External Wall Insulation

What is External Wall Insulation?

External wall insulation, EWI, is an additional layer added to the outside of a building to help with its thermal insulation, ultimately keeping the house warm in winter. Not only does the additional layer help maintain the temperature inside the building but in doing so also keeps costs down by needing less heat.

What are the advantages of External Wall Insulation?

External wall insulation tends to be applied on older buildings where the construction of the property used solid walls meaning that cavity wall insulation cannot be applied. This leaves the occupant with two options, insulate the inside of the property or the outside of the property. There are a number of reasons for choosing external insulation over and above internal insulation, one of which is because it tends to involve less work as pipework rarely needs to be moved. Another reason is to keep the internal dimensions at their maximum size, by insulating the inside of the property the size of the room because smaller whereas the insulation the exterior leaves the inside intact.

Are there any negatives with External Wall Insulation?

If applied correctly there should be no negatives to having external wall insulation applied to the outside of a building. Some assume that because external wall insulation is an additional layer and keeps in the warmth that there is a danger of mould building on the inside of the property, however the insulation is applied around the existing air bricks and vents so should still allow the building to breathe. To ensure good ventilation, breathable render could also be used.

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