Rockwool Cavity Slab fulfill cavity insulation Rockwool Insulation

Rockwool Cavity Batt

Full fill cavity wall batts.

Excellent thermal, acoustic and fire insulation.

Suitable for new-build and renovations in masonry cavity and party wall applications.

Can be used in domestic and non-domestic buildings up to 25m high.

Prevents water transmition from outer to inner leaf.

Non-combustible – Euroclass A1.

Durable, rot-proof, water resistant and sufficiently stable to remain effective as insulation for the life of the building.

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, 75mm, 80mm and 100mm (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), 130mm (minimum order: 16 x pallets) and 150mm (minimum order: 14 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 Cavity Batts

Product Application

Thermal batt for Masonary Cavity walls

Rockwools full fill cavity slab, Rockwool Cavity, is suitable for use in masonry cavity wall construction and masonry party walls between dwellings in both new builds and extensions.

Product Make-up


Durable non-combustable stone wool spun from volcanic rock with water repellent additives which prevent moisture transmission.

Product Properties

Thickness 50mm to 130mm
Slab Length 1.2m
Slab Width 0.455m
Slab Edge Square

Product Prices

Buy Rockwool Cavity Batt

Product ex-VAT inc-VAT
Rockwool Full Fill Cavity Batt 50mm, 12 x 0.455x1.2m = 6.55m² £53.66 £64.39
Rockwool Full Fill Cavity Batt 75mm, 9 x 0.455x1.2m = 4.91m² £49.44 £59.32
Rockwool Full Fill Cavity Batt 80mm, 8 x 0.455x1.2m = 4.37m² £45.07 £54.08
Rockwool Full Fill Cavity Batt 100mm, 6 x 0.455x1.2m = 3.28m² £41.76 £50.11

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 0.037 W/mK
Fire Performance Classification A1 BS EN 13501-1
Surface Spread of Flame Non-combustable
Nominal Density 33 kg/m³
Vapour Resistance Negligable
Product Thickness Thermal Resistance kg/m²
Rockwool Cavity 50mm 50mm 1.35 m²K/W 2.25 kg/m²
Rockwool Cavity 75mm 75mm 2.03 m²K/W 3.37 kg/m²
Rockwool Cavity 80mm 80mm 2.16 m²K/W 3.59 kg/m²
Rockwool Cavity 100mm 100mm 2.70 m²K/W 4.50 kg/m²
Rockwool Cavity 150mm 150mm 4.05 m²K/W 6.75 kg/m²

Product Certificates

Please visit the Rockwool website for product certificates.