Introduce cavity wall insulation

Priority for Completion: High

This recommendation should be included when an assessor finds cavity walls in a property of an age that suggests they have not been fully insulated and they are unable to find evidence that they have been fitted with retro-fit insulation.

Whilst the majority of homes have now been retrofitted where this is possible, it is not at all uncommon for non-domestic buildings not to have been upgraded. This results in wasted energy and higher operating costs. Therefore, we have rated this improvement as one of high priority for completion. Retro-fitting cavity wall insulation requires a specialist contractor but is generally low cost and pays back quickly. It can have a major impact both on reducing heat loss and your carbon footprint.

What is cavity wall insulation?

Cavity walls have an air gap in the centre between the masonry layers. This gap was originally introduced to prevent damp transferring through the wall but it was quickly discovered to also help insulate the wall. Cavity wall insulation fits into this gap and acts to further prevent heat loss through the wall.

The video below explains how one type of cavity wall insulation can be retro-fitted with minimal disruption. In most cases cavity wall insulation can be installed while your premises continues to operate.

NB: We do not endorse this particular product, manufacturer or installer.
Other considerations

Whilst the majority of buildings with cavity walls are suitable for retro-fit insulation, there are some circumstances where it is not appropriate. Unfortunately the current Energy Performance Certificate system does not normally allow this to be considered so your EPC may suggest cavity wall insulation even where it is not suitable. Always choose a reputable installer who will be able to advise on the suitability of your property, the best type of insulation to use and any other work which may need to be completed first.

The installer you choose should be a member of one of the following organisations:


Check that the installer is signed up to a code of professional practice and that the installation is guaranteed for 25 years by CIGA, or through an independent insurance-backed guarantee.