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Announcing new Steel Frame Direct-Fix accreditation

direct fix ewi onto steel frame

We’re delighted to announce that we’re now in possession of our latest approval certificate covering the direct fix application of an external wall insulation system onto a sheathed steel frame substrate

This new KIWA BDA certified system is a welcome addition to our incredible accreditation portfolio and incorporates both a silicone render finish and brick slip finish onto A1 Stone Wool insulation.

Ideal for schools, student accommodation, and high-rise re-clad projects, the system achieves an A1 fire classification to BS EN 13501-1 using a WBS brick slip finish and an A2-s1,d0 fire rating using WBS silicone render.

The system also comes with a 30 year life expectancy.

Steel Frame Direct Fix EWI - Brick Slip
Steel Frame Direct Fix EWI - Silicone Render

Technical Director, Joe Ragdale said, “Installing this system directly to the sheathing board, omitting the cavity, can significantly improve fire performance. The installation process is simplified and there is no requirement for, or reliance on, cavity closers or fire breaks behind the A1 rated WBS Stone Wool Insulation”. 

Whilst some insurers such as NHBC/LABC currently insist on the inclusion of a drainage cavity when installing an external wall insulation system onto a framed substrate; many projects do not require this cavity, and it is not a detail often favoured by Designers and Architects. This is where the Wetherby Steel Frame Direct Fix EWI system comes firmly into play.

This new agrément certificate covers a variety of sheathing boards, including plywood, OSB and CPB boards for use on low to mid-rise properties. However, A-Rated Cement Particle Boards are required on projects over 18m in height, as per building regulations. The brands of sheathing board permitted are to be approved by Wetherby before use.

A1 fire classification*
using a brick slip finish

A2-s1,d0 fire classification*
using silicone render.

*to BS EN 13501-1

To help facilitate the roll-out of this newly approved system, Wetherby’s technical team will carry out essential pre-contract investigations, such as a condensation risk analysis. The team will also ensure that all due diligence is carried out on each project regarding system suitability to ensure compliance with any other insurer and parties involved.

Of course, in instances where a cavity is still required, Wetherby’s Epsitec  BBA / KIWA certified cavity system can still be used.


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