured render to choose, how much will it cost you?

How much Coloured Render will I need?

To work out exactly how much coloured render you will need, we first need to work out the approximate square meterage of your property.

So to work out the square meterage of your external walls, you simply just need to go outside and measure the length and height of the wall then multiply those two numbers together. This needs to be repeated for each wall you intend to render and then totalled together. This will give you the external wall area.

It’s always good practice to prime the substrate before doing any work. Assuming the substrate is standard masonry, we would recommend that you use our water based primer, which costs approximately 30p per square metre.

Let’s also assume you want to install a Silicone Silicate render system with our standard EPS Basecoat. First we need to calculate how much Silicone Silicate render costs per square metre. One bucket of Silicone Silicate render will cover between 9-10m2, which is roughly £4.90 per square metre.

Then we need to take into account the basecoat layer which goes on before the actual coloured render itself to smooth out the external wall and aid adhesion. Using our EPS Basecoat, one bag will cover 4-5m2. Therefore, it will cost £2.40 per m2. The Fibreglass Mesh to be embedded within the basecoat will cost approximately 70p per square metre.

Now we just need to factor in how much primer will be required. With our Silicone Silicate system, you’ll need to use our EWI-333 SiSi render primer which can be tinted to match the colour of the render itself for extra opacity and pigmentation. Generally, we recommend that a large 21kg bucket of render primer will cover approximately 60m2. This means that the primer will come to roughly 80p per square metre.

Finally, we usually find that beading costs around £2 per square metre, although this can vary depending upon the property. 

So totalled all together, the cost of a silicone silicate render system per square metre should be approximately £10.80. Bear in mind that this is an approximation, but if you were to multiply this number with the square meterage of your property then you would get an estimate on how much the materials will cost for installing coloured render on your home!

Which Coloured Render do I Choose?

We have so many coloured renders to choose from, all of which are BBA approved and are the highest quality coloured renders on the market. Our tester pots provide the opportunity for customers to test different colours of render and pick the right one. It’s always best to be able to see the coloured render in person so that you don’t end up unhappy with your decision when it’s applied in full scale on your property.

We offer thin coat and thick coat coloured renders. Our thin coat coloured renders are best sellers; we offer a choice of Silicone, Silicone Silicate, Acrylic and Mineral coloured renders.

  • Silicone render/Silicone Silicate render: Silicone Render is a premium, modern technology coloured render – which is available in hundreds of different colours. Silicone is a very popular choice because it offers hydrophobic properties, which means that it repels water, dirt and organic growth. Silicone render is also super easy to apply because it comes ready to use, so you just apply it straight out the box. (Read more about Silicone Render here).
  • Acrylic render: Acrylic render is very similar to silicone, except for it doesn’t provide the same hydrophobic properties. It’s a solid middle-ground thin coat render because it still provides the same flexibility as other thin coat renders and it’s also great at holding onto colour pigment. (Read more about Acrylic Render here).
  • Mineral render: Mineral render is a dry-mix, thin coat render. This is a very popular choice if you live in a cold or rainy climate because mineral render is extremely fast drying (you can’t apply other renders in cold/rainy temperatures because they take longer to dry). The only thing about this render is that you need to paint it afterwards with silicone paint to seal it in. This is because if it’s left exposed to the elements it can develop lime bloom due to the presence of Portland cement. (read more about Mineral Render here).
  • Monocouche scratch render: Monocouche scratch render is a thick coat, through coloured render. It is more traditional, but does require extra work to install it. This is because the Monocouche needs to be applied in two passes for extra strength and cannot be applied in wet or humid conditions. Monocouche render then needs fibreglass mesh embedded within it to provide extra strength and flexibility (which means it will resist cracking), and then once it’s dried it needs scratching back to achieve the desired texture.

Buying EWI Pro Coloured Renders

When you order your render, we offer next day delivery and a specialist technical advice service. We believe in the importance of being able to offer our customers the benefit of our knowledge and so all of our sales team are well experienced in the use of our products and will be able to give the best advice on how they are best applied and how much you will need.

Stay tuned for more content! We upload a new blog post every Tuesday and Thursday all about our coloured renders and our External Wall Insulation Systems. Also follow us on Facebook, Instagram and Twitter for exclusive updates!