Cavity Walls - Fully Filled

Brick and block is a popular construction type, with a cavity wall construction. Building Regulations can be achieved by part or full fill insulation, depending upon preferred construction type.

Technical information

When complying with current Building Regulations and looking to build a traditional cavity wall, the construction should consist of an external skin of 102.5mm facing brick with a 100mm cavity fully filled with Knauf DriTherm 32 Ultimate cavity insulation and an internal skin of 100mm Celcon Standard aerated blocks.

Above windows and doors install insulated cavity lintels. Cavity trays should be installed with weep vents incorporated within the external skin at 450mm centres.

There are no requirements for fire stops as Earthwool Dritherm products are completely non-combustible and fully fill the cavity.

Hints & Tips

Ensure cavity insulation batts are kept clean and dry during construction and any mortar that may fall on them is cleaned off.

Ensure mortar snots are removed from the cavity side of the brickwork/blockwork.

To further reduce the transfer of heat away from the inside of the building it is recommended that below the DPC the cavity is fully filled with 100mm PIR insulation reducing thermal bridging.

Ensure correct positioning and quantity of wall ties are incorporated within the wall construction.

Using a fully filled cavity will decrease the passage of sound through a wall in comparison to a partially filled cavity.

Cavity insulation within the gable walls should always be taken up to ridge level to future proof the property for the possibility of the roof void being used as a habitable space.