Description
Knauf Loft Roll 44 is a glass mineral wool roll for insulating cold pitched roofs at ceiling level, and it is the most widely used loft insulation in the country. All four thicknesses share a thermal conductivity of 0.044 W/mK, so you pick the combination that gets you to the depth you need rather than trying to do it in one layer. Euroclass A1 non-combustible, rot-proof, odour free and made with ECOSE bio-based binder. In stock at our Rossendale warehouse.
Thicknesses, coverage and R-values
All rolls are 1140mm wide.
| Thickness | Coverage per roll | R-value (m²K/W) |
|---|---|---|
| 100mm | 13.89m² | 2.25 |
| 150mm | 9.18m² | 3.40 |
| 170mm | 8.01m² | 3.85 |
| 200mm | 6.84m² | 4.50 |
How much depth do I need?
Building regulations set a minimum total depth of 270mm in England and Wales, and 350mm in Scotland. New build often goes deeper again, with 400mm to 500mm common. Loft insulation is laid in two layers: the first between the joists, the second cross-laid at right angles over the top to cover the joists and stop cold bridging.
| Between joists | Cross-laid over | Total depth | Approx U-value |
|---|---|---|---|
| 100mm | 170mm | 270mm | 0.16 W/m²K |
| 100mm | 200mm | 300mm | 0.15 W/m²K |
| 150mm | 200mm | 350mm | 0.13 W/m²K |
| 200mm | 200mm | 400mm | 0.11 W/m²K |
The 100mm plus 170mm combination is the standard way of hitting 270mm exactly. U-values are indicative for a typical joisted ceiling — send us the construction and we will calculate it properly.
What does combi-cut mean?
The roll is partially perforated across its 1140mm width — two cuts at 570mm and three at 380mm. Tear it along the 570mm line for joists at 600mm centres, along the 380mm line for joists at 400mm centres, or leave it uncut and roll it out full width for the cross-laid top layer. One product covers all three situations, which is why it is the roll most installers keep on the van.
Working out how many rolls
Divide your loft area by the coverage per roll, then add around 10% for cutting and awkward corners. A 60m² loft done as 100mm between joists plus 170mm cross-laid needs roughly 5 rolls of 100mm and 8 rolls of 170mm. Tell us your loft dimensions and we will do the take-off and quote it.
Specification
- Thermal conductivity: 0.044 W/mK at all thicknesses
- Roll width: 1140mm
- Reaction to fire: Euroclass A1, non-combustible
- Glass mineral wool with ECOSE Technology bio-based binder
- Rot-proof, odour free and non-hygroscopic — does not support fungal or bacterial growth or attract rodents
- Suitable for cold pitched roofs at ceiling level and suspended timber floors
Modern manufacturing means Loft Roll 44 is classed as low itch, but it is still worth wearing gloves, a mask and long sleeves. Use a crawl board when working in a loft, and do not cover downlighters, extract fans or block eaves ventilation.
Buying from Pinks
Pallet quantities available at trade prices — ask us for a pallet rate rather than buying by the roll if you are doing a whole house or several. Next-day delivery across most of the UK, or collect from our trade counter in Crawshawbooth, Rossendale. We also stock loft boarding, eaves vents, DPM and everything else the job needs.





