(1) Empirically constructed brick foundation-walls, sleeper-walls or basement-walls shall coply with the requirements of the following subsections.

(2) The effective of such walls shall be not less than 215 millimetres, measured exclusive of skin-walls which protect damp-proof treatment.

(3) Fill placed between such walls shall not be placed before the periods set out in section 9 have elapsed after completion of such walls, and such fill shall, in opinion of the local authority, be sufficiently dry at the time of placing, and sufficiently well drained.

(4) The full height of the fill referred to in subsection(3), measured above the adjoining finished ground-level, shall not exceed the following-

a) for a wall 215 millimetres in thickness, 1,8 metres;

b) for a wall 280 millimetres in thickness, solid, 2,1 metres;

c) for a wall 330 millimetres in thickness, 2,7 metres:

Provided that the height of such fill shall not exceed one metre where the fill shall not exceed one metre except where the fill is one of hardcore or the floor is designed and constructed as a suspended floor and carried through the thickness of the supporting walls.

(5) The full height of exterioe back-filling, measured above the level of a solid floor or above the ground surface under a suspended floor, placed against such wall shall not exceed the values given in subsection (4) for fill, and the following requirements shall be complied with-

a) there shall be no surcharge above the point at which the surface of the back-filling meets such wall;

b) the back-filling shall be drained to the satisfaction of the local authority;

c) the thickness of any skin-wall which protects vertical damp-proof or waterproof layers shall not be included in the thickness of any foundation-wall or basement-wall when the permissible height of back-filling id determined