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Cavity Wall Insulation

Retrospective cavity wall insulation is carried on homes where there is a space between the internal and external walls. The insulation is blown into the cavity walls using high pressure air.  Before an installation can be completed it is essential that the cavity is surveyed for any debris.

Having your properties cavity walls filled with blown insulation material will reduce your energy bills and reduce carbon emissions. It can also help prevent damp and condensation.

How is cavity wall insulation installed?

Cavity wall insulation is installed by using machinery to blow expanded polystyrene beads into the cavity using high pressure air. This creates a long lasting and effective insulation barrier within the voids of the property.


The cavity walls will need to be inspected prior to the installation commencing. This is to ensure that there are no debris within the cavity. The exterior brick work must also be in sound condition to prevent water ingress. If any electrical cables are found in the cavity an alternative material such as blown glass wool fibre should be used in place of expanded polystyrene beads.

Drill Holes

Next 22mm holes are drilled into the brick work at strategic locations to enable the blown insulation material to reach all of the nooks and crannies within the wall. This is very important as filling the entire cavity will ensure that there are no cold spots.

Blowing insulation

The insulation material will be blown at high pressure into the pre drilled holes. The cavity will be completely filled with solid, compacted insulation material, the entire property is completed before any of the holes are refilled.

Fill in holes

All of the holes will be filled with cement based filler. Once the filler has cured the installation is complete. Most installations take half a day to complete.

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