If your house was built in the last 20 years or so, the walls are probably already insulated. To find out whether they are, you can do the following:
- Ask a registered installer for a borescope inspection. The installer will drill a small hole in your external wall to see if your walls are hollow or filled.
- Check with your local authority’s building control department.
Your home will be suitable for standard cavity wall insulation if it meets the following criteria:
- Its external walls are unfilled cavity walls.
- Your cavity is at least 50mm wide, and is clear of rubble.
- The masonry or brickwork of your property is in good condition.
- The walls are not exposed to driving rain.
- Your house is not at risk of flooding.
You will need an installer to carry out a survey to check that your house is suitable. If so, they will then be able to insulate your walls using mineral wool or polystyrene beads.
If your house has narrow or uneven cavities, is in an exposed site or there is a risk of flooding, then it may be possible to fill the cavity with polyurethane foam. This is more expensive than standard cavity wall insulation but is a particularly effective insulator. You will need a specialist foam insulation installer to survey your home for this, and to carry out the work if suitable.
If you have any damp patches on your internal walls then they should not be insulated until the problem is resolved. Speak to a builder who specialises in damp prevention.
If your home’s external walls are joined to another house, the installer will need to insert a cavity barrier to contain the insulation so your neighbours aren’t affected.
If you live in a flat then you won’t be able to have just your flat insulated – you will usually need to get agreement from everyone to insulate the whole block.