Problems with Wet Cavity Wall Insulation Explained

Do you have problems with damp cavity walls?

After our recent TV campaign, we are being increasingly contacted by customers who are having issues with cavity wall insulation damp or condensation and wondering how best to solve them. It is not only solid wall properties that can suffer from condensation and damp penetration. If cavity wall insulation is badly fitted or gets wet it can cause a huge number of problems.”

Condensation on Cavity Walls

Condensation on cavity walls often presents itself as black mould spots and is caused by the warm air inside the house condensing on cold wall areas. If cavity walls are filled properly by a reputable company you should not be experiencing this problem however there are a couple of cases in which this can happen:

Firstly some of the earliest cavity wall insulation, installed over 25 years ago and employing more rudimentary materials, may have slumped in the cavity wall, leaving cold spots that may be causing cavity wall condensation.

More recently, unfortunately, we see many cases of poorly installed cavity wall insulation where the wrong drill pattern or blowing pressure has left void spots which may lead to condensation.

We have also heard of shameful practices where cavity walls have been drilled but not one fibre of insulation is installed as the company is only interested in making a quick profit. As the industry is not 100% regulated with invasive drilling checks there has so far been no way of checking if this has happened, but is becoming more apparent that lack of fill in part or all of some properties has occurred.

Damp Cavity Walls

Damp in cavity walls is noticeable as the internal plaster finish will start to blister and crumble as the moisture content rises. There are a number of causes for this:

Cavity wall insulation may have been damaged during flooding. After the winter we have just had this is a common occurrence.

Sometimes broken or poorly performing rainwater goods may have allowed water to penetrate the cavity.

The property may be located in an area of high exposure to wind driven rain and standard cavity wall insulation should not have been installed in the first place.

In cases of cavity wall condensation or damp  the only real course of action is to have the cavity wall extraction, and if suitable re-filled.

It is now apparent that hundreds of thousands of home owners across the UK will need remedial work that will consist of a full extraction of the Cavity Wall Insulation and could well mean a whole host of other repairs and replacements directly caused by the install, costing in excess of £10,000.

Mortgage lenders are also looking at properties which have had CWI installed and can devalue a property by as much as £30,000 if a valid CWI examination certificate is not available.

If you’ve got issues of any nature with your Cavity Wall Insulation that may be down to the installer not following proper guidelines as to the install, contact us for a free, no obligation review.

Contact Wall Cavity Claims today on free phone 0800-8-654321 or visit

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