Product description

Cavity insulation is essential to provide weather-tight protection against inclement weather. The potential for damage caused by moisture can compromise insulation performance, so the ROCKWOOL® Full Fill Cavity Batts provide a great, water resistant solution for new build or extension projects.


With over 30 years’ proven service in all types of climate, temperatures and exposure, ROCKWOOL® Cavity Batts make a great solution for new builds or extensions – from homes to commercial. The non-combustible, fire resistant solution has been developed for the requirements of new build construction and contains water repellent additives. The mineral wool insulation Full Fill Cavity Batts critically prevent moisture transmission and maintain insulation for the long term. The Full Fill Cavity Batts are lightweight and easy to handle, making installation simple and providing a close fit against brick and blockwork, whilst also adapting to imperfections in the cavity wall. As a rigid full-fill insulation solution, the product ensures a resistance to fire spread between and within cavities. It acts as a barrier when tightly fitted between masonry leaves where an insulated wall connects with an uninsulated wall cavity.



BBA certified for all exposure zones /

Non-combustible (Euroclass A1)


  • Easy to install – the Full Fill Cavity Batts do not require TCBs.
  • Water repellent – the product maintains dryness and actively minimises moisture transmission as the orientation of the water repellent fibres prevent water crossing the wall construction. This is provided that the batts are correctly installed and sound building techniques are applied to the cavity wall construction.
  • Durable – with no sagging or slumping, ROCKWOOL Cavity Batts have over 30 years’ proven service, providing effective insulation for the lifetime of the building.
  • Thermal protection - effectively acts as a durable cavity barrier with a thermal conductivity (lambda) of 0.037w/mk.
  • Flexible – to meet the requirements of a wide variety of projects, it is available in a range of thicknesses.
Brochures, press releases, catalogues, technical data sheets