Is my cavity insulated?
If your home has a cavity, there is a chance that it is fully or partially filled with an insulating material. But how can you know for certain? Read on and find out.
The cavities of exterior walls or houses dating from after World War II may have been insulated. The more recent the home, the higher the chance of cavity wall insulation. You can consult the documents and invoices related to your home to find out whether the cavity wall has been insulated. If you cannot find definitive information there, check the drill holes of any cavity wall insulation carried out previously to see if there are any colour differences.
If you cannot find them, try removing a ventilation grid or the pipe of the cooker hood to see the cavity wall insulation. Alternatively, place a folding rule in a weep hole or drill a hole in a spot where two joints meet. In some cases, you can now feel whether there is any insulation. If you pull back the folding rule and insulation material is sticking to it, the cavity wall is filled up.
If you don’t see anything, insulation may still be present as this method does not work well for certain insulation materials. In that case, some maths might do the trick.
Measure the total thickness of the wall, from the outside to the inside, and the width of a facing brick. The latter can be done near a window or at a corner of the exterior wall. You can assume that the interior brick has a width of 15 centimetres (including plaster). Then you subtract the width of the facing brick and the interior brick from the total width of the wall. This will give you the width of the cavity.
Then you place a folding rule in a weep hole or an inspection opening you made with a drill. Measure how far you can get it into the cavity. Detract the width of the facing brick from this distance and you will get the available width of the cavity. If this figure does not correspond to the width of the cavity you measured earlier, some insulation is present in the cavity wall.
Apply these methods to a number of places on the exterior wall, as the situation in the cavity might not be identical everywhere. If all this maths is doing your head in and you’re still seeking a definitive answer, you could ask a specialist company to conduct a camera inspection.
This article was published on 11-10-2023. Unless expressly provided otherwise, all information you consult or obtain here is entirely without obligation and for information purposes only. The information applies exclusively to Flanders.