1985 Ed.]
Building (Construction) Regulations
[CAP. 123
B 129
[Subsidiary]
TABLE D
REINFORCED CONCRETE COLUMNS AND BEAMS
Construction and Materials
Minimum overall size of column in mm for period of 4 hours 3 hours 2 hours 1 hour Reinforced concrete columns 450 300 225 Reinforced concrete columns with light 50 mm mesh reinforcement in the concrete cover to longitudinal reinforcement 300 225 Reinforced concrete beams Where the minimum thickness of concrete cover to: main reinforcement specified in this Table exceeds that required by regulation 115 the excess cover may be provided by renderings of cement plaster, cement-lime plaster or gypsum plaster, on a mesh reinforcement fixed to the concrete of the beam. Minimum concrete cover to longitudinal reinforcement in columns in mm for period of 4 hours 2 hours 1 hour 65 50 25 25 Minimum concrete cover to main reinforcement in mm for period of 4 hours 2 hours 1 hour 65 50 25 15TABLE E
STAIRS
Construction and Materials
Minimum thickness in mm for period of 4 hours 2 hours 1 hour 1. Reinforced concrete construction- (i) minimum thickness at waist of slab 100 100 75 65 (ii) concrete cover to reinforcement 65 65 15 15 2. Structural timber construction (timber with all joints in treads, risers and flooring, tongued and grooved or cross tongued)— (i) Soffit unprotected Minimum finished solid thickness in any part... (ii) Soffit protected with (a) plaster not less than 16 mm in thickness on metal lathing, or (b) sheets of incombustible material not less than 5 mm in thickness on backing of close jointed boarding not less than 12 mm in thickness, or (c) sheets of incombustible material not less than 5 mm in thickness bedded to plaster and fixed securely to the carriages and joists, minimum finished solid thickness in any part... 45 301