Within the flat roofing industry, there is a growing demand for products with limited combustibility to be used as alternatives to OSB3 and plywood, due to the drive of Approved Document B towards increased uses of less combustible decks and the fluctuation in supply and prices of building materials throughout 2021. This has resulted in an increasing number of enquiries to the Single Ply Roofing Association (SPRA), Liquid Roofing and Waterproofing Association (LRWA), National Federation of Roofing Contractors (NFRC) and their members about the use of limited combustibility boards as flat roof decks; abutment/ parapet wall upstands; and acoustic mass boards, fire retardant boards and/or recovery boards in flat roof overlays.
Some of the materials being considered for use do not appear to have relevant certifications relating to their proposed use and, in some cases, LABC Warranty, NHBC Warranty and Zurich Municipal projects have advised against the use of such materials for the applications mentioned above completely.
By changing a material specification to include alternative components such as limited combustibility boards implies that the authorising party is thereby assuming design liability for the construction. There is a duty of care on the part of the ‘designer’ to ensure that any changes to the construction include the appropriate test certification and are fit for purpose.
In a cross-industry approach to this matter, SPRA, LRWA and NFRC are working with others to produce a guidance
document about the use of limited combustibility boards as flat roof decks; abutment/parapet wall upstands; and acoustic mass boards, fire retardant boards and/or recovery boards in flat roof overlays. The aim is to ensure that the correct guidance is available to its members and specifiers, thereby preventing misleading and inappropriate product claims.
As there is no current industry standard for these materials in this use, the group would expect all manufacturers of limited combustibility boards to follow the guidance set out in the incoming Code for Construction Product Information (CCPI), published in September 2021. Clause 5 states specifically that, ‘A Manufacturer must provide specific documentation when making any product performance claims which are outside of Certification, Classification or Industry Standard tests;
- All stated performance data must be referenced back to a valid dated test or specified technical assessment
- Where a test is referenced, it must state the Construction Product tested, the test, date passed, under
what standard, where tested and by whom and the last date its validity was reviewed - Stated performance data must be clear as to whether it is based on calculated and/or tested performance and manufacturers must clearly state where tests are laboratory tests;
- Specific properties relevant to intended application must be clear e.g., structural/fire/acoustic/ thermal
- Be specific to the intended application and where known, provide examples of limitations or inappropriate applications.’
Ideally, in accordance with the CCPI, the group would encourage that these products should be certified
by a third party such as BBA, KIWA etc, for the intended application(s). It is not acceptable simply to
hold third-party certification, which does not specify the intended application as set out above.
SPRA, LRWA and NFRC are requesting that manufacturers of products under consideration and their associated trade
associations join in this whole industry approach. In the meantime, prior to any change in specification, we would recommend that written clarification is sought from the appropriate authority prior to commencement of works as to what their requirements are.
This communication is issued jointly by the Single Ply Roofing Association (SPRA), Liquid Roofing and Waterproofing Association (LRWA) and National Federation of Roofing Contractors (NFRC)
