Worker with Ladder

External Wall Insulation (EWI)

1

Key Fact

Reduces heating bills by up to 45%.

2

Key Fact

Reduces carbon footprint by cutting Co2 emissions.

3

Key Fact

Improves the air-tightness of a building.

What is External Wall Insulation?
 

External wall insulation is also known as “solid wall insulation”, and sometimes just shortened to EWI. It is used to insulate houses that do not have cavity walls. These are usually older homes (pre-1920s), including many traditional terraced houses.

 

External wall insulation is attached to the outside walls of a house, covered in several protective layers, and finished off with either render or another decorative finish.

What are the benefits of External Wall Insulation?
 

 • Provides major aesthetic improvements to a building

 • Very flexible, it hides cracks in old plaster

 • Ensures consistent U-values

 • Improves the air-tightness of a building

 • No disruption to building interior

 • Does not reduce internal floor area

 • Can eliminate thermal bridging

 • Renews aging exterior finishes

 • Large range of renders and textures

 • Massive choice of colours

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The Technical Part...

One of the fasting growing markets in the rendering industry is EWI.

 

This involves attaching insulated blocks to the external walls of your property and then finishing with either a Monocouche (French for "1 layer"), through coloured render, or a thin coat acrylic render system.

 

It means that instead of having to insulate from the inside, a process that causes major disruption and also means you lose a lot of room space, we can work from the outside.

 

There’s no need to move out while the work is done (as is necessary when it’s done internally) and you get a fantastic choice of finishes. Also, there are no internal decorating costs to allow for, as the inside of the property is left completely untouched.

Additionally, you'll save up to 45% of lost heating costs, so, you can see why this market is booming in the UK right now. These modern rendering techniques have become a major part of what we do nowadays and we love doing them! There’s nothing better than transforming a property and it’s one of the most rewarding services we offer.

If you live in an older house, you've probably noticed that your heating bills increase in winter. You may also notice that even when the house is warm inside, some of the walls feel cold to the touch or have condensation. That’s because most pre-1920’s homes (which includes most terraced houses) have solid brick walls which are poor at keeping in the heat. The good news is this – solid walls can be treated with external wall insulation.

   

  

Do you need External Wall Insulation?

Cavity wall insulation is easier and cheaper to install than external wall insulation.

 

EWI is designed only for properties that either a) do not have cavity walls, or b) are ‘hard to treat’ e.g. the cavities are too small to insulate.

 

How does it work?

Similar to cavity wall insulation, EWI creates a barrier that stops heat escaping through your walls. Unlike loft and cavity insulation however, EWI uses a rigid insulation material – expanded polystyrene slabs. Expanded polystyrene contains thousands of trapped air pockets, which makes it an extremely good insulator. It is also easy to cut to into shape, meaning it can fit neatly around windows, door frames and other architectural features.

 

The slabs are held in place with fixing anchors which are drilled into the existing walls and then covered with a layer of reinforcing mortar. This is covered with a glass fibre mesh, which when dry gives the insulation system its structural strength.

Finally, a primer layer and a decorative render go on, making the house look as good as new (or dare we say it, better than new!) The insulation adds about 9cm to the thickness of your walls, so the shape of your house will not look drastically different.

 The process does take several days, depending on the weather. Luckily for you the work all takes place outside, so other than having to walk under the scaffolding when you go in and out of the house there is very little disruption.

colours exterior render
colours exterior render
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exterior wall
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thin coat krend
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thin coat krend
thin coat krend
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thin coat krend
thin coat krend
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