Knauf Insulation launches ‘gateway-ready’ rainscreen cavity systems

By Knauf Insulation UK & Ireland
March 26, 2024

Knauf Insulation has launched Rocksilk® RainScreen Cavity Systems, a range of complete tested systems designed to simplify specification and support compliance in cladding and masonry façades. The systems consist of sheathing insulation, fixings, and cavity barriers. 

“The Building Safety Act places much more scrutiny on everyone working on high-risk buildings,” said Luke Davies, Rock Mineral Wool Product Manager at Knauf Insulation. “The ‘gateways’ it introduces, plus the ever-stricter compliance criteria of the Building Regulations, mean it’s never been more important to get your specification right. That’s why we’ve launched these systems – to make it easier for specifiers to meet these challenging requirements with a single system, backed up by rigorous test data.” 

The Rocksilk® RainScreen Cavity Systems combine existing Knauf Insulation rainscreen products with a series of new cavity barrier solutions, including open state cavity barriers with an intumescent strip, a closed state cavity barrier, and further additions to Knauf Insulation’s innovative face-fixed masonry cavity barrier range launched last year. The full range of cavity barriers enables specifiers to choose the system that best meets their fire performance needs, confident it has been tested to the relevant standards. Rocksilk® RainScreen Cavity Systems can be used with the major substrate types, including blockwork, steel, and timber. 

The full range of cavity barriers consists of: 

Rocksilk® RainScreen FireStop Slab is a cavity barrier manufactured from rock mineral wool, suitable for use as a vertical cavity barrier in buildings with a ventilated cavity, and vertically and horizontally in buildings with masonry façades.  

Rocksilk® RainScreen OSCB and OSCB Plus are horizontal cavity barriers manufactured from rock mineral wool, shrink wrapped with a reactive intumescent strip, for use in ventilated cavities up to 450mm. 

Rocksilk® RainScreen FFCB is a patented cavity barrier made from rock mineral wool, that is designed to be face-fixed to Rocksilk® RainScreen Slab as the masonry façade is constructed. It is non-combustible with the best possible Euroclass A1 reaction to fire classification and is manufactured using our unique bio-based binder, ECOSE® Technology. It is the only cavity barrier that can be fixed to the face of the sheathing insulation without needing to cut into it, which reduces waste, saves time and protects performance. 

Each cavity barrier has been tested as part of a system with Rocksilk® RainScreen Slab sheathing insulation to provide fire resistance in the appropriate rainscreen façade applications. Rocksilk® RainScreen Slab sheathing insulation is non-combustible rock mineral wool and suitable for use in higher-risk buildings, and at any height. Rocksilk® RainScreen Slab has Agrément certificates from the BBA for the broadest range of build-ups and the widest range of thicknesses of any rainscreen solution on the market. 

For more information about Knauf Insulation Rocksilk® RainScreen Cavity Systems, visit