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Over 8 million homes here in the UK feature solid walls. This means there is either no cavity within the wall, or only a very slim one which is unsuitable for cavity wall insulation. These constructions are a source of heat loss, making it expensive to heat a home. Fortunately, in many cases it is possible to improve their performance by installing solid wall insulation. Insulation can either be fitted on the outer face of the existing wall (external wall insulation - EWI) or on the inner face (internal wall insulation - IWI). In both cases, if you live in England, part of the cost of this work can be covered with a Green Homes Grant.
In this blog, we look at the advantages of these different approaches, and how to decide which might be right for your home.
How can I tell if my property has solid walls?
Solid walls are most common on homes built before the 1920s. In most cases, brick-built solid walls will be roughly the length of a brick plus a few extra centimetres for plaster (usually around 230 mm in total). An easy way to measure this is by standing in an external doorway.
Another common sign of a brick built solid wall is if alternate bricks have been fitted with their short edge facing outwards. These bricks will typically run across the full width of the wall meaning no cavity is present.
If you are unsure about what type of construction your home uses, contact a suitable TrustMark certified installer, who should be able to quickly identify your home’s construction.
If you live in a house that has a non-traditional construction such as a concrete, steel or timber-framed building, you will need a specialist retrofit professional to advise you on your options.
Why is it a good idea to insulate solid walls?
Having a well-insulated and less draughty home can make a real difference both to annual bills and your health. The most recent English Housing Survey showed that most properties built before 1920 (typically solid walled) fell in the worst bands for Energy Efficiency (F or G). This meant that their average energy bills were more than double the cost of homes built after 2002 (£1259 compared with £603). This can be a serious issue, preventing some owners from being able to afford to heat their home. Properties in these bands were also shown to be more likely to suffer from issues such as damp which can allow mould to grow, putting your health at risk.
In many cases, owners of solid walled homes may have already fitted certain improvements to reduce heat loss, such as loft insulation and double glazing. However, with the external walls making up a good deal of the outer surface area of a home, it is important to consider how insulation may also benefit the property.
How much could I save by fitting solid wall insulation?
The Energy Savings Trust estimates that annual savings from fitting solid wall insulation range from around £105 for a flat to £375 for a detached home, but it also depends on the efficiency and fuel cost of your heating system and savings can be more.
In addition, a recent Government study has suggested that fitting solid wall insulation in your home may also help to increase its value.
Homeowners in England can apply for grants of up to £5,000 (£10,000 for those on lower income) towards the cost of fitting the insulation through the Green Homes Grant. You can find more information about the scheme in our Green Homes Grant FAQ.
A range of premium and high performance external wall insulation products.
Premium performance internal wall insulation products; insulated plasterboard for mechanically fixed and adhesively bonded insulated dry-lining.
Find out more about retrofit measures for buildings on our Retrofit Hub, which includes how to guides, videos and other helpful information.