Question 1

1. What is RWA45 insulation?

Accepted Answer

Rockwool RWA45 is a semi-rigid stone wool insulation slab designed for thermal, fire, and acoustic insulation. Like other insulation slabs, it’s made to be fitted within stud walls, floors, ceilings, and roof spaces, and can be used for both residential and commercial buildings. The ‘45’ in the name refers to the insulation’s approximate density of 45kg/m³, which offers a balance between acoustic performance and ease of installation.

Question 2

2. What’s the difference between Rockwool RWA45 and RW3?

Accepted Answer

The main difference between RWA45 and RW3 is density. RWA45 has a density of around 45kg/m³, while RW3 is denser at roughly 60kg/m³. RW3 slabs are often specified where higher acoustic performance or more rigid slabs are needed, whereas RWA45 is a more general-purpose option, generally at a lower price point.

Question 3

3. Is RWA45 insulation good for soundproofing?

Accepted Answer

Yes, Rockwool RWA45 is designed to provide acoustic as well as thermal insulation, and is widely used for soundproofing in internal partitions, floors, and ceiling systems. Its open fibre structure helps absorb airborne sound and reduce noise transfer between rooms.

Question 4

4. How do you cut Rockwool RWA45 insulation?

Accepted Answer

RWA45 slabs can be cut using a sharp insulation knife, serrated knife, or fine-tooth saw. Mark the cut line clearly before cutting, which should be done on a stable surface. PPE such as gloves, eye protection, and a dust mask is recommended during handling and cutting.

Question 5

5. Rockwool Sound Insulation Slab vs RWA45 insulation slab: what’s the difference?

Accepted Answer

Rockwool Sound Insulation slabs and RWA45 slabs are both stone wool products designed for acoustic insulation, but they’re aimed at slightly different applications. Rockwool’s RWA45 is a more general-purpose product, offering thermal and acoustic insulation, while their Sound slabs are designed specifically for acoustic jobs.

One of the main differences is density. RWA45 has a nominal density of 45kg/m³, while Sound Insulation Slab is lighter at around 35kg/m³ and includes a flexible edge for easier friction fitting between studs and joists. Both products are non-combustible and suitable for helping meet Approved Document E requirements when installed as part of a tested system.

You can find a selection of different Rockwool sound insulation options here.

Rockwool RWA45 slabs

100mm Rockwool RWA45 Insulation Slab (2.88m²)

50mm Rockwool RWA45 Insulation Slab (6.48m²)

75mm Rockwool RWA45 Insulation Slab (4.32m²)

25mm Rockwool RWA45 Insulation Slab (11.52m²)

30mm Rockwool RWA45 Insulation Slab (8.64m²)

40mm Rockwool RWA45 Insulation Slab (8.64m²)

60mm Rockwool RWA45 Insulation Slab (5.76m²)