How Do I Know If I Have Cavity Wall Insulation?

How do I know if I have cavity wall insulation?

Cavity walls exist in properties that do not have solid walls, and usually date after the 1920s. Without adequate insulation in these cavities, a home can be highly inefficient and add to your heating costs.

But what if you don’t know if you have cavity walls, or indeed if they have already been insulated? There are ways to carry out a cavity wall check, and if you need to, to arrange to have cavity wall insulation fitted at your property. Read on to find out more…

What are Cavity Walls?

Cavity Walls are made up of two distinct walls that are regarded as one yet have a gap or cavity between them. A hollow wall’s two walls are known as its leaves, with the outer wall known as the external leaf and the interior wall known as the internal leaf.

A property that is without cavity walls will be of solid wall construction, and therefore there is no cavity to fill, in which case solid wall insulation is the suitable option.

What is Cavity Wall Insulation?

Cavity wall insulation is when insulating material is installed in the space or cavity between the inner and outer walls of a home, and it is an effective technique for retaining heat in a home. As heat rises, it tries to escape the warm boundaries of an indoor environment and will quickly attempt to move outdoors into the colder air.

Cavity wall insulation includes spraying expanding foam into a cavity wall to create an additional barrier between your home and the colder conditions outside. Installing wall insulation increases heat retention inside a home by up to 35% over an uninsulated wall.

What exactly is cavity wall insulation?
Image: What is cavity wall insulation?

How Do I Know If My Property Has Cavity Wall Insulation?

There are several ways to identify whether your home has cavity walls and if you already have cavity wall insulation.

To begin, you might look at your property’s EPC (Energy Performance Certificate). The EPC should specify the type of walls of your home. It will usually state if they are cavity or solid in structure. If you can’t find your EPC at home, you can use your postcode to look it up on the Government’s EPC Register.

Visit and click the “Retrieve Report Using Property Address” button.

To download your EPC, enter your postcode and choose your house. The second page will show the wall type and insulation.

Your home is likely to have cavity walls if it was built after the 1920s. Solid walls are more common in older homes. If your house was built within the last ten years, it most likely had cavity wall insulation put in at the time.

Check the brickwork on the exterior of your house to see if you have a cavity wall or not. If your house has cavity walls, the bricks will typically be laid in a regular manner, with the bricks arranged lengthwise.

Cavity wall
Image: A cavity wall

Solid, single walls are typically less consistent and have a more uneven brick pattern, displaying both the square ends of bricks and bricks stacked lengthwise.

Uneven Wall Pattern
Image: Solid brick wall

If your brickwork has been covered by render you can usually identify the status of the brick wall by measuring the breadth of the wall. Examine a window or door on one of your external walls to accomplish this. If a brick wall is more than 3000mm thick (from the exterior to an inner wall), it most likely has a cavity; a narrower wall is most likely solid. Stone walls can be even thicker, but they are usually sturdy.

Many contractors should have installed unique air vents, as shown below, which can be a good indication that cavity wall insulation has been installed to a high grade of quality.

Bore holes in the masonry walls are another sign that you already have cavity wall insulation. As part of an energy or insulation survey, many insulation companies will conduct this test to determine whether insulation has been installed.

Get Cavity Wall Insulation Installed

If you discover that you have unfilled cavity walls or are they are inadequately insulated and you find that your home is chronically cold, regardless of how much money you spend on your heating, it is critical that you look at installing cavity wall insulation.

If your home is persistently cold even when the heating is turned on, this indicates that heat is escaping from your property, implying that your walls are insufficiently insulated, and you are essentially wasting money every time you switch on the heating.

Cavity wall insulation is not for the typical DIYer, and it is always recommended that you speak with an insulation specialist who can go over all of your wall insulation options and the cost of the labour needed. They should also be able to tell you how much money you may save on heating bills if you have sufficient cavity wall insulation installed in your home.

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