Soffit Insulation

Insulated soffit boards are typically installed in residential and low-rise construction to insulate and close off the underside of pitched roof eaves, gable ends, and overhangs. They help prevent heat loss, protect roof cavities from moisture and pests, and improve airtightness. Soffit board insulation also plays a key role in maintaining proper ventilation, especially in attic spaces where soffit vents and insulation must work in harmony to prevent condensation and mould.

Without soffit board insulation:

• Cold bridging can occur at junctions, reducing energy performance
• Moisture and condensation risks increase
• Soffit vents may be blocked by loose insulation, disrupting airflow and roof ventilation
• Fire spread may be accelerated in unprotected eaves and roof voids

Recommended Manufacturers:

• Kingspan is known for their Kooltherm K110 phenolic boards offering high thermal performance in a thin profile
• AIM Specialise in high-performance boards with facing options for external soffit use

Soffit slabs are used in exposed concrete soffits, basement ceilings, underground car parks, commercial garages, and cold floor zones in residential or mixed-use buildings. They're often applied directly to concrete substrates using mechanical fixings or adhesive. It help's retain heat within the conditioned part of the building and protect against the thermal loss through unheated zones. They also offer acoustic dampening in underground car parks and fire resistance for exposed ceilings.

Risks if not used:

Omitting soffit slab insulation can lead to:

• Significant heat loss through ground floors and uninsulated basements
• Increased heating costs due to thermal bridging
• Condensation forming on cold ceiling surfaces
• Poor acoustic performance and echo in large open concrete areas
• Fire safety compliance issues in exposed concrete structures

Recommended Manufacturers:

• Rockwool offers non-combustible A1-rated stone wool slabs for excellent fire and acoustic performance
• Knauf delivers glass mineral wool slabs ideal for cost-effective thermal insulation in soffit applications
• ARC provides fire-rated soffit and perimeter solutions for thermal, acoustic, and fire protection in building perimeters

Not all soffits are the same, our range covers everything from asbestos insulation board replacements to external soffit insulation, fire-rated baffle boards, and insulated soffit panels for cladding systems. We also supply accessories such as fixings, vents, and insulation baffles to prevent blocked soffit vents and ensure compliance with Part L and Part B of the UK Building Regulations.

Whether you’re insulating a garage, protecting a concrete soffit, or upgrading your roof eaves, we can help you find the right solution. Contact our technical team for advice on soffit vent compatibility, fire detailing, or installation guidance