Improve the thermal performance of masonry cavity walls with our range of partial fill cavity wall insulation. Designed to insulate part of the cavity while maintaining a clear residual gap, these products help reduce heat loss and support energy-efficient wall construction.
Our collection includes partial fill insulation products suitable for residential, commercial and new-build projects. Available in a range of thicknesses and thermal performances, they allow installers to choose an appropriate solution for the required cavity width and project specification.
What Is Partial Fill Cavity Wall Insulation?
Partial fill cavity wall insulation is installed against the inner leaf of a masonry cavity wall, leaving a clear gap between the insulation and the outer brickwork.
This residual cavity helps manage moisture and provides a clear space between the insulation layer and the external leaf. Partial fill systems are commonly used where the building design, exposure conditions or project specification requires a maintained cavity.
Partial fill cavity insulation is often supplied as rigid insulation boards, including foil-faced PIR boards, although the correct product will depend on the wall construction and project requirements.
Benefits of Partial Fill Cavity Insulation
Using a suitable partial fill cavity wall insulation product can provide several benefits:
- Helps reduce heat loss through external masonry walls
- Supports improved thermal and energy performance
- Maintains a clear residual cavity
- Available in a range of thicknesses and thermal conductivities
- Suitable for many new-build residential and commercial projects
- Can provide strong thermal performance with a relatively slim insulation layer
- Allows insulation thickness to be selected around the required cavity width
Shop Partial Fill Insulation Products
Explore our selection of partial fill cavity insulation from trusted manufacturers. Our collection includes insulation boards designed to provide reliable thermal performance and straightforward installation within masonry cavity walls.
Popular options within this collection include:
Each product page includes further information about available thicknesses, board dimensions, thermal conductivity and recommended applications.
Choosing the Right Partial Fill Cavity Wall Insulation
When choosing partial fill cavity wall insulation, consider the total cavity width, required residual gap, insulation thickness, target U-value and the thermal conductivity of the product.
You should also consider the building’s location, exposure conditions, wall-tie system and the requirements of the architectural or building specification.
The insulation boards should be installed tightly together with correctly staggered joints to help minimise gaps in the insulation layer. Always follow the manufacturer’s installation guidance and confirm that the selected product is suitable for the intended wall construction.
Partial Fill or Full Fill Cavity Insulation?
Partial fill insulation leaves a clear cavity between the insulation and the outer leaf of the wall. Full fill cavity wall insulation is designed to occupy the full available cavity.
The most appropriate option will depend on the wall design, required thermal performance, cavity width, exposure conditions and project specification.
For alternative products, browse our [full fill cavity wall insulation], [cavity wall insulation], [PIR insulation boards] and [wall insulation] collections.
Order partial fill cavity wall insulation online for delivery across the UK. Browse the products above to compare available sizes, thicknesses and thermal performance for your next insulation project.
