40
Thickness
of partition walls.
Damp-proof courses to
14
21. Partition walls not exceeding twelve feet in height and the external walls of latrines, bathrooms and stair hoods not exceeding eight feet in height may be constructed of brick in cement-mortar of a thickness of four and a half inches, or of reinforced concrete or of such other material and of such thickness as the Building Authority may permit.
22. Every wall of every new building shall have a damp- be provided. proof course composed of materials impervious to moisture