Do you know what a ‘relevant building’ is? If you do, are you sure you are complying with the requirements for upstand insulation boards?

A “relevant building” is defined within Building Regulation Approved Document B as a building with a storey (not including roof-top plant areas or any storey consisting exclusively of plant rooms) at least 18 metres above ground level and which— (i) contains one or more dwellings; (ii) contains an institution; or (iii) contains a room for residential purposes (excluding any room in a hostel, hotel or boarding house); and (b) “above ground level” in relation to a storey means above ground level when measured from the lowest ground level adjoining the outside of a building to the top of the floor surface of the storey. By including institutions it also covers residential schools, care homes and hospitals, student residences or other institutional accommodation blocks.

In Scotland the 18 metre ‘rule’ changes to a storey of at least 11 metres above ground level.

Within Building Regulation Approved Document B the green highlighted (legally enforceable) section Requirement B4: External fire spread – also referred to as regulation 7, states that materials which become part of an external wall of a relevant building must be to European Classification A2-s1, d0 or A1 which is generally referred to as non-combustible. But there is an exclusion that states this requirement does not apply to ‘any part of a roof (other than any part of a roof which falls within paragraph (iv) of regulation 2(6)) if that part is connected to an external wall.  Whilst the regulation is clear that a flat roof system has to comply with the Broof(t4) requirement according to BS EN 13501-5, the exact fire requirements for the insulation used in the roof upstand where it meets the external wall is not totally clear, but as paragraph (iv) of regulation 2(6) relates to any part of the roof that is at more than 70 degrees to the horizontal roof deck and/or abuts an external wall, it can reasonably be argued that the vertical insulation on the upstand should be non-combustible.

Whilst the current consultation on regulation 7 is ongoing QI would recommend to all flat roofing contractors that they cover themselves with regards to regulatory compliance and opt to install a non-combustible insulation board on all relevant buildings, and we are here to help meet that demand.

Our range of Rockwool and Foamglas insulation board for warm roofs are non-combustible, and or RockFace A2 inverted roof insulation board is certified by Exova Warrington as achieving an A2-s1, d0 rating.

Contact QI for further information