Houses in the UK that were built from 1920 onwards usually had external walls that have a small gap or cavity in between them. These are called “cavity walls”.
The air gap works in the in the same principle as the air gap in double glazing which made the homes more energy efficient than the old solid brick ones. However, we can further improve this by filling the gap on cavity walls with simulating foam.
How do you find out if your cavity walls are unfilled?
Chances are, they already are insulated if your house was built in the last ten years or so ago. Here are some ways you can find out:
- Ask for a boroscope inspection to be performed by a registered installer. To see if your walls are filled or hollow, they will drill a small hole on your outside wall.
- You can also check with your local authority’s building control department as they would have information if your cavity walls have already been filled.
How do you determine if cavity wall insulation is ideal for your home?
These are the main characteristics for a home suited for cavity wall insulation:
- Its outside walls are unfilled cavity walls.
- The width of your cavity is no less than 50mm.
- Brickwork is still intact or in good condition.
- The walls are not directly exposed to driving rain.
Benefits of Cavity Wall Insulation
The process of installing foam on the cavity walls is simple. A hole is drilled in the external wall and the foam is pumped into the cavity or the gap. It is a relatively fast process and the energy savings you will make on heating costs give a small payback time.
Heat normally flows from a warm area into a cold one. Especially during winter, the lower the temperature outside, the faster the heat from your home escapes to the surrounding air.
What cavity insulation does is that it slows down the rate at which the heat escapes by keeping as much heat as possible inside your home for as long as possible.
By filling up the gap between the walls with a material with a lot of material with smaller air pockets in it, such as foam, cavity wall insulation makes it much harder for heat to pass through your walls. These pockets are more efficient at decreasing heat transfer through convection than the larger air cavity was. It is virtually impossible for large convection currents to be set up because of this.
Heat transfer by convection is reduced by making the air pockets really small which in turn reduces the size of convection currents.
Heat transfer by conduction is kept to a minimum as that of cavity walls because the plastic foam is a good insulator-just the same as how dry air is.
However filling your home’s cavity walls is not an easy job that you can do yourself. It would be best to find a registered and professional installer. A professional can finish the job in no more than two hours granting you have readily accessible walls. It should be simple and quick without any mess.
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