The benefits of cavity wall insulation are widely advertised – it’s cheap to install and completely hidden, it cuts heating bills and helps improve the environmental performance of your property. However, many people are suffering from damp problems linked to cavity wall insulation surveyor that’s not up to the standard it was promised.

If you’re suffering from penetrating damp caused by CWI, our expert surveyors can help. Our damp surveys can pinpoint the cause of the problem and recommend a solution.

Cavity walls were first introduced in 1932 as a way of stopping internal penetrating damp by creating a gap between the external brick wall and the inner masonry. This meant that any water absorbed by the bricks would pass down the gap and not penetrate the inner leaf of the wall, thus avoiding the need for a chemical damp proof course (DPC).

When the walls are filled with foam or mineral-wool fibre or beaded polystyrene it’s called cavity wall insulation. This is popular with house builders because it’s relatively cheap to do and can be installed quickly and easily. This is particularly true if the house is new build, because the requirement to insulate is now built into building regulations.

There are certain criteria which need to be met for cavity wall insulation to be appropriate for a property, including whether it is a detached or semi-detached home and that the cavity is at least 2 inches wide. It should also be in good condition, free from any obvious damp patches or rot. The insulation itself is normally injected into the cavity using a machine and can either be foam or mineral wool fibre depending on your needs. The installer will normally arrange for The Cavity Insulation Guarantee Agency to issue a 25 year warranty in respect of the installation.

Your surveyor will conduct a full visual appraisal of the property and inform you as to whether cavity wall insulation is present, the constriction details and if the brickwork has moved or there are step/staggered cracks in the walls. They will then use a metal detector to locate the existing cavity wall ties and drill an inspection hole or remove bricks if necessary near to each of the cavities to inspect with a borescope.

Once the inspection is complete they will write their report and if there are signs of cavity wall insulation being present they will advise you on the fee for a full invasive inspection with a view to removing the insulation and repairing the affected walls.

The effectiveness of the insulation can deteriorate over time due to various factors such as settlement or an incorrectly sized or positioned borehole. This can create gaps or ‘filler holes’ which can reduce the efficiency of your insulation and lead to problems such as penetrating damp.