Monthly Archives: April 2018

Coloured Render vs. Insulated Render – Ultimate Guide

In this industry, the terms ‘coloured render’ and ‘insulated render’ are bounded about a lot. The terms are often used interchangeably, however subtle differences do exist and in this blog we are going to take a look at these in a bit more detail.

What is coloured render?

Coloured render refers to render that is coloured right through it’s final decorative coat in one uniform appearance. Sand and cement render is not coloured render. When we refer to coloured render we usually refer to the EWI-010 Acrylic Render and the EWI-075 Silicone Render (also known as thin-coat renders), which form the final finish as part of a multi-layer build-up; or we refer to EWI-090 Monocouche Scratch Render, which is also coloured through and can be applied either on its own or on top of a basecoat preparation layer.

What are the differences in the coloured render types?

The acrylic or silicone renders usually come in wet bucket form and are manufactured in a standard white colour. To produce the coloured render, the acrylic or silicone renders go through a tinting machine, which consists of a pigment dispenser and a shaker. The coloured pigment is dispensed into a bucket in a controlled environment and this bucket is shaken-up by the shaker to produce one uniform colour throughout.

Monocouche scratch renders, come in a dry format, usually in 25kg bags – these are pre-mixed in different colours, and need to be mixed with clean potable water to make it ready for application.

Since monocouche render is pre-mixed with different colours, you will probably not be surprised to learn that the numbers of colours available with this type of render is limited. In fact, when going with a monocouche coloured render, you can pick from 18 different colours, but if you opt for the thin coat coloured renders you can literally pick from thousands of colours.

Another difference between monocouche and thin coat renders is the type of finish that is achieved. While the thin coat renders, usually leave a textured, sand type finish, the monocouche scratch renders achieve a pitted effect, by effectively leaving little scratches on the surface (hence often referred to as scratch coloured render). Both finishes look great, so choosing which coloured render to go for normally comes down to which look the end-user prefers.

The other differences between the two different coloured renders is how they are applied to the wall. The scratch render is in applied at a thickness of 18mm and scratched back using a scratch render scraper to give a final thickness of 16mm. Conversely the thin coat renders are applied at a thickness of 1-3mm onto a flexible basecoat layer (basecoat + embedded mesh). This means that a bucket of thin coat render will go far further in terms of coverage than a bag of monocouche scratch coloured render when applied to the wall.

Our dash receiver is also bagged like the monocouche scratch render and comes in different colours, but the decorative pebbles that stick on the outer surface form the main part of the decorative feature so the amount of actual dash receiver you can see is limited.

What is insulated render?

Very often when we refer to insulated render, we refer to a coloured through render backed on an external wall insulation material. This external wall insulation material can either be lightweight EPS, stone wool (mineral wool) or wood fibre insulation. The insulated render part is the final decorative layer that sits on top of the reinforcement layer, which in turn sits on top of the insulating material.  The whole system in therefore an example of an insulated render system or a external wall insulation system (EWI).

What are the differences in the insulated render types?

There are differences in insulated render types, which are characterised by the differences in the build-up – starting from the insulation material, to the reinforcement layer and then a variation in the decorative look.

For example, insulated renders can use one of the following insulating materials: EPS, Mineral Wool and Wood fibre insulation. Phenolic insulated can also be used in insulated render, but we don’t recommend this since it delaminates over time when in situ and also can react with metal fixings to create an acid that can leech on to the render.

Basecoats and reinforcement mesh may vary to achieve a different preparatory coat ready to receive the final coat. Basecoats can either be in the grey or white adhesive types. Also, the system build-up may contain a slight variation in the weight of the fibreglass mesh, with one coat mesh or two coat mesh being used for different impact resistance requirements.

Coloured renders like the thin coat silicone or acrylic can sit on top of an insulated render system and work very well. Monocouche scratch render can also sit on top of the reinforcement layer, but it is not commonly specified due to the weight/ load of this final coat of the coloured through render.

