Cavity Wall Insulation

The use of retro cavity wall insulation can improve the insulation properties and reduce the rate of heat loss; it reduces the ‘U value’.

Full investigation of the suitability of it's use should be carried out and specific advise be sought before from a Chartered Surveyor, independent of the contractor carrying out or quoting to carry out the work.

RICS Scotland has issued the following press statement as below.

RICS Scotland Building Surveying Professional Group wish to highlight a growing concern in relation to the inappropriate application of cavity wall insulation for domestic dwellings.

Within Scotland a large portion of our existing domestic housing stock is unsuitable for cavity wall insulation and the installation of cavity fill could have a detrimental effect on the core building fabric of such properties.

Building Surveyors support the improvement of insulation standards and carbon usage reduction across the whole spectrum of property types and indeed many of RICS members are at the forefront of such measures.

Even where a house is suitable for the installation of cavity wall insulation this should be carefully considered and appropriately detailed. With this in mind we wish to highlight the following five key considerations for home owners across the country:

* Consider your home's age and construction type – Homes built after 1990 are likely to have some form of insulation within the external walls and under no circumstances should the cavity of a timber frame dwelling be filled

* Consider the exposure and orientation of your home – Some walls exposed to driving rain can be unsuitable for cavity wall insulation, given the design of cavity walls rainwater is expected to penetrate into the cavity.

* Consider the steps necessary to close cavities – Ascertain how cavities will be closed to keep the insulation material between the walls. This is particularly relevant if your home forms part of a terrace or is semi detached. Cavities may also have to be closed in the attic and sub-floor area and checks should be made prior to installation.

* Consider the fill material - Mineral fibre and EPS beads can be used in all areas of Scotland in the correct circumstances. Urea Formaldehyde Foam should not be used in server weather zones including costal areas and as such is not suitable for use in Scotland as identified in the relevant British Standard.

* Consider a Thermograpic Survey - Request a survey of your property with a thermograpic imagery camera before and after cavity wall insulation has been installed. The pre-installation survey will identify the extent of heat loss from your external walls and the post-installation survey will confirm that heat loss has been reduced and perhaps more importantly identify any gaps or voids in the cavity fill which will be apparent as cold spots.

Given the large amount of government funding which is being expended in this area a complete home insulation industry has developed.

Cavity wall insulation does have a place in our continued moves to reduce carbon emissions and to combat matters such as fuel poverty but its not a panacea to reducing domestic energy usage and care should be taken before altering the anatomy of external cavity walls without fully considering the possible long term effects on the whole property.