Knauf Loft Roll 44 (200mm) is a glass mineral wool loft insulation roll for insulating cold pitched roofs at ceiling level, and it can also be used between joists in suspended timber floors. As the thickest roll in the range, it is the preferred choice where maximum thermal performance is the priority. Used as a cross-laid layer over a 100mm base between the joists, it brings total depth to 300mm, comfortably beyond the 270mm depth commonly used to meet the 0.16 W/m²K roof U-value target under Part L of the Building Regulations. For a fully maximised specification, two 200mm cross-laid layers over a 100mm base reach 500mm, taking the U-value down to around 0.09 W/m²K, the level typically specified in new build to minimise heat loss over the lifetime of the building.

Thermal conductivity is 0.044 W/mK and thermal resistance is 4.50 m²K/W, giving strong thermal performance across loft applications. As a glass mineral wool, it also offers a degree of acoustic absorption, helping to soften airborne sound through the ceiling. Each roll measures 1140mm wide by 6.00m long and covers 6.84m², and carries a Euroclass A1 non-combustible reaction-to-fire classification, the best possible rating, meaning the product does not burn.

The combi-cut format means the roll is partially perforated to give widths of 2 x 570mm or 3 x 380mm, so it can be split to sit neatly between joists at standard centres or laid uncut as a full-width cross-laid layer. This reduces cutting and offcuts on site, speeding up installation and helping maintain continuous coverage with fewer gaps.

Manufactured using ECOSE® Technology, Knauf's bio-based binder, it contains no added formaldehyde or phenol, is CFC and HCFC free, and has zero ozone depletion potential. Made with up to 80% recycled glass content, it is one of the more environmentally responsible loft insulation products available. Modern manufacturing means it is classed as low itch and more pleasant to handle, though gloves and basic protection remain sensible when working with any mineral wool. Rot proof, odourless and non-hygroscopic, it will not attract rodents or support the growth of mould, fungi or bacteria, and will last for the lifetime of the building.

Install in line with the Knauf Loft Roll Installation Guide and the project specification, taking care not to block eaves ventilation. A full step-by-step walkthrough is available in the [loft insulation guide](LOFT INSULATION GUIDE LINK). Suitable for both new build and renovation work, it offers a straightforward route to maximising loft thermal performance and reducing heat loss.

Benefits

• Thermal conductivity of 0.044 W/mK: reliable, effective thermal performance for loft applications
• Thermal resistance (R-value) of 4.50 m²K/W for the 200mm roll
• Euroclass A1 non-combustible: the best possible reaction-to-fire classification, meaning the product does not burn
• Combi-cut format, partially perforated at 2 x 570mm and 3 x 380mm to suit standard joist centres
• 6.84m² coverage per roll
• The thickest roll in the range, ideal for maximising loft performance and future-proofing the specification
• Also suitable as a primary single layer between joists, or in suspended timber floors
• Manufactured with ECOSE® Technology, a bio-based binder with no added formaldehyde or phenol
• Made with up to 80% recycled glass content: CFC free, HCFC free, with zero ozone depletion potential
• Rot proof, odourless and non-hygroscopic: will not attract vermin or support mould or fungi
• Lightweight, low-itch and easy to handle on site
• BRE Green Guide rating A+

Good to know

• Thickness: 200mm; width: 2 x 570mm or 3 x 380mm; length: 6.00m; coverage: 6.84m² per roll
• Thermal resistance: 4.50 m²K/W; vapour resistivity: 5.00 MNs/g.m
• Packs per pallet: 24; pallet product code: 715820
• 100mm base plus a 200mm cross-laid layer gives 300mm total, for a U-value of approximately 0.14 W/m²K, beyond the 270mm Part L standard
• 100mm base plus two 200mm cross-laid layers gives 500mm total, for a U-value of approximately 0.09 W/m²K, the level typically specified in new build
• Keep insulation clear of downlights and other heat-producing fixtures, using non-combustible covers where required
• Store indoors, dry and flat; protect from prolonged sunlight and moisture
• Always refer to the Knauf Loft Roll Installation Guide before installation