Spray foam insulation is an alternative to traditional building insulation, and it can be used to insulate roofs, lofts, walls and floors.
It is a liquid foam that is sprayed into position within the insulating layer. The foam works as an effective insulator and can also stop water leakage.
Spray foam insulation does tend to cost more than other types of insulation such as mineral/glass-wool, polystyrene slabs or expanded polystyrene.
Types of spray foam insulation
There are two types of spray foam insulation; closed cell spray foam and open cell spray foam. Both types are made from polyurethane and filled with bubbles of gas or air.
Closed cell spray foam sets into a rigid solid, which can be used to help support the structure of your property if it’s in a bad condition. This type of foam tends to be a better insulator than open cell spray foam. This is because it contains lots of separate pockets of gas which slow down the movement of heat through it. It also works as a barrier to moisture, so you will need to make sure your rooms or loft is well ventilated to stop condensation building up.
Once set, open cell spray foam is less dense compared to closed cell spray foam – you can compress it with your hand. Because of this, it can’t be used as a structural support. It is also not deemed to be as good of an insulator as the closed cell spray foam. To overcome this, it means you will need to install a thicker layer to get the same level of insulation.
Open cell spray foam is often used as a sound insulator, as it blocks and reduces airflow. It also allows moisture through it, so there less worry of condensation building up in your house.
Cost of spray foam insulation
How much spray foam insulation costs depends on the thickness, the type, the size of the area you want to insulate, and how it’s installed.
The National Insulation Association suggests a guide price of around £20 to £50 per square metre. The lower cost is the price of a thin layer of the spray foam for stabilisation. The higher cost represents the price of a thicker insulating layer.