(1) In any case where the local authority is satisfied, from a knowledge of the subsoil conditions in the locality within which a proposed building is to be situated, or from experience of the behavior of buildings in such locality, that it would not endanger a proposed building to do so, it may permit the erection of such building without a site investigation in terms of section 3.

(2) Unless the local authority specifically calls for a site in terms of section 2, buildings may be erected without such an investigation in cases where-

a) the proposed building is a dwelling-house not exceeding a height of two storeys; or

b) the proposed building is a single-storey building, the supporting walls of which do not exceed 4 meters in height.

(3) Buildings falling within the description contained in subsection (2) may be built on foundations constructed in accordances with the empirical rules contained in subsections (4) to (7).

(4) Concrete foundations shall so be constructed that-

a) the foundation under sleep-piers not less than 450 millimetres either in length or in breadth, and the width of foundations under sleeper-walls shall be not less than 300 millimetres;

b) the vertical thickness of other foundations shall be-

i) not less than 200 millimetres for walls of 200-millimetre thickness and over;

ii) not less than 150 millimetres for walls of less than 200-millimetre thickness;

c) the width of foundations under walls, other than sleep-walls, shall be not less than the thickness of the wall plus twice the vertical thickness of the foundation.

(5) For the purposes of subsection (4)-

a) the thickness of the wall shall be measures just above the ground-floor level, except where the foundation wall is higher than 1,5 metres, in which case the thickness of the wall shall be measures just above the foundation; and

b) the thickness of a cavity-wall shall be regarded as the sum of the thickness of leaves of such a wall.

(6) Masonry Foundations constructed with stone, brick or solid concrete blocks shall be permitted:

Provided that the local authority may require that any such foundations be built on an approved bed of concrete.

(7) Masonry foundations shall comply with the following requirements-

a) such foundations or columns or sleeper-piers hall be permitted only on rock or on coarse sand or compact gravel;

b) the vertical thickness shall be not less than 225 millimetres and not less than twice the maximum projection from the face of the wall, column or pier being supported, whichever is the greater, exclusive of any bed of concrete which may have been provided;

c) the lateral dimensions of foundations under sleep-piers and walls shall be as given for concrete foundations in paragraph (a) of subsection (4);

d) the width of other foundations shall be-

i) for single-storey buildings, not less than the thickness of the wall plus 150 millimetres; and

ii) for double-storey dwellings, not less than twice the thickness of the wall;

e) when such a foundation is stepped is cross-section, the height of any step shall not exceed 225 millimetres and the projection of any step shall not exceed half the height of the step;

f) the mortar used shall be not weaker than class A or class B, as specified in Chapter 5.