Rockwool Flexi acoustic and thermal slab Rockwool Insulation

Rockwool Flexi

Acoustic and thermal flexi edge building slabs.

Dual purpose acoustic and thermal mineral wool insulation with a patented Flexi® edge along one side.

Suitable for a wide range of applications, fitting all stud and joist centers with ease.

Will not slump, even if studs shrink.

Non-combustible – Euroclass A1.

Made from diabase rock, which is a renewable and plentiful natural resource.

Does not contain gases that have ozone depletion potential (ODP) or global warming potential (GWP).

Thicknesses and Availability:

This Rockwool Range includes the following readily available product thicknesses: 50mm, 60mm, 70mm, 90mm, 100mm, 140mm, and 180mm (some thicknesses may only be available in pallet quantities as they will need to be sourced from the manufacturer before being delivered to site).

The following thicknesses are manufactured to order and have minimum order requirements: 120mm (minimum order: 16 x pallets).

Due to supply challenges from the manufacturer, please allow extended lead times on Rockwool products. In some cases, the lead times are as long as 12 weeks. Please feel free to contact me to check availability and lead times.

Product Information

General information about Rockwool Flexi

Product Application

Thermal and Acoustic flexi edge Building Slab

Rockwools versatile flexi edge building slab, Rockwool Flexi, is suitable for use in pitched roof rafters, framed external walls, internal partitions, intermediate floors, separating walls and floors, and timber suspended ground floors.

Product Make-up


Durable non-combustable stone wool spun from volcanic rock, resin bonded into slabs with a unique flexible edge along one side.

Product Properties

Thickness 50mm to 140mm
Slab Length 1.2m
Slab Width 0.4m and 0.6m
Slab Edge Square

Product Prices

Buy Rockwool Flexi

Product ex-VAT inc-VAT
Rockwool Flexi 50mm, 24 x (12 x 0.4x1.2m) = 138.24m² £615.33 £738.39
Rockwool Flexi 50mm, 12 x 0.6x1.2m = 8.64m² £38.46 £46.15
Rockwool Flexi 100mm, 30 x (6 x 0.4x1.2m) = 86.4m² £761.48 £913.77
Rockwool Flexi 100mm, 6 x 0.6x1.2m = 4.32m² £38.08 £45.69
Rockwool Flexi 140mm, 24 x (4 x 0.4x1.2m) = 46.08m² £569.80 £683.76
Rockwool Flexi 140mm, 4 x 0.6x1.2m = 2.88m² £35.62 £42.74

Limited stock of the most popular thicknesses are held at most of our depots. Where we need to bring stock in from the manufacturer, please allow up to 2 weeks for delivery

  • Generally 1 or 3 working days for delivery
  • Generally 1 to 5 working days for delivery
  • Generally 5 to 10 working days for delivery
  • Special request or made to order item, allow extended lead times. Minimum order levels may apply.
  • Please call to check availability and approximate lead times

Product availability depends upon stock levels at closest depot and delivery logistics to geographic locations

Product Performance and Guides

Product Performance, Manufacturer Downloads, and Installation Guides

Product Performance

Thermal Conductivity 0.038 - 0.035 W/mK
Fire Performance Classification A1 BS EN 13501-1
Surface Spread of Flame Non-combustable
Nominal Density approx. 33 kg/m³
Vapour Resistance Negligable
Product Thickness Thermal Resistance kg/m³ kg/m²
Flexi 50mm 50mm 1.32 m²K/W 33 kg/m³ 1.65 kg/m²
Flexi 60mm 60mm 1.58 m²K/W 33 kg/m³ 1.98 kg/m²
Flexi 70mm 70mm 1.84 m²K/W 33 kg/m³ 2.31 kg/m²
Flexi 90mm 90mm 2.37 m²K/W 33 kg/m³ 2.97 kg/m²
Flexi 100mm 100mm 2.63 m²K/W 33 kg/m³ 3.30 kg/m²
Flexi 120mm 120mm 3.16 m²K/W 33 kg/m³ 3.96 kg/m²
Flexi 140mm 140mm 4.00 m²K/W 33 kg/m³ 4.62 kg/m²

Product Certificates

Please visit the Rockwool website for product certificates.