Cavity wall insulation is a great way to keep your home warm and cut your energy bills, but there are instances where cavity wall insulation is not the right solution and can actually lead to big problems further down the line.
Why were cavity walls introduced?
Cavity wall properties began to be built in the 1930s as a way of stopping moisture penetrating the external walls. The cavity walls were built by laying two skins of brick parallel to one another with an air space between them. The advantage of this type of wall was that water could penetrate the outer skin of brick, but then when it reached the void there was no way it could cross to the inner leaf, ensuring that damp never made it into the home.
In the 1970s, oil prices sky-rocketed and this saw energy bills increase, so the decision was taken to utilise the cavity for an additional purpose – house insulation. The aim of the cavity wall insulation was to slow heat loss, thereby helping lower energy bills. Today, cavity walls are still a popular building type and it is a requirement within building regulations that the cavity is filled with insulation to help limit heat loss.
Building a property and including cavity wall insulation at the same time is pretty easy, but obviously there were millions of cavity-walled properties built between the 1930s and 1970s without insulation. In the 1980s, a method was developed that allowed these unfilled cavity walls to be injected with insulation and millions of properties have been injected with insulation since.
If you do a quick search of the internet, you will find many people who are dead against cavity wall insulation – the reason for this is that in some cases the cavity wall insulation can cause problems!
Problems caused by cavity wall insulation
There are a few common problems caused by cavity wall insulation that are discussed in detail below:
Urea-formaldehyde was used in the cavity
When cavity wall insulation first began several decades back, a particular type of foam was used that gradually breaks down over the years, releasing a toxic urea-formaldehyde gas. If you have this type of insulation you may want to get it removed since it could have health implications as the gas is carcinogenic. The other problem with this particular type of cavity wall is that as it breaks down it slips down the cavity leaving the top of the cavity insulation free, so heat loss can occur.
The good news is that as a result of modern standards, this type of insulation is no longer installed!
The building is not suitable for cavity wall insulation
Millions of properties benefit from the energy savings produced by cavity wall insulation, but not every building is suitable. If the building is located in an area of the UK that has high exposure to wind and rain, then cavity wall insulation is probably a bad idea. Remember one of the primary purposes of the cavity is to drain water away from the inner leaf of the brick, but if the cavity is filled, this new insulation can create pathways for water to cross over the cavity and cause damp in the house.
Incorrect property type for insulation
Rogue installers have been known to install insulation in properties that are not suitable, like steel framed and timber framed properties or those with porous bricks that allow the insulation to get damp. We get a huge number of phone calls from homeowners who are unable to sell their property and buyers unable to get a mortgage due to the presence of cavity wall insulation in timber framed properties.
Flood or Fire Damage to Insulation
If the insulation gets wet or otherwise damaged by an unforeseen event like flooding, the insulation may need to be removed. An example might be where the water tank bursts or where there is a chimney fire. Here, replacement insulation is likely to be recommended once the defective cavity wall insulation is removed.
Poorly installed cavity wall Insulation
The final reason is perhaps the most common problem associated with cavity wall insulation and is the most common reason why people look to have cavity wall insulation extracted. If wool is being injected into the cavity and the installer doesn’t take care then there is a high chance there will be gaps in the wall where there is no insulation. This can cause damp, so it may be recommended that the insulation should be removed.
Likewise if beads are injected into the cavity they should always be injected with some sort of adhesive to help hold the beads together when they are in place. Unfortunately this process takes far longer than simply injecting the cavity wall insulation beads without glue, so many installers ‘forget’ to do this as it allows them to race from job to job.
The good news is that cavity wall insulation can be removed with minimal fuss. If suitable/appropriate, new insulation can be injected into the cavity or a completely different type of wall insulation can by used leaving the cavity empty (e.g. external wall insulation).
How can you remove cavity wall insulation?
It is currently possible to extract a range of insulation types, including mineral fibre, expanded polystyrene (beads), and urea formaldehyde.
Where wool insulation needs to be removed, it is sucked out by a large vacuum machine. In the case of glued beads or urea formaldehyde, to extract this type of insulation from the cavity, bricks are removed and the insulation is broken up using a specialist type of machinery. Once the insulation is broken down into smaller parts it is sucked out, similar to wool extraction.
The high pressure vacuum machine is used to suck the insulation out of the cavity, and the old insulation is bagged and removed from the property, leaving the cavity completely clear of any old cavity wall insulation.
If you would like to see a cavity wall insulation removal case study, click on the link below – it goes into more detail of the cavity wall extraction process.
We have nationwide cavity wall extraction partners who between them cover every postcode, so you if you are interested in getting your cavity wall insulation removed then fill in the form below and we will be in touch. Prices vary depending on the type of insulation that requires extraction and the size of the job – the good news though is that in many cases we can use readily available data to produce accurate desktop quotes without the need to visit the property first.
Cavity wall insulation does work – just not every time
It is worth reinforcing the point that in the vast majority of cases cavity wall insulation is a great way to insulate your home – it is relatively inexpensive and the payback is normally just a couple of years. The truth though is that not every property should have cavity wall insulation installed, so if in doubt always seek professional advice to see whether it is right for your property.
If you would like to read more about cavity wall insulation, see our full guide here.
Extracting cavity wall insulation
Need to remove cavity wall insulation from your walls? We have scoured the country for the best tradespeople, so that we can make sure we only recommend those we really trust.
If you would like us to find you a local insulation extraction expert, just fill in the form below and we will be in touch shortly!