Guidance for the Use of Building Boards with A1 or A2 Reaction to Fire Classifications in Flat Roofing

FOLLOWING an industry consultation period and with the approval of the working group, SPRA is pleased to announce the publication of a new joint SPRA-LRWA-NFRC technical guidance document, titled Guidance for the Use of Building Boards with A1 or A2 Reaction to Fire Classifications in Flat Roofing.

Within the flat roofing industry, there is a growing demand for products with A1 or A2 reaction to fire classifications (formerly referred to as non-combustible and of limited combustibility, respectively) to be used as alternatives to OSB3 and plywood.

This is due to the apparent drive of Approved Document B towards the increased use of less combustible flat roof decks and the fluctuation in prices and supply of building materials.

It has resulted in an increasing number of enquiries to SPRA, LRWA, NFRC, and their members about the use of such products in flat roofing applications. Some of the materials being considered, however, do not have relevant third-party approvals.

Building Boards Guidance

With the input of relevant manufacturers and suppliers, the document offers guidance for the use of:

• Calcium Silicate
• Cement-Bonded Particleboard
• Fibre Cement
• Gypsum (mat-reinforced)
• Magnesium Oxide building boards

The guidance is for these materials when used as:

• structural flat roof decks
• structural abutment wall upstands (including parapets)
• acoustic mass layers
• thermal barriers
• cover boards, and/or recovery boards in flat roof overlays.

The document, along with many SPRA Technical Guidance documents, is available via the SPRA website.

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