Cavity wall insulation and damp problems

The growth in cavity wall insulation installations to improve energy efficiency and heat retention in homes across the UK has unfortunately resulted in an increase in damp problems in many properties.

Our guide will explain this link between damp and cavity wall insulation and how it can cause problems like penetrating damp.

Cavity wall insulation refers to the process of filling the gap between the outer wall and inner wall (known as the cavity) with insulation material such as foam, mineral-wool fibre or beaded polystyrene.

The reason why it is a benefit is that it helps prevent the flow of heat from inside the property to the cold outside. A great idea in theory, but it is not without its problems if you have not used a qualified or industrial approved contractor.

Damp problems relating to cavity wall insulation usually stem from it being inappropriately and incorrectly installed or a lack of attention to the suitability of installing the cavity wall insulation in the first place.

What we mean by the latter is that if you have damage to the external wall brickwork or render that was not been picked up before the installation, once the cavity wall insulation has been installed it will effectively act as a bridge for moisture between the inner leaf and damaged external wall. The most common outcome of this moisture bridge is penetrating damp.

If there are gaps in the insulation then you will likely be left with cold spots on the wall which will attract condensation and perhaps mould problems.

Amongst the various signs of penetrating damp affecting internal walls, the most common is the appearance of blotchy patches of damp on the surface of the internal wall that may get darker and larger in the event of heavy rainfall. In addition to this, the other signs to look out for are:

• Paint and plaster deterioration
• Water staining
• Damp spots or condensation on the interior wall
• The appearance of black mould
• In extreme cases, you may find water dripping and leaking through the wall

Evidence of dampness on internal walls does not necessarily point to penetrating damp straight away. There are other types of damp you might want to consider like condensation.

What we would suggest, however, is that if there is no obvious source of the water ingress into the property leading to penetrating damp and you are struggling to determine why you are suffering damp on your internal walls,  then it is recommended that you should contact a damp specialist such as ourselves to organise a damp survey.

Below is not an extensive list, however, is a guide to help you consider whether cavity wall insulation is a cost-effective solution for your property and will it avoid damp problems if installed. Ask yourself these questions and ensure you ask the same questions to whoever may be installing the cavity wall insulation:

• Is your property is severely exposed to wind-driven rain?
• Does your property lack adequate shelter from trees or other buildings?
• Are your external walls poorly constructed or poorly maintained?
• Do your external walls have damaged bricks or rendering?

As we mentioned previously, cavity-wall insulation will not necessarily cause damp problems, however, from time to time, it does happen and it is certainly worth asking the above questions before considering the installation.

If it is already too late to ask the questions and you suspect you are suffering damp issues due to the cavity wall insulation, then we would suggest you take a look at our penetrating damp treatment page to help you understand what you need to do to rectify the issue.

Companies associated with industrial bodies such as the National insulation Association (NIA) typically have cavity insulation guarantee agency to cover instances where something has gone wrong.

If it is the case where you have not used an industry approved contractor for the cavity wall insulation, then you will need to contact a damp-proof company to rectify the issue.

If you are having difficulty identifying the source of water ingress leading to the penetrating damp or condensation on internal walls or are concerned that your property is suffering from some of the related issues with penetrating damp, then we are here to help.

Our experienced and qualified team of damp surveyors are market leaders in identifying, and diagnosing damp problems on both the outer leaf and inner leaf solid walls.  If it is the case that penetrating damp has been identified by our surveyor, we will pull together a cavity insulation treatment plan to repair the wall insulation and restore your walls to their natural dry and safe state.

If you think your cavity walls might be causing a damp problem and want to consult with a specialist, then we are here to help.

Simply give us a call, find your local branch or click the button below to book a survey. Our highly trained and qualified surveyors will be able to access any areas of concern, offer you help and advice and if necessary, recommend any appropriate solutions to ensure you can insulate your house and reduce heating bills without creating additional problems.