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Cavity Wall Insulation Problems

Cavity wall insulation is just one of the money-saving green initiatives that some energy companies offer to homeowners at no cost. In most cases this means that the householder saves energy and money, as their house stays warmer and the central heating thermostat remains lower. But in some instances property owners have come across cavity wall insulation problems, meaning that there is now a growing industry dedicated to removing cavity wall insulation.

Cavity wall insulation problems

Most of these cavity wall insulation problems happen in certain areas of the UK, where there is a high rainfall with wind and a good chance that that rain will be beating against a south or west elevation. Add to that a close proximity to the coast and you have the perfect conditions for damp. The cavity wall insulation fills the gap between the outside wall and interior walls, so the insulation simply passes the water from outside to inside, as there is no barrier between sodden external walls and internal ones.

cavity wall insulation problems

Image source: Mok9 via Wikimedia Commons

The manufacturers of cavity wall insulation generally recommend that their products are not installed in areas that are close to the coast or that have high levels of wind-driven rain, with areas such as West Wales, West Cornwall, parts of Scotland and the Northwest coast of England being areas regularly marked out as not suitable for the installation of cavity wall insulation. But there are some installers who will ignore these warnings in the name of making a quick profit. Any installer of this kind of insulation should always make an assessment of the home on an individual basis, taking weather factors into account, even in areas that are not impacted by wind-driven rain. Other reasons for not fitting insulation may include a very small clearance between the internal and external walls.


In many cases, the business who has guaranteed and insured your cavity wall insulation will stump up for removal costs should this become necessary. Although there is also the question of the cost of making good any damage caused by damp, which can include a new damp course and re-plastering. This itself can cost upwards of £1,500.

disadvantages of cavity wall insulation

Image source: Matthew G. Bisanz via Wikimedia Commons

If you are considering having cavity wall insulation installed then do make sure that your energy company is using an installer who is registered with a trade body such as CIGA (Cavity Insulation Guarantee Agency) for the sake of your own protection. You can also ask if there are other houses nearby where satisfied customers live who you can speak to. If you have any doubts about whether cavity wall insulation is suitable for your home then be sure to ask the installer. You should be able to gather how reliable they are from the tone of their replies. If they simply brush away concerns and simply continue to talk about how much money you’ll save, then they may not be the best contractor to go with.

If you believe that your cavity wall insulation is causing damp or mould in your home then do get in touch with the original contractor to have the work checked over. They should be willing to come out and check for any problems, but if they are no longer in business then it may be worth posting a job on Rated People to get quotes from trusted damp experts or a cavity wall insulation removal specialist to make an assessment.


Iain Aitch

Iain is a London-based writer who works as a journalist for a number of newspapers and magazines. He has also written two books, one of which is a hilarious lexicon about Britishness – Iain is a Brit through and through!

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  1. I live in a property which I purchased from the Council. When the Caverty Wall Insulation was put in we found that we woke to more condensation on the windows than before and that our Gas bill which is for Basicaly Centreal Heating as we have an electric shower increased and we were told that we were using more Gas whcih we found supprising. My house is Sw facing and in the winter the house was always warm duing the day we didn’t need to put the Central Heating on until the sun went down after it had waremed up in the morning as the non caverty filled walls allowed the heat from the sun to come in and we never had the thermostat above 15 degrees Centigrade which changed after the instalation. I have over 300 books and we had to buy a dehumidifier to keep this room free from condensation: I have now worn out two dehumidifiers and whish the council had done a survey on each house instead of blanket instalation. In summer the house is always cold and yet if you put your hands on the outside walls they are always redhot when the sun is shining winter or summer. We are exposed as there is a green esplande that runs abound our estate and the nearest buildings are down an embankment so we get wind and rain as there is notheing to stop it at the rear: the house the front is more sheltered.
    I certainley would not recomind it to anyone and it also caused my out building to be damp as for some reason that now gets warm.

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