Superglass Multi-Roll 44

is a non-combustible glass mineral wool roll made for insulating cold lofts at ceiling level. It is laid between timber ceiling joists and then across the joists as a second layer, reducing heat loss through the roof while limiting the thermal bridging created by the timber.

The roll is partially perforated, allowing it to be divided into narrower sections for common joist spacings or left at full width for the upper layer. This reduces cutting, speeds up installation and makes better use of each roll. Superglass Multi-Roll 44 has a declared thermal conductivity of 0.044 W/mK and a Euroclass A1 reaction-to-fire classification. Superglass also states that the product is manufactured using up to 84% recycled glass.

Product Information

Superglass confirms the thermal conductivity, Euroclass A1 fire rating, loft application and CCPI assessment. The current manufacturer and specification sources also record nominal vapour resistivity and recycled-glass content.

Sizes, Pack Coverage and Thermal Resistance

R-values are calculated from thickness divided by the declared thermal conductivity of 0.044 W/mK.

Key Features

• Made specifically for insulation between and over timber ceiling joists
• Partially perforated to reduce measuring and cutting
• Can be installed at full width across the top of the joists
• Declared thermal conductivity of 0.044 W/mK
• Euroclass A1 non-combustible
• Lightweight and easier to handle than rigid insulation boards
• Flexible fibres fit around small irregularities in the timber
• Made using up to 84% recycled glass
• Useful for new loft insulation and topping up older insulation

Which Thickness Should I Choose?

100mm

Normally used as the first layer between ceiling joists where the joist depth allows it. It can also be used as part of a multi-layer build-up.

150mm

A useful upper layer where the first layer is already in place and another 150mm is required across the joists.

170mm

Commonly chosen as a cross-laid top layer over 100mm insulation to create an overall depth of approximately 270mm.

200mm

The deepest option on this listing. It is useful where a substantial top-up is needed and there is enough room above the joists without restricting eaves ventilation or access.

The correct total insulation depth should come from the project specification or thermal calculation. The roll thickness alone does not represent the U-value of the completed ceiling.

Common Uses

• New cold-loft insulation
• Topping up existing loft insulation
• Insulation between timber ceiling joists
• Cross-laid insulation above timber joists
• Cold pitched roofs insulated at ceiling level
• Domestic refurbishment and extension projects
• New-build loft floors

This product is primarily a loft insulation roll. For internal stud walls, separating floors or soundproofing systems, use an acoustic partition roll or mineral wool slab designed for those applications.

Installation Guidance

1. Check that the loft floor is dry and that any existing insulation is clean and in usable condition.
2. Remove stored items and identify cables, pipework, water tanks, downlights and ventilation openings before starting.
3. Allow the compressed roll to expand after opening.
4. Fit the first layer between the ceiling joists without forcing or compressing the insulation.
5. Lay the second layer at right angles across the joists to reduce heat loss through the timber.
6. Butt adjoining rolls together without leaving open gaps.
7. Keep the insulation clear of eaves ventilation routes.
8. Follow the light manufacturer’s clearance instructions around recessed downlights, transformers and heat-producing fittings.
9. Use raised loft legs or a purpose-made raised deck if the area will be boarded for storage.
10. Do not place standard loft boards directly on top of the insulation, as this compresses the roll and reduces its effectiveness.

Tips and Tricks

• Measure the actual loft floor area, not the outside roof dimensions.
• Deduct large openings but allow approximately 5% extra for cuts and awkward sections.
• A 100mm layer between joists followed by a deeper cross-laid roll is usually easier to fit neatly than forcing one thick roll into the joist space.
• Cut mineral wool using a long insulation knife against a straight board.
• Compress the roll only while making the cut; allow the insulation to recover before installation.
• Insulate and draught-seal the loft hatch rather than leaving it as a weak point.
• Keep cold-water tanks and pipework correctly insulated where the loft becomes colder after the ceiling insulation is upgraded.
• Do not block soffit, tile or eaves ventilation.