Can the render itself be insulated?

In certain and rare circumstances, the coloured render itself can contain special insulating properties, which when used as part of the render build-up can be considered an insulating render. These coloured renders don’t necessarily have an insulating material behind it. An example of a coloured render that is also an insulated render, is using a basecoat that contains a certain amount of the following ingredients (not limited to this list): perlite, EPS, cork or aerogel, and the product itself has a declared lambda value (ƛ) on the product packaging.

An example build-up of coloured render with insulating properties: the EWI-520 Insulating Basecoat with a layer of fibreglass mesh to give the layer flexibility; finished off with 1.5mm of the EWI-075 Silicone Render.

Although the insulated coloured render in this example has insulation properties, it would not replace the degree of insulation associated by installing a full external wall insulation system. You could install this type of system in areas of difficult access or where it would be tricky to thicken the walls by a certain degree due to width (boundary) restrictions around the property.

Coloured renders and insulated renders in summary

As discussed above coloured renders and insulated renders are used interchangeably in the industry but you do have subtle differences. Coloured render refers to the cement-based plaster applied either as a basecoat and a thin-coat decorative finish; or to a one-coat Monocouche Scratch Render applied in one pass onto the substrate.

Insulated Render usually applies to an external wall insulation system that not only contains a coloured render, but an insulation material that is adhered to the substrate. This insulation material can EPS, Mineral Wool or Wood fibre insulation.

Coloured render can also have insulating properties, but it must be declared on the packaging. However this can be used to take the edge of a substrate rather than as a prime insulating material for the purposes of thermal insulation.

What is Silicone Render? EWI Pro Coloured Renders

This week we are taking a look at our top of the line, through-coloured, silicone render in order to offer a little bit more technical info about why you would want to choose coloured silicone render, and what it can do for you and your home!

To start with, and to state the obvious, silicone render contains silicone. If you’re not aware of exactly what silicone is, it’s basically a polymer which is rubbery and heat resistant – it has a molecular structure built up by a large number of similar molecules which are bonded together. Silicone is typically used in adhesives, lubricants, medicine, make up, cooking utensils and thermal and electrical insulation. A great thing about Silicone is that it has a low thermal conductivity – so it’s perfect when used as part of an external wall insulation system!

Silicone rubber is widely used in the construction industry because it is known for its tensile strength, reliability and longevity. That’s why silicone is great for use in renders, because it provides an incredible level of flexibility which will help to prevent cracking in the long run.

Not only is silicone flexible but it also offers a high level of water resistance, but importantly at the same time it is vapour permeable. What this means is that your render won’t absorb any water, but it will allow water vapour from the inside to escape through it (water vapour moves from warm areas e.g. inside to cool areas e.g. outside). This will contribute towards the prevention of damp within your home by letting the moisture escape rather than building up within your insulation system and your walls. Moisture and condensation can hugely affect the thermal performance of insulating materials, so it’s a pretty important factor to consider.  

Because of its breathability, we recommend that silicone render is great for use in mineral wool systems – Rockwool insulation boards offers unsurpassed levels of breathability, so if you live in a humid, damp area then this is the perfect system!

We have found that silicone render works really well if you’re installing it in a place where algae and moss or organic growth are likely to occur, such as near water or plant life. This is because it is highly resistant to organic growth. What this means is that in the long run you are much less likely to have to clean your render, and even less likely to have to re-render before the end of its lifespan.

How to apply Coloured Render

Silicone render comes as a ready-to-use mix so you don’t need to add anything to it before use. It is advisable that you give it a bit of a stir first to ensure that all the colour pigments are evenly distributed throughout (if you’ve gone for a coloured render).

To apply the silicone render, you need to first install the basecoat mesh layer (EPS Basecoat Adhesive and fibreglass mesh embedded within it). This will create a smooth, even surface for you to render onto – you wouldn’t be able to apply the thin coat coloured render directly to the substrate because it is such a thin texture that you would be able to see brickwork etc underneath.

