1964_BUILDING_(CONSTRUCTION)_REGULATIONS — Page 126

B 126

CAP. 123]

Building (Construction) Regulations

[1985 Ed.

[Subsidiary]

TABLE B

FLOORS AND LANDINGS

Minimum thickness in mm for period of

2

3

Construction and Materials

4

2 hours hours hour hour

+

Filler Joist Construction

Thickness of concrete

Concrete cover on bottom of joist

25 25

22

150 125 100 90

=

15

15

SOLID REINFORCED CONCRETE CONSTRUCTION

(including flat slab construction and floors constructed of precast inverted “U”, channel or T-sections, without a ceiling or soffit).

Thickness of concrete

150

125 100 90

Concrete cover to reinforcement

25

15 15

15

HOLLOW BLOCK FLOOR CONSTRUCTION

(including floors constructed of precast concrete units of box-section or I-section).

Aggregate thickness of incombustible material

(excluding ceiling finishes (if any))

125

90 75

65

Concrete cover to reinforcement

25

15

15

15

STRUCTURAL TIMBER CONSTRUCTION

Boards 22 mm thick on timber joists not less than

175 mm deep by 50 mm wide.

(a) Tongued and grooved boards with ceiling

of:-

(i) timber lath and plaster

Thickness of plaster

(ii) metal lath and plaster

Thickness of plaster

(iii) 2 layers of plaster-board, each

minimum thickness

(iv) 1 layer of plaster-board of minimum

thickness

(v) 1 layer of plaster-board of minimum thickness of 9.5 mm covered with gypsum plaster of minimum thickness

16

16

9.5

19

16

(b) Plain edge boarding with ceiling of:-

(i) metal lath and plaster

Thickness of plaster

16

(ii) timber lath and plaster with plaster of

minimum thickness of 16 mm. covered with sheets of plaster-board of minimum thickness

9.5