ROCKWOOL launches new Steel Frame Slab insulation

Non-combustible range brings significant benefits to steel frame developers and builders.

Steel frame building/construction

ROCKWOOL has introduced a new dedicated range for off-site Steel Frame projects, including Rainscreen Façade applications.

“Light steel frame systems are increasingly important off-site technologies used in many different building types,” comments James Mills, Product Manager at ROCKWOOL. “In light of the five-year plan published by Homes England1, the government’s housing accelerator, we can see steel frame technology becoming more integral to the future of construction, in particular, housing, student accommodation and apartment living. Our new Steel Frame Slab insulation is specifically designed to support this growth. It meets thermal and acoustic insulation requirements, is quick and easy to install, sustainable, water repellent and vapour permeable. Above everything, because it is a non-combustible stone wool product, it will not burn.”   

Designed for fast, high quality external wall installation, ROCKWOOL Steel Frame Slab can meet or exceed the requirements (thermal) of Part L of the Building Regulations by delivering a thermal insulating performance of 0.034 w/mK at optimal density. It is lightweight, easy to handle and supplied in a choice of 90mm, 100mm, 120mm and 150mm thickness slabs with 600mm widths. This ensures a tight friction fit in standard frames, with no gaps, saving installation time and keeping waste to an absolute minimum. 

This new product also offers outstanding acoustic insulating performance. The dense, non-directional fibre structure of Steel Frame Slab traps sound waves and dampens vibration, reducing sources of external noise. In Rainscreen applications, it is ideal for use as an in-fill framing solution in combination with an external layer of ROCKWOOL Rainscreen Duo Slab® alongside the ROCKWOOL OSCB fire barrier to provide a complete ROCKWOOL system delivering thermal, acoustic and fire protection in Rainscreen systems

When looking at the typical noise levels produced by heavy inner city traffic (in accordance with BS 8233), ROCKWOOL acoustic tests2 show that by incorporating 100mm of RAINSCREEN Duo Slab® and the Steel Frame Slab within the in-fill, a 68 dB external noise level can be reduced by 59 dB.  The result is an internal ambient noise level as low as 9 dB, equivalent to the noise level of leaves rustling in the distance.  

As Steel Frame Slab is manufactured from stone, any waste can be collected and 97% recycled by ROCKWOOL to off-set the cost of landfill and help off-site developers enhance their sustainability credentials.

ROCKWOOL Steel Frame Slab insulation is a Euroclass A1 Fire Rated (non-combustible) product. This can help improve fire resistance both during construction and when the property is occupied.

ROCKWOOL Steel Frame Slab is designed to hold its shape for the lifetime of an installation.  This ensures that its thermal, acoustic and fire insulation performance is maintained once the property is occupied, long after the project is completed. The new range is also water repellent and vapour permeable, meaning it can breathe, allowing moisture and condensation to escape minimising damage to the fabric of the building.  


1. Homes England Strategic Plan, 2018:

2. ROCKWOOL Acoustic Performance of Rainscreen Facade Systems: