Our recommended masonry cavity wall solution is full-fill, either injected (Supafil) built-in using slabs (Earthwool DriTherm Cavity Slabs).
Full-fill systems not only provide the best U-value to wall width ratio but are also the lowest in cost. Even with dense concrete blocks it is possible to achieve very high thermal performance in a manageable wall width.
Masonry cavity walls built using our Supafil and Earthwool DriTherm solutions do not require cavity barriers, and full-fill systems can be installed in all types of buildings across the built environment, as detailed in their British Board of Agrément (BBA) Certificates.
Supafil solutions are loose glass mineral wool insulation materials which are injected into existing or newly built masonry cavity walls. They require no mixing on site and are dry when installed, adding no water to the building. Our Supafil range is available only through approved installers fully trained by Knauf Insulation and approved by the British Board of Agrément (BBA). A list of approved installers is available on request.
Earthwool DriTherm Cavity Slabs are a range of lightweight semi rigid or rigid slabs of glass mineral wool with a water repellent additive. They are manufactured to fit between wall ties at standard vertical spacings.