The Rockwool thermal insulation cavity batts are a full fill stone wool insulation solution for application in masonry cavity wall constructions such as home extensions. Thermal insulation cavity batts are Euroclass A1 non-combustible water repellent and vapour permeable allowing the material to breathe and will not harbour mould. The Thermal Insulation Cavity Batts are easy to handle and install allowing for a close fit against brick and blockwork.