Cavity wall insulation has come under quite a bit of scrutiny over the last few years, some of which is deserved but not all.
If you have a cavity wall it means that you have 2 walls, built parallel to each other with a gap in between (the cavity), tied together with small pieces of metal called wall ties. It is a strong, robust type of construction that is widely used around the world. The cavity is designed to help improve the energy efficiency of the house and is also there to protect the inner wall or ‘skin’ from moisture. So, if that’s it’s job, why would you fill this gap?
Whilst the air within the cavity provides a thermal barrier to the outside, it is not as effective as the insulation material that is used to fill the cavities and with the Climate Change Act (2008) mentioned in Energy and the home, the increased levels of energy efficiency produced by filling cavities meant that each home with the cavity filled was using less energy to heat it to the same temperature than those without. Because of this, it became widely available and supported by government funding, which is where many ‘installers’ looked to take advantage of and make a quick profit.
There are many horror stories linked with cavity wall insulation that have come from houses that probably shouldn’t have had their cavity filled in the first place or were insulated poorly by someone who wasn’t properly trained to install the wall insulation. These are the cases that you might have read about and that have cost the home owners £100,000’s in damages and repair bills because it makes a good headline for a newspaper. The chances are there were lots of other problems with the property rather than just the cavity wall insulation.
All of that aside, a property must be suitable for the insulation to be installed otherwise there will be problems from the start. This is why it is very important to find a credible company with a good track record of installing the insulation. These companies will often provide a guarantee for their works of up to 25 years which can be passed on to the next home owner if you decide to move within that time. It can be worth shopping around and getting a few quotes as well as noting which companies will undertake a site visit to check the house for suitability. Your installer should be a member of one of these organisations:
- The National Insulation Association (NIA)
- The Cavity Insulation Guarantee Agency (CIGA)
- The British Board of Agrément (BBA)
Some of the guarantee will not cover you if you do not keep the exterior condition of the property up to a satisfactory weatherproof standard that will stop damp related issues as the installer may say that it is not their guaranteed work that is the cause of the problems but rather the lack of general maintenance to the property. This also applies if you are going to carry out any additional works to the property such as installing a log burner that has a flue going through the wall. It is always best to check with the guarantor what you are able to do before carrying out any works.
You should also note that cavity wall insulation is deemed ‘notifiable building works’ and if you are considering undertaking this work then you do need to submit a building notice to the building control body of the local council.