Is There Correlation Between Increased Damp Complaints and Cavity Wall Insulation?

With energy costs on the rise and showing no slow-down, homeowners are looking to make their homes more energy efficient. Looking for solutions that will help them save them money in the long-term while staying warm and comfortable. There are a number of suggested ways that you can do this, from reducing your thermostat setting by even a single degree to sealing drafts around doors and windows.

One solution seems to come up so much, even the UK government has got behind it. Cavity Wall Insulation. But is it all it’s promised to be? Some homeowners who have had cavity wall insulation had started to complain of problems with mould and damp (often incorrectly identified as rising damp). Quotes from some afflicted homeowners mentioned “…a year or so later, cracks starting to appear” and that the house looked like it was deteriorating under damp and mould.

At this time, no accredited research has been carried out, so while no official correlation can be confirmed between increased damp and cavity wall insulation. We look at what could be causing the problem.

What is a Cavity Wall?

Cavity Walls exist in the majority of properties built between 1930 and 1990. The structure is identified by the “cavity” or gap left between the face bricks and masonry blocks. The purpose of the cavity was to prevent wind-driven rain from penetrating the internal rooms of the building. Instead, rainwater would ingress through the face bricks and drip down into the foundations or evaporate. While cavity walls were mainly installed in coastal properties, it was found the cavity offered slight thermal protection and soon spread to construction across the country.

What is Cavity Wall Insulation?

Cavity wall insulation is the practice of filling these cavities (also known as “retrofill”) with a thermal insulation to trap heat in the walls. The material used varies between companies, but typically is a type of “blown mineral-wool fibre” that – as the name suggests – is blown into the cavity wall via small holes in the external brick.

How Does Cavity Wall Insulation Affect Damp?

This blown-fibre material, although reported as waterproof, has been found to actually absorb and retain water. Depending on the amount of rainfall you experience, this material is now sat between your face bricks and masonry blocks of the interior wall in various stages of dampness. This moisture can very quickly spread to internal walls and can be difficult to remove.

While Cavity Wall Insulation is effective at keeping heat in the property, it’s not suited to every property across the country. Instead, if you are offered Cavity Wall Insulation, request a third-party survey to assess if your property will benefit or if it could have negative effects.

If you suspect your house is suffering from damp or you require further information on rising damp quotes, please get in touch.