Common Mistakes to Avoid

• Compressing the insulation beneath ordinary loft boards
• Blocking the ventilation path at the eaves
• Leaving gaps between rolls
• Fitting 150mm, 170mm or 200mm insulation into a 100mm joist space
• Covering recessed lights without checking their insulation-clearance requirements
• Assuming the loft hatch does not need insulation or draught sealing
• Using Multi-Roll 44 as a substitute for acoustic partition roll in walls
• Walking directly on plasterboard ceilings between the joists

Frequently Asked Questions

Is Superglass Multi-Roll 44 sold by the roll or by the pack?

Each pack contains one compressed roll. The length and coverage change according to the selected thickness.

Can I lay it over existing loft insulation?

Yes, provided the existing insulation is dry, clean and not severely compressed or damaged. Lay the new layer across the joists where possible.

Can the roll be divided to fit between joists?

Yes. It is partially perforated so it can be split for common joist widths or retained at full width for laying over the joists.

Can I compress 170mm insulation into a 100mm space?

No. Use insulation matching the available joist depth and add the remaining insulation as a cross-laid layer above the joists.

Is it non-combustible?

Yes. Superglass Multi-Roll 44 has a Euroclass A1 reaction-to-fire classification.

Can I board over it for loft storage?

Yes, but the storage deck must be raised so the insulation retains its full thickness. Use suitable loft legs or a raised structural deck.

Can I use it in internal walls?

Multi-Roll 44 is made for cold lofts. For internal walls, use a product such as Isover APR 1200, Knauf Acoustic Roll, ROCKWOOL RWA45 or ROCKWOOL RW3, depending on the wall specification.

Does it improve sound insulation?

Glass mineral wool absorbs sound within a cavity, but Multi-Roll 44 is primarily sold as thermal loft insulation. For a ceiling soundproofing system, use an acoustic-grade mineral wool product with resilient bars or acoustic clips, acoustic plasterboard and acoustic sealant.

How many rolls do I need?

Divide the loft area by the coverage of the selected roll, then round up to the next complete roll.

Example for a 50m² loft using 170mm:

50m² ÷ 6.728m² = 7.43 rolls

You would need 8 rolls.

For a Standard Loft Insulation Project

• Insulation Knife – for clean cuts around joists and roof timbers
• Loft Legs – raises the storage deck without compressing the insulation
• OSB3 or Flooring-Grade Chipboard – creates the raised storage deck
• Vapour Control Layer – where required by the ceiling construction
• Expanding Insulation Foam – for appropriate gaps around rigid details, not between the mineral wool rolls
• Protective Gloves, Dust Masks and Disposable Coveralls
• Acoustic Sealant – useful for draught sealing around the loft hatch and appropriate ceiling perimeters

For a Ceiling Being Rebuilt or Soundproofed

• ROCKWOOL RW3, RWA45 or Knauf RS60 – use instead of loft roll where the ceiling specification requires a denser acoustic slab
• Furring Channel 2.4m
• Resilient Bars
• GenieClip RST or MuteClip systems
• 15mm Acoustic Plasterboard
• 19mm Knauf Plank
• SPK15 boards
• Tecsound acoustic membrane
• Acoustic Sealant
• Drywall Screws and Appropriate Fixings

Similar Products and Alternatives

Knauf Loft Roll 44

A close alternative with the same declared thermal conductivity of 0.044 W/mK. Its combi-cut design is useful for common joist centres.

Isover Spacesaver Loft Roll

A well-known glass mineral wool loft roll available in several thicknesses for between-joist and cross-laid installation.

URSA 10 Diverso Loft Roll

Another lightweight loft roll that can be divided for common timber joist spacings.

ODE Lunaflex Loft Roll Ultra 42

A slightly lower lambda product at 0.042 W/mK, giving marginally greater thermal resistance at the same thickness.

Superglass Multi-Roll 40

A lower lambda Superglass option at 0.040 W/mK, used where improved thermal performance is required within the same depth.

ROCKWOOL FLEXI

A firmer stone wool slab for fitting between timber framing. It is more appropriate where slabs are preferred or where fire and acoustic requirements influence the product choice.