Cavity Wall Insulation

Un-insulated cavity walls can lose a large proportion of the heat you produce. If you insulate cavity walls you will reduce your carbon emissions and heat loss, and will save around £125 a year on your utility bills.

Can I have cavity wall insulation?

Cavity walls became common place after 1920-1930; so if you house was built after this period then it is likely you will have cavity walls. A cavity wall describes how your external walls are constructed, with two separate layer of brickwork or block work with an air space in-between. Insulating your cavity walls means filling that gap to provide improved insulation properties of the walls.
Do not worry if you cannot identify what type of walls you have, as cavity wall insulation installers generally offer a free no obligation site survey, where they will identify if your property is suitable for a filled cavity wall.

Should I insulate my cavity walls?

Cavity wall insulation is an effective way to improve the energy efficiency of your home, reducing your heating consumption, energy bills and carbon emissions.
The debate in regard to whether cavity wall insulation is a good idea continues with opinions split on the issue. The majority of properties with filled cavities do not experience any problems, and the Government continues to promote the installation of cavity wall insulation with wide spread grants.
If every domestic property in the UK had cavity wall insulation installed, where applicable, we would save around £700 million and nearly 4 million tonnes of CO2 each and every year.
Manufacturers of the materials used in cavity wall insulation say they withstand vermin, fungi, rotting, and are water resistant. The Cavity Insulation Guarantee Agency (CIGA) provides independent 25-year guarantees for Cavity Wall Insulation fitted by registered installers in the UK.

Costs of cavity wall insulation

The cost varies amongst installers and can be dependent on the size and type of property (approx £200 - £400). You may be entitled to a grant for cavity wall insulation, which means it could be installed free! If you are unable to claim a full grant, you may be able to receive a partial grant towards the insulation cost.

Cavity wall insulation cannot be installed if:

  • You live in a flat and the neighbours cannot agree on the installation. The walls must be filled from the ground to the roof, they cannot be partially filled
  • There are any signs of damp. Damp problems must be cured before cavity wall insulation can be installed.
  • The cavity width is less than 50mm or 2".
  • The property is of timber or steel framed construction
  • The cavity contains rubble inside
  • The damp course is not functioning properly
  • If ventilation is poor and a vent or air brick cannot be fitted.
If you are in doubt with any of the above, be sure to contact and consult a cavity wall insulation specialist.