Improve the thermal performance of external masonry walls with our range of cavity wall insulation. Designed for installation between the inner and outer leaves of a cavity wall, these insulation products help reduce heat loss, improve energy efficiency and support comfortable indoor temperatures throughout the year.
Our collection includes both full fill and partial fill cavity wall insulation from trusted manufacturers. With a variety of materials, thicknesses and thermal performances available, you can find a suitable solution for residential, commercial and new-build construction projects.
What Is Cavity Wall Insulation?
Cavity wall insulation is installed within the space between the inner blockwork leaf and outer masonry leaf of an external wall. It creates a continuous layer of insulation that helps slow the transfer of heat through the building envelope.
Depending on the wall construction and project specification, the insulation may fill the entire cavity or leave a clear residual gap between the insulation and the outer leaf.
Cavity wall insulation is commonly available as rigid insulation boards or water-repellent mineral wool batts. The correct product will depend on factors such as the cavity width, required U-value, exposure conditions and specified installation method.
Types of Cavity Wall Insulation
The two main cavity insulation systems are full fill and partial fill.
Full Fill Cavity Wall Insulation
Full fill cavity wall insulation is designed to occupy the full available width of the cavity. This helps maximise the amount of insulation within the wall while keeping the overall construction relatively compact.
Full fill products may include water-repellent mineral wool batts or rigid boards specifically approved for full fill cavity applications.
Explore our [full fill cavity wall insulation] collection to compare suitable products, thicknesses and thermal performance.
Partial Fill Cavity Wall Insulation
Partial fill cavity wall insulation is fixed against the inner leaf of the wall while leaving a clear residual cavity between the insulation and the external masonry.
Partial fill systems commonly use rigid insulation boards and may be specified where the wall design, exposure conditions or construction requirements call for a maintained cavity.
Browse our [partial fill cavity wall insulation] collection to find insulation boards in a range of thicknesses and thermal conductivities.
Benefits of Cavity Wall Insulation
Choosing suitable cavity wall insulation can provide several benefits:
- Helps reduce heat loss through external masonry walls
- Supports improved building energy efficiency
- Can help achieve the target U-value for a project
- Available for both full fill and partial fill wall systems
- Suitable for residential and commercial construction
- Offered in a variety of thicknesses and thermal conductivities
- Helps create a more comfortable and consistent internal temperature
Shop Cavity Wall Insulation
Explore cavity wall insulation products from leading manufacturers, with options suitable for a wide range of masonry wall constructions.
Products within this collection may include:
- Full fill mineral wool cavity batts
- Full fill rigid insulation boards
- Partial fill PIR insulation boards
- High-performance cavity wall insulation
- Products available in multiple thicknesses and board sizes
Each product page provides further information about dimensions, thermal conductivity, available thicknesses and recommended applications.
Choosing the Right Cavity Wall Insulation
When selecting cavity wall insulation, consider whether the wall requires a full fill or partial fill system. You should also check the overall cavity width, insulation thickness, required residual gap, target U-value and thermal conductivity of the product.
Other important considerations include the building’s location, exposure to wind-driven rain, wall-tie system, masonry type and architectural specification.
The selected insulation should be suitable for the intended cavity wall construction and installed in accordance with the manufacturer’s instructions. Boards or batts should be closely fitted to help minimise gaps and maintain a continuous insulation layer.
Full Fill or Partial Fill Cavity Insulation?
Full fill insulation occupies the full available cavity, while partial fill insulation leaves a clear gap between the insulation and the outer masonry leaf.
Neither system is automatically suitable for every project. The best choice will depend on the wall design, cavity width, thermal requirements, exposure conditions and building specification.
Compare our [full fill cavity wall insulation] and [partial fill cavity wall insulation] ranges to find the most appropriate solution for your project.
For other building insulation products, browse our [wall insulation], [PIR insulation boards] and [mineral wool insulation] collections.
Order cavity wall insulation online for delivery across the UK. Browse the collection above to compare products, sizes, thicknesses and thermal performance for your next construction project.
