To work out if your home has cavity walls is simple, Just take a look at the brick pattern. If your bricks run lenghtways across, then you have cavity walls. If your bricks run full lenght – half brick – full lenght etc, then you have solid walls. Solid walls cannot be insulated internally.
Is my cavity wall already Insulated?
If you have cavity walls, we now need to see if the gap betwen the bricks has been insulated before. Take a look at the photos and compare to your own walls.
The Punchholes are usually a couple of bricks below the windows and also spread out over the width of the entire wall.
Check to see if you have any “Punch holes” visible. They are usually in the mortar.
Please look closely, as the punch hole mortar fades in time and can be quite hard to see.
If you can see any of these, then your walls have been insulated.