Once the basecoat layer has dried, you can use a stainless steel trowel to apply the coloured render to the substrate. To create an even, textured finish you will then need to rub up the surface of the of the render using circular motions with a plastic render float.

You will need to ensure that you have enough people on site to be able to apply the render to an entire wall at once. If you attempt to apply the coloured render section by section, then you will find that when it dries there will be a scarring effect where the different render sections meet.

To apply silicone render, you will also need the right weather conditions. Rain, wind or too hot/cold temperatures can have a negative impact upon the finished result. Make sure that it is not due to rain during installation and drying time.

Silicone Render vs Silicone Silicate Render

Silicone render and silicone silicate render are the twin siblings of the EWI Store render group. Both renders are well matched in terms of performance, the only real difference between them is that silicone silicate contains sand granules which makes it slightly less resistant to organic growth.

Silicone silicate is one of our most popular renders. It’s also the slightly cheaper than silicone render because of the addition of sand, which is a less expensive material. However, for the performance of the render you aren’t losing out by paying less.   

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

U-values and Insulated Render Systems

Our insulated render systems are a great way to help improve the thermal comfort of your property. They are also a great way to reduce energy bills – less heat escaping through the walls means your boiler needs to work less hard. 90mm of our graphite enhanced expanded polystyrene (or EPS as it is more commonly known) can halve the heating part of your energy bill. Couple this with the fact that many older solid wall properties are also damp, wrapping your home in a watertight insulated render system can significantly improve the internal environment – providing a drier more comfortable dwelling.

Part L of Building Regulations stipulated though that certain targets have to be met when improving existing building fabrics (like walls) or when you are building a new property from scratch. The target for insulation is known as the u-value, and basically this shows heat loss for a given wall.

Insulated Render and U-Value Regulations

In the domestic sector, there are 3 targets that people need to be aware of

  1. Installing insulated render systems on existing properties;
  2. Installing insulated render systems on extensions on existing properties;
  3. Installing insulated render systems on new builds.

If you are adding insulation to existing properties (i.e. Target 1 and Target 2), you are only required to hit the targets if you are installing the insulated render system on more than 25% of the entire surface of the property.

This means that if you are trying to improve just a small part of the house such as the walls of an exposed cold bedroom, then potentially (provided this is less than 25% of the total wall area) you can add as little insulation as you want.

Now, without going too much into the maths behind the u-value target – every building fabric has an existing u-value, or a level of heat loss. If you add insulation to the building fabric, then there is less heat loss, so the u-value goes down. The targets set by the Building control can be used on every type of wall, it just basically means that the starting u-value will be different, and therefore the amount of insulation that is required to hit the target will vary.

To keep things simple, we are going to be concentrating on solid brick walls – which is a very typical building construction in the UK, and since they can’t be insulated with cavity wall insulation – a common building type that gets fitted with our insulated render systems.

An existing 225mm solid wall has a starting u-value of 2.16 W/m2k.

  • When installing render systems on existing properties, the target u-value that needs to be reached is 0.30 W/m2
  • When installing render systems on extensions on existing properties, the target u-value that needs to be reached is 0.28 W/m2
  • When installing render systems on new builds, the target u-value that needs to be reached is 0.18 W/m2

Insulated Render and Insulation Thickness

So what kind of thickness of insulation will achieve this? Well it varies whether you are using mineral wool or EPS.

  • To hit a u-value of 0.30, you require 90mm of EPS or 110mm of mineral wool
  • To hit a u-value of 0.28, you require 100mm of EPS or 120mm of mineral wool
  • To hit a u-value of 0.18, you require 190mm of EPS or 210mm of mineral wool

Obviously, it is worth pointing out that there is nothing stopping you beating the targets! If you want to add 300mm of insulation to your extension and take the u-value down to 0.12W/m2k, then there is nothing stopping you do it! At EWI Store, we can source EPS at any thickness between 20mm and 400mm!

