Fire Resistant Insulation

Fire Resistant Insulation Types

Fire resistant and fireproof insulation is designed to resist the spread of flames, limit smoke emission, and in the case of stone and glass mineral wool, achieve full non-combustibility. It is used in walls, partitions, floors, loft conversions, and cavity walls in domestic and commercial buildings, and is increasingly specified following changes to UK fire safety legislation. Insulation UK stocks a comprehensive range of fireproof insulation materials from Rockwool, Knauf, Superglass, and Tekfon, with competitive trade pricing and fast UK-wide delivery on every order.

Rockwool Fireproof Insulation

All Rockwool products are Euroclass A1 non-combustible and deliver combined thermal, acoustic, and fire performance in a single product. Rockwool RWA45 (45kg/m³, lambda 0.036 W/mK) is the UK's most widely specified acoustic and fire resistant slab, available from 25mm to 100mm in 1200 x 600mm format. It friction-fits between timber studs and floor joists and is the standard choice for party walls, separating floors, and acoustic partitions where fire resistance is required.

Rockwool RW3 is a higher density slab for applications demanding both maximum acoustic performance and fire resistance, available from 25mm to 100mm.
Rockwool Flexi is a multi-purpose stone wool slab with a flexible edge for a tight friction-fit without cutting. Available in 400mm and 600mm widths from 50mm to 100mm, it has been specifically tested to provide 60 minutes fire resistance for loft conversion floors, allowing existing ceilings to be retained while meeting Building Regulations for habitable loft space.

Knauf Rocksilk Fire Resistant Insulation

Knauf Rocksilk is a range of rock mineral wool slabs, all Euroclass A1 rated and manufactured with ECOSE Technology. Five density grades are stocked, from RS45 through to RS140, covering general building applications through to high-specification commercial acoustic and fire requirements. RS45 and RS60 are the most commonly used grades for walls, partitions, and floors. RS80, RS100, and RS140 serve progressively more demanding acoustic and fire specifications. All grades are available in thicknesses from 25mm to 100mm in 1200 x 600mm slabs.

Superglass Fire Resistant Insulation

Superglass Multi Roll 44 is a glass mineral wool loft roll available in 100mm, 150mm, 170mm, and 200mm for loft insulation applications where both thermal performance and fire resistance are required. Superglass Superwall 32 is a full-fill cavity wall batt (lambda 0.032 W/mK) for masonry cavity wall construction, available in 100mm and 150mm widths. It combines non-combustible fire resistance with strong thermal performance, making it an efficient choice where both are required.

Tekfon Class 0 Fire and Acoustic Foam

Tekfon Class 0 Black Fire and Acoustic Foam meets Class 0 per Building Regulations paragraph A13(b) and Class 1 surface spread of flame per BS476 Part 7. It is not classified as non-combustible but is fire resistant and is used primarily in HVAC installations, commercial interiors, studios, marine environments, and van conversions where Class 0 fire performance alongside acoustic absorption is required. Available in 20mm and 25mm thickness.

Shop Fire Resistant Insulation by Application

Walls and Partitions

Stone wool slabs friction-fit between timber and metal studs for party walls, separating walls, and internal partitions. Rockwool RWA45 and Knauf Rocksilk RS45 or RS60 are the standard specification for combined fire and acoustic performance in a single layer.

Loft Conversions and Floor Separations

Rockwool Flexi and Knauf Rocksilk are tested to provide 60 minutes fire resistance between joists when converting a loft into habitable space. Installed between floor joists and supported by netting, they satisfy Approved Document B requirements while retaining existing ceiling linings.

Cavity Walls

Superglass Superwall 32 provides full-fill cavity wall insulation with a non-combustible mineral wool batt, meeting both fire resistance and Part L thermal performance requirements in masonry construction.

Fire Resistant Loft Insulation

Superglass Multi Roll 44 provides non-combustible glass mineral wool loft insulation in thicknesses from 100mm to 200mm, suitable for both between-joist and cross-layer loft insulation where fire resistance is required alongside thermal performance.

Why Choose Insulation UK for Fire Resistant Insulation?

A1 Rated Non-Combustible Stock All Rockwool and Knauf Rocksilk products carry the Euroclass A1 non-combustible rating, the highest classification under BS EN 13501-1.

All the Leading Brands Rockwool, Knauf, Superglass, and Tekfon all stocked at trade prices.

Competitive Trade Pricing No minimum order value on all fire resistant insulation products.

Fast UK-Wide Delivery Reliable delivery across the UK, with free shipping on orders over £500 (ex VAT).

Expert Technical Support Our team has over 50 years of experience in the insulation industry. Our priority is guidance, security, and peace of mind, ensuring your projects run as expected from idea to finished job.