Wall insulation

Homes built before 1920 almost always had solid walls, but cavity walls have been common since the 1930s. Sometimes it’s easy to see from the pattern of blocks or bricks whether you have solid walls or cavity walls, but many homes in Scotland have a waterproofing render coating, or harl, so you can’t tell.

If your house has a harl or render coat that needs replacing, you may be able to improve the insulation of the walls at the same time. Cavity walls can be easier to insulate than solid walls, but some buildings aren’t suitable for cavity insulation.

• Cavity insulation You may be able to have cavity insulation injected and make big savings on energy — but it may not work if your home is in an exposed area with driving rain. Also, cavity insulation isn’t right for certain building systems, including timber frames and steel frames. Your best bet may be external insulation, especially if you’re replacing the render.
   

• External insulation If you have a detached house with solid walls, you can add a layer of external insulation under the render or harling (but check with the council if your home is in a conservation area). If you live in a flat, a semi, or a terraced house, you would need to agree with your neighbours for the whole building to have external insulation.
   

• Internal insulation If external insulation or cavity insulation isn’t practical, you could add insulated linings inside the rooms — but you will decrease the size of the rooms by at least a couple of inches and interrupt ceiling covings.

Get advice (and a 25 year guarantee) from a CIGA member (Cavity Insulation Guarantee Agency):

www.ciga.co.uk