Knauf Earthwool RWA45

  • A versatile, multi-application product
  • Excellent thermal & acoustic properties
  • Resilient and non-combustible
  • Available in 600mm widths only
  • Choice of thicknesses
  • Rot proof, odourless & non-hygroscopic

Product Details

Rockwool RWA45 resin bonded building slabs are primarily designed for the thermal insulation of floors, walls, and roofs. Their structural properties make them easy to cut and fix between timber rafters and floor joists They do also have other constructional benefits including acoustic insulation and fire restrictive properties for partitions and ceilings.

At Southern Timber we stock the RWA45 in 50mm, 75mm and 100mm sizes but other thicknesses are available to special order.  The standard unfaced slabs are manufactured to 1200mm x 600mm. Also available to special order the aluminium foil faced and tissue faced slabs are manufactured in sizes 1000 x 600mm.

50mm Building Slab RWA45      1200mm x 600mm, 10 slabs coverage 6.48 square metres

75mm Building Slab RWA45      1200mm x 600mm, 6 slabs coverage 4.32 square metres

100mm Building Slab RWA45    1200mm x 600mm, 5 slabs coverage 2.88 square metres

Both England and Wales have regulations that govern the sound insulation between the internal walls of bedrooms and WCs with other rooms. This applies to new walls built in dwellings formed by a material change of use and new build extensions of existing dwellings.  Rockwool stone wool products reduce noise by impeding the transmission of sound through its structure or by the absorption of sound at the surface. The structure of the fibres in Rockwool RWA45 slabs makes them ideal for use as a sound absorber

Generally fire performance of partitions will be determined in line with the appropriate Building Regulations. In certain buildings there may be specific fire performance requirements for partitions separating specific room types. All Rockwool RW slab products, either un-faced or with an aluminium foil or glass fleece on one or both surfaces, achieve an A1 classification in accordance with BS EN 13501-1 and therefore comply with the requirements of non-combustible materials/products as defined in all UK and Ireland Building Regulations.  Rockwool products also help to improve the fire rating of a partition by limiting the transfer of heat across the cavity.

Rockwool RWA45 slabs are light and easily cut with a sharp knife. Shrink wrapped in polyethylene they require no maintenance after installation. Made from a renewable and plentiful naturally occurring resource, Rockwool’s design utilises trapped air for its thermal properties. Rockwool is approximately 97% recyclable.

A Material Safety Data Sheet can be downloaded from here

In summary Rockwool RWA45 slabs have beneficial thermal insulation, acoustic and fire-restricting qualities.  They are easy to handle and install, highly water repellent and non-hygroscopic.




Phone to order

01803 813 803

Lines open 7:30 - 17:00 Mon - Fri

Delivery details

Usually within 21-34 days