8.5 million external wall insulation in the UK have solid walls, and many of these are hard to insulate using the usual methods (such as cavity wall insulation). One solution is external wall insulation. This involves fitting an insulating layer to the outside of a building, usually finished with a render coat. There are a variety of options for the insulating material, including rock mineral wool, and the choice of finish is important in terms of thermal performance, reaction to fire classification, as well as cost and aesthetics.

It is worth bearing in mind that external wall insulation will change the appearance of a house, and this may be an issue for some homeowners. It’s worth checking with your local council if you live in a conservation area or on a Listed property, and they will advise you whether you require planning permission before committing to an EWI project.

EWI can improve a building’s thermal performance, resulting in reduced energy consumption and lowering household bills. It can also provide weatherproofing and help to regulate indoor temperatures, making a home more comfortable year-round.

The Ultimate Guide to External Wall Insulation: Benefits, Installation, and Cost Analysis

In addition to the benefits of reducing heating costs, breathable external wall insulation can help prevent condensation problems in buildings. This is because the insulating layer allows moisture vapour to pass through, and this helps reduce the risk of dampness and mould. Non-breathable insulation boards (such as polystyrene or foam) can trap moisture and lead to damage. Choosing a breathable option will avoid this, ensuring that your insulated walls remain permeable.