Most homes built after the 1920s feature brick or masonry-based exterior walls with a gap between each ‘leaf’, which is known as a cavity wall. This gap is designed to prevent damp from penetrating a home, and can be filled with insulating material to keep heat in and reduce energy bills. The vast majority of homes with cavity walls can be insulated without disrupting their original appearance.
It is important to choose a reliable and competent contractor cavity wall installers to carry out the work, and make sure they are registered with the Kiwa Cavity Wall Installer Assessment & Surveillance Scheme or National Insulation Association. They should also have a valid VAT number. It is also important to check whether they have insurance cover in case something goes wrong during the process of insulating your home.
The most common method of installing insulation in cavity walls involves using rock wool or polystyrene boards to fill the gap between the two brick skins. This is called either full or partial cavity wall insulation (CWI). In older houses, it may be possible to use mineral wool to swell up the gaps between the bricks, but this is not as effective as the modern methods.
When insulating your cavity walls, it is vital that the installers are experienced and qualified, and have access to specialist equipment. In addition to this, it is important that the cavity wall insulation is installed correctly and that a vertical damp proof course is also installed around any openings such as doors or windows.
In order to install the insulation, the contractor will need to drill holes into your external walls. These holes are then injected with the insulation material through specialist equipment. Polystyrene beads are now commonly used, as they offer greater efficiencies than alternatives such as mineral wool and expanding foam. They are also easy to install, and don’t require drilling holes so wide that they damage the structure of the wall.
Once the insulation has been pumped in, it is essential that the gaps between the bricks are then filled with mortar to match the brickwork. This will help to prevent air pockets in the cavity, and ensure that the insulating materials are not blown away.
You should be able to feel the benefits of your insulation installation within a day, and should notice a reduction in your energy bills. Cavity wall insulation is a cheap way to reduce your carbon footprint, and the government recognises this by offering grants to assist with the cost of installing it. You can find out if you are eligible for this by contacting the Energy Saving Trust. They will be able to survey your property and advise on the best option for you.