The ‘fire performance’ of a roof construction is determined using either BS476-3 or test 4 method as described in CEN TS 1187 and classified according to BS EN 13501-5.


When tested in accordance with the above, the most commonly specified combinations of deck, insulation and mechanically fixed exposed Sika-Trocal membrane will normally achieve an FAA or FAB rating. Cold deck timber roof constructions with mechanically fixed exposed Sika-Trocal membrane will normally achieve an FAB rating WITH BS476 or a Broof (test 4) classification according to BSEN 13501-5. Ballasted gravel/paved membranes are generally deemed to achieve an FAA rating.


The Building Regulations define the acceptable areas of use for roofs with various fire ratings by means of type of building, size and distance from the site boundary. Ratings AA, AB and AC have unrestricted use.