So there you have it, the targets that need to be hit, and also the insulation thickness that is required to hit them.

job vacancy, sales vacancies

EWI store is hiring!

Based in the building and construction sector, we are the leading seller of external wall insulation systems in the South East. We have a large database of installers across the UK who use our systems and materials. We’re excited to say we’re looking for a full-time sales executive to join us in our Chessington branch and help us as we continue to grow our brand!

The role is a great opportunity to take a first step into business development, with generous commission and growth opportunities as the business expands. We are keen to maintain strong a relationship with our customers, so excellent customer service and organisation skills are necessary. The role will contain an element of marketing and will provide excellent experience and opportunities to gain new skills and training.

Job description

Sales-driven, promoting the company’s distributed range of products.

Office-based with the potential to support field based sales

Selling to a mix of homeowners and small-to-medium specialist installers

Working with a field salesperson to following up leads and enquiries

Monitoring online lead generation tools and following up leads

Salary: £23,000 

Performance-based bonuses available

Required skills and attributes

Organisation 

Ability to multi-task

Happy being new business-focused

Team player

Able to build strong relationships

Verbal communication – making phone calls

Good access to the office

Ambitious and driven

 

Want to apply? Go to our Careers page by clicking here 

Are you a Render Installer? EWI Pro Approved renderers

Are you a renderer looking to get more leads? We are the leading expert in render-only and external wall insulation systems. We have a large network of installers throughout the country, and we are looking for more renderers to join our team of approved installers!

How do I become an approved renderer?

To become one of our approved installers, all you need to do is attend one of our specialist training days! They run every Thursday and offer a comprehensive course on each of our coloured renders and insulated renders, how they work and how they are best applied. You’ll also be shown how our coloured renders work in the context of our EWI systems.

Our trainers have years of experience in insulation and rendering, and will be sharing loads of tips and tricks to make sure you get a great finish every time. They will talk you through the properties and benefits of different insulating materials and coloured renders, and show you how to install them with our range of beading and fixings.

These sessions are a great chance to get hands-on, with all training materials provided free of charge – and you will use all the best tools and machines in our amazing training facilities.

If you are a renderer and you’re interested in attending one of our training days, then give us a call and book your place! We only ask for a small deposit to encourage attendance, which will be returned to you after you have completed the training day.

What are the benefits of becoming an approved renderer?

After completing the course, you will be added to our installers list where we will send you customer leads in your area for people who are interested in re-rendering their homes using our coloured renders and insulated renders.

As an approved installer, you can also join our installer loyalty scheme where we offer you points for each purchase that you make, which means you can go on to use your points to claim fantastic prizes!

Why use EWI Pro coloured renders?

EWI Pro renders are quality assured, BBA (British Board of Agrément) approved renders which are high-technology and modern. and we have a comprehensive range of thin coat and thick coat renders, all of which come in a wide range of colours (we have on site colour mixing equipment – so thousands of colours available!) and grain sizes for a customisable finish to suit your client’s tastes. 

EWI-075 Silicone Render

The premium render in the EWI Pro catalogue, offering unsurpassed performance. It is breathable, flexible, robust and long-lasting. It is a through colour render, available in hundreds of colours!

EWI-040 Silicone Silicate Render

Suitable for interior and exterior surfaces, but works best when applied on top of a reinforcement layer as part of the whole thin-coat render or insulation system. The silicone silicate coloured render not only provides a decorative finish (it is through coloured), it also provides a strong protective coating to the property, helping protect the underlying brickwork. Silicone silicate render is also breathable, so can be used in conjunction with mineral wool EWI systems.

