(1) The roof of every building shall have proper rain-water gutters and down-pipes constructed in either:

a) galvanized sheet steel not less than 0,55 millimetre in thickness; or

b) aluminium or aluminium alloy not less than 0,7 millimetre in thickness; or

c) copper not less than 0,7 millimetre in thickness; or

d) asbestos-cement not less than 8 millimetres in thickness for diameters up to 125 millimetres, and not less than 10 millimetres or for box gutter and fittings of corresponding; of

e) unplasticized polyvinyl chloride in accordance with the requirements of C.A.S. 156; or

f) of other approved materials:

Provided that, in the case of single-storey buildings which do not abut a street, such gutters and down-pipes may be omitted when the overhang of the eaves beyond the wall-face is not less than 500 millimetres and the surface of the ground beneath the eaves is paved for a distance of 1 metre beyond the face of the wall.

(2) Where dissimilar metals are used in gutters, down-pipes or their appurtenances, precautions shall be taken to prevent galvanic corrosion by painting with bitumen-based paint or other method approved by the local authority.

(3) Gutters shall be supported by a bracket at each joint, and, if the length of gutter between joints exceeds 1,25 metres, by an intermediate bracket between joints as well.

(4) Gutters shall have a slope of not less than 1 in 200 towards outlets.

(5) the fixing and jointing of gutters, down-pipes and appurtenances thereto shall allow for expansion and contraction caused by variations in temperature.

6) The size of a rain-water gutter shall be calculated on the basis of at least 7 square centimetres of cross-sectional area for every 5 square metres of roof area served by such gutter.

7) The size of a rain-water down-pipe shall be calculated on the basis of at least 7 square centimetres of cross-sectional area for every 7 square metres of roof area served by such down-pipe.