ROCKWOOL Thermal Insulation Cavity Slab 32 is a full and partial fill stone wool slab designed for the thermal insulation of masonry cavity walls. Suitable for use in new builds, renovations or extensions, the lightweight slabs are easy to handle and simple to install providing an accurate fit against the blockwork. ROCKWOOL Cavity Slab 32 has a more efficient fibre structure that increases the density of air pockets trapped within each slab. This results in an improved thermal performance when compared to typical stone wool products.