EWI-010 Acrylic Render

The best value render in the EWI Pro catalogue. The render will form a long-lasting, aesthetically-pleasing protective barrier on your external walls. It is flexible, and highly resistant to mechanical impact. Acrylic render is a fantastic coloured render. It is particularly good at holding vibrant colours, and can be mixed into almost any shade.

EWI-060 Mineral Render

Dry-mix finish, for external wall insulation and render-only systems. The render is breathable and quick-drying, making it ideal for those looking to install in colder, more humid conditions. Mineral Render requires painting with EWI-005 Silicone Paint.

EWI-050 Mosaic Render

A ready to use decorative, coloured render. It is made up coloured quartz aggregate held within a transparent acrylic resin binder. The mosaic render is particularly durable, making it ideal for exposed surfaces prone to damage and soiling (for example the DPC area).

EWI-090 Monocouche Scratch Render

EWI Pro Monocouche Scratch Render is a polymer modified one-coat decorative dry mix render. It creates a low maintenance textured finish on external walls. We’ve heard excellent reviews on our Monocouche render from renderers who say it’s the best on the market!

If you’re interested in trying any of our coloured renders, we can send out samples and price lists for you to give them a go! We can guarantee you will love them.

Get in touch to become an approved renderer!

Here at EWI store, we are technical experts on our entire product range. This includes installation and technical advice. We receive calls daily, asking for our advice and we are always pleased to answer any of questions. Do give us a call or an email and we would be happy to help!

To become an approved renderer, you can book your place at our next training day by calling one of our sales representatives. We look forward to hearing from you!

Our silicone silicate #render in action! #rendering #thincoat #EWI

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External Wall Insulation and Verge Trims

Verge Trims are suitable for most situations requiring the capping of external wall insulation systems and rendering systems.

A verge trim is a thin strip of plastic or metal that sits at the top of the wall where the insulation meets the roofline. Our verge trims are made from 1mm powder coated aluminium. This verge trim is designed to be tucked up behind the fascia board and comes in various widths to house different thicknesses of insulation. The purpose of verge trims is to create a water-tight seal that prevents any moisture penetration behind the system.

As we know, water ingress can be extremely detrimental to an EWI system. Water has a direct effect on the insulating properties of the EWI because water reduces the ability of the insulation to slow heat transfer. Water ingress can also be really dangerous for the structural integrity of the external wall insulation system. Continuous water penetration will eventually wear away the adhesive materials, which can eventually cause the insulation boards to become insecure and even fall off the wall and cause injury. This is why technical design using verge trims is so important, and why EWI installations need to be done properly by fully trained installers – such as ours.

When it comes to an EWI installation, properties will vary depending upon the type of roofs they have. Some roofs have a wide enough soffit to allow the insulation to sit underneath. In this case, good quality beading will be sufficient to create a seal with the soffit board, and water ingress should never be a problem because the water will simply run off the side of the roof. However, not all roofs have a wide enough soffit to accommodate the insulation, and in these cases, a verge trim is usually required to ensure the water does not run down the back of the EWI boards.

Extending the Roofline with Verge Trims for EWI

Extending the roofline with verge trims is particularly useful on gable walls where the tiles stop abruptly at the edge of the gable wall. In this situation, timber battens can be installed, and a new row of tiles can be added to create an extended roofline on the property. The insulation will then slot underneath this perfectly, creating an ideal waterproof solution.

However, there is a downside to this method. The cost of this procedure is can be somewhat expensive, especially when considering that external wall insulation isn’t exactly a cheap procedure. so here at EWI Store we have taken this into account and we have designed a more affordable option which is equally as effective.

Verge Trim – Creating a Waterproof Seal for EWI

The solution is simple: where there is a fascia board, it is possible to tuck verge trim behind it, or up under the roofline. Here at EWI Store, we offer a range of verge trims to suit your needs. Our Verge trims come in two standard sizes 110mm and 140mm. We offer three types of Verge trims.

