Do I already have cavity wall insulation?
If you have a new house built within the last 10 years there’s a good chance it will already have cavity wall insulation. This will have been installed into the cavity as blocks of insulation when the walls were built. You would need to check what documentation you had when you bought the house such as a survey or check with the original builder.
Cavity wall insulation may also have been installed if the house is older. Once again you should have been given a certificate or some documentation when you bought the house.