Tag Archives: Insulated render

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. Our coloured renders can now be matched to NCS colours as part of our colour matching service!

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.

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.

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 to 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 insulation systems.

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 fill out our contact form below, or you can book your place at our next training day by calling one of our sales representatives. We look forward to hearing from you!

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