Radmat waterproof membranes

Impact of the Fire Regulation Changes on Roofing Systems

Building Products Index Ltd Insulation, Waterproof Membranes, waterproofing Leave a Comment

View the Radmat entry on BPindex

Visit the Radmat website

_©Jon Lucas_Bloomberg_4392On 21stDecember 2018 the Government of England and Wales brought into force revisions to the Building Regulations aimed at preventing a repeat of the Grenfell Tragedy.  Unfortunately, the nature of the release of the Amendments, and the requirement for reader to insert information into the existing Building Regulation’s has led to some misinterpretation of the revised regulations (which have now been re-published in full).

What is clear is that the Government of England & Wales now require that materials which become part of an external wall, or specified attachment, are of European Classification A2-s1, d0 or A1, classified in accordance with BS EN 13501-1:2007+A1:2009 entitled “Fire classification of construction products and building elements” on high-rise buildings that contains flats, as well as hospitals, residential care premises and student accommodation above 18 metres. These products are widely referred to as ‘non-combustible’.

What is also clear is that the requirement for ‘non-combustible’ products does not extend to roofing systems as they are covered by a specific statement in regulation 7(3) Paragraph (2) does not apply to:

(b)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’.
and
(g) membranes

ProTherm Rockface build upWhere the requirement for ‘non-combustible’ materials does apply is in regulation 2(6)(a)(iv) any part of a roof pitched at an angle of more than 70 degrees to the horizontal if that part of the roof adjoins a space within the building to which persons have access, but not access only for the purpose of carrying out repairs or maintenance;.  However, there remains a requirement for clarification of this statement, which the roofing sector is currently seeking from MHCLG as flexible roof waterproofing materials are not ‘non-combustible’.  They are manufactured to meet the relevant fire test standards contained in Approved Document B section B4 (BS 476-3 and BS EN 13501-5:2005+A1). The does not apply statement in regulation 7(3)(g) membranes would seem to confirm the waterproofing does not need to be ‘non-combustible’ but the other elements of the roofing system such as deck and insulation will need to be.

A second area requiring clarification is regulation 2(6)(b)(i) a balcony attached to an external wall;.  Traditional balcony construction projects from the building, as it is were an attachment to the external wall.  But modern construction includes for ‘balcony over balcony’ construction and ‘balcony over habitable space’ construction.  It is the general belief of the roofing sector that the requirement for ‘non-combustible’ material does impact ‘balcony over balcony’ construction, but that a ‘balcony over habitable space’ construction is not affected as it is actually a flat roof due to the requirement for waterproofing and insulation and is therefore covered under Approved Document B section B4.

The last area requiring clarification is regulation 2(6)(a)(ii) any decoration or other finish applied to any external (but not internal) surface forming part of the wall;.  Whilst it is clear that a flat roof is exempt from the non-combustible requirements of the regulations there remains a question about high parapet walls as they form the internal face of the external wall.  It is the belief of the author that the ‘non-combustible’ requirements of the regulations do apply to the detailing of the roof at this point and the insulation and substrate should meet European Classification A2-s1, d0 or A1.

A point of note in closing, in Scotland the Technical Handbooks change the height of building impacted by the regulation changes to those above 11 metres.

Leave a Reply

Your email address will not be published. Required fields are marked *