Cavity Wall Insulation

Cavity wall insulation improves a building’s energy efficiency by reducing heat loss through external walls. It involves insulating the gap between the inner and outer leaves of a cavity wall, helping to maintain indoor temperatures, lower heating costs, and enhance comfort. The type of insulation used depends on the building type, moisture levels, and thermal requirements.

Popular products for full and partial-fill cavity walls include:

Celotex CW4000 Partial Fill Cavity Wall Insulation Board     
Knauf DriTherm 32 Cavity Insulation Slab  
Rockwool Full Fill Cavity Batt
Rockwool High-Performance Partial Fill Cavity Slab

The difference between partial and full-fill cavities:

Partial-fill cavity wall insulation involves installing rigid boards or slabs against the inner leaf of the cavity, leaving a small air gap. This method is preferred as it allows for moisture control while meeting Building Regulations. The air gap helps prevent water from penetrating the insulation, reducing the risk of dampness issues.

Full-fill cavity wall insulation fills the cavity to maximise heat retention. It is typically installed in properties where the cavity was previously uninsulated, offering a cost-effective way to improve energy efficiency.