Verge trim type 1: This verge trim can be tucked up behind the facia board and then attached to the wall using screws at 300mm centres eliminating the need for silicone as there are no sites for water ingress

Verge trim type 2: This verge trim is the standard verge trim which is placed under the roofline. The join is then sealed with silicone sealant to help prevent water ingress. This is usually sufficient where there is guttering to help the water drain away, but in more exposed places the silicon can fail quickly and allow moisture behind the system.

Verge trim type 3: This verge trim is to be used in place of fascia board this provides a water tight system which prevents water ingress behind the EWI System.

We offer a selective range of different styles and colours of verge trims to create your dream property. Give us a call on 020 3397 4067 to get a quote for our EWI system or if you need an EWI installer.

using foam tape, tape adhesive with EWI, expanding foam sealant tape

Using Expanding Foam Tape in an EWI System

Having recently started stocking Expanding Foam Tape as a part of our EWI materials line-up, we’ve been speaking to a lot of installers and customers about the benefits of using Expanding Foam Tape as a sealant within an external wall insulation system.

If you are a regular reader, or you’re familiar with external wall insulation, then you will know that moisture and water vapour can be detrimental to the way that the EWI system performs. The presence of water can decrease the insulation system’s ability to insulate by a shocking 50%. As well as this, water can enter the system and freeze causing damage to the render and the insulation boards. Therefore, ensuring that your EWI system is totally sealed (especially at weak junctures) is really important.

So, in what instances can I use Expanding Foam Tape when installing EWI? We wanted to explain a couple of situations where Expanding Foam Tape can play a really useful and important role as part of an external wall insulation system.

Using Expanding Foam Tape for EWI and Window Joints

A good example of when you may need to use Expanding Foam Tape in an EWI system is around windows – particularly window sills. For example, if you are installing EPS onto a building then you are going to need to install the EPS so that it tucks right up underneath the window sills.

Areas where the EPS terminates against other building components (e.g. window sills) will need sealing with tape. As we know, buildings expand and contract during heating and cooling. Therefore, during this expansion/contraction, areas where the EPS is in direct contact with the window sill can form exposed cracks where the weather can penetrate, and moisture can build up.

Installing Expanding Foam Tape in an EWI system as a joint sealant is a very effective way of preventing moisture build-up, as the foam will accommodate the impact of the continual minute movements of the building by expanding and contracting with the building components, therefore providing a waterproof seal.

Using Expanding Foam Tape for EWI and Verge Trim

Verge trims are great for capping over the top of your insulation system where the roof line does not fully extend out enough to cover the EWI system and protect it from the elements. Verge trim is installed over the top of the insulation, redirecting water down the water-proofed side of the external wall insulation. When installing verge trims, you would need to apply the Expanding Foam Tape to the top edge of the insulation material (e.g. EPS) in order for it to expand and fill the gap in between where the insulation meets the underside of the verge trim.

The top edge of the insulation is a very vulnerable area in terms of being exposed to the elements. The verge trim therefore acts as a shield so that water will run off the side of the EPS, rather than seeping down the back. However, it’s important to ensure that no moisture can build up in between the two components as this would eventually cause damage and detriment to the system, so therefore sealing the area with Expanding Foam Tape is really important.

Top tips for installing Expanding Foam Tape in an EWI system

  • Ensure that the area of application is clean, dry and dust free so as to allow for optimal adhesion.
  • When installing in hard to reach places, use a spatula to press down on and secure the tape.
  • The joint will close as the foam expands, however in colder temperatures this will be significantly slower.
  • Never install around a corner – instead form a butt joint and overlap the tape at both ends.
  • When starting a new strip of tape mid-way along a joint, overlap the strips from end to end.
  • Always cut off extra tape (around 10mm per metre) to allow for any recovery of stretching that may have occurred during installation.
  • For best results, ensure that level changes of cracks/joints are as small as possible.
  • For joints of changing width, use tape of different widths and overlap the ends.