Cavity Wall Insulation

Cavity Wall insulation is a type of insulation applied within the cavity walls (usually the exterior) of residential and commercial buildings. Many people are familiar with the form of cavity wall insulation that involves blowing small foam pellets into the cavity of existing houses, but modern houses are instead often built using Cavity Slab insulation batts - such as Knauf Dritherm 32 and 37. Instead of being applied retroactively, this is added during the process of constructing the wall - literally from the ground up. It is designed to “friction fit” between the cavity walls, in between the steel wall ties, and is an effective thermal insulation.

We stock a range of Mineral Wool Insulation such as Rockwool Insulation, Knauf Insulation in a range of thicknesses that reflect the most common depth of wall cavities:

50mm, 75mm, 85mm, 100mm, 125mm, 150mm - the most popular thicknesses are 100mm, 125mm and 150mm. 

Our rigid Cavity Wall insulation (such as Celotex insulation and Recticel insulation) comes in slightly narrower sizes (usually around 10mm narrower) which allows room for a 10mm residual cavity within the wall - helping with ease of installation of rigid boards, and to accommodate any mortar spread. 

Cavity Wall Insulation is applied within the cavity of masonry cavity walls during their construction. It is built up at the same time as both sides of a cavity wall and added as the courses of masonry and corresponding wall-ties are added. It is typically cut into 455mm or 600mm sheets designed specifically to fit between these ties. Ensure you select a thickness that corresponds to the space of the cavity - full-fill insulation is designed to have full contact with the wall, whilst partial-fill insulation is typically intended to allow an air gap.