What’s a cavity wall?
A cavity wall is made up of two brick-thin walls. These walls are known as skins or “leaves”. A gap is also known as a cavity. They are held together by metal wall ties.
How to determine if your walls have cavities
The first indicator is your home’s age. To determine the age of your home, you can inspect any brickwork. If your home has cavity walls, bricks will be of equal size. If all brickwork has been covered up or rendered so that it is impossible to see the bricks, you can determine the thickness of the outer walls. You can also inspect Windows and Doorways. Cavity walls are brick walls with a thickness of more than 10 inches. Solid stone walls, however, can be very thick.
How do you find out if your home has cavity wall insulation
Your walls are likely to have been insulated if your home was built within the last 20 years. You can verify if they were or not.
- A professional installer should drill a small hole in the wall. This will tell you if the wall has insulation or not. This is known as a borescope inspection.
- To verify insulation, contact your local building control department.
- These clues can also help you avoid the borescope inspection.
- Installers will drill 1-inch holes at regular intervals when installing wall cavity insulation.
- Inspect your attic. You might see the cavity insulation material seeping from the top of your wall. This is a problem. It is best to call a professional to remove the item and seal it.
How can you insulate a home without brick walls?
Stone walls may be a feature of your house. These walls are solid and do not require insulation. Our ultimate guide to solid wall insulation might be of interest.
Cavity walls are not permitted in pre-fabricated concrete homes, timber- or steel-framed structures. These structures may be insulateable in another manner. For help finding a local installer, contact the National Insulation Association.
It is not a good idea to ask a contractor for wall cavity insulation between the outer brick leaf of your home and the timber frame. This can lead to severe damage.
Are cavity walls insulation the best choice for your home?
Cavity wall insulation should only be used if:
- Brick-brick cavity walls aren’t filled.
- The cavities should be at least 2 inches in diameter.
- Brickwork and masonry in excellent condition.
- Access to your exterior walls is possible. To join them to a neighboring home, the installer will need to install a cavity barrier. This could increase the cost. It is possible that installations around garages or conservatories are not permitted.
- Your home should not be more than 12 meters in height (or 4 stories).
- Dry walls are best. It is better not to have insulation than damp walls. Before installing insulation, you will need to determine the source of dampness. Cavity insulation won’t work if you have walls that are often exposed to driving rain.
- There are no single areas of steel or timber-framed construction.
Timber-framed homes often look exactly like bricks, even though they aren’t. These buildings cannot be cavity wall insulated as they need the cavity to allow for moisture escape. To verify this, you can inspect your attic. Timber-framed houses have party and gable walls made from timber instead of brick.
How do you install cavity wall insulation
Make sure your walls are in good condition. You must ensure that your walls are in good condition and free of dampness. After drilling small holes, they will use special equipment to blow insulation into the cavities and then add mortar.
A professional installer should be able to complete the job in two hours for a house of average size with accessible walls. It is important that you do not leave behind any mess.
They shouldn’t be allowed to enter your home for any type of work.
What type of cavity insulation will they install?
Cavity wall insulation can be made from mineral fibre wool, polystyrene (also called beads) granules. All of them must be made according to British standards.
Mineral wool
Mineral wool is most commonly used for its softness. It functions in the same manner as mineral “quilt” insulation, but it is cut into smaller tufts that can be blown into walls. It must be kept dry to retain its insulation properties. It can also settle over time, causing air pockets at the walls’ top.
Granules & beads
Beads and granules are popular options. They are efficient at creating wall insulation and trap heat well. But loose granules can escape through the airbricks and sometimes leak out of walls.
Foam
- Foam insulation is the best for thermal cavity walls. However, foam installation is not easy and should be done by professionals. Some foams may also become unstable over time.
- Untrained installers could block flues or airbricks.
- They may blow insulation materials off walls and into your loft, next-door, or the ceiling.
- If they do not evenly distribute the material, it could create air pockets. This could cause cold areas in your walls, which can lead to condensation and mould.
- Cavity insulation can lead to wall ties becoming rusty. This can only happen if damp is allowed to get into brickwork or walls that are falling apart from torrential rain or other factors. Avoid cavities wall insulation.
Other methods are also available to insulate your house.
There are helpful guides available that will assist you in improving the insulation of your home, including for the roof, loft, walls, as well as for windows, doors and windows.
Loft insulation
While we lose the majority of our body heat through our heads, 25% of heat escapes through uninsulated homes through the roof. Insulate your loft to retain heat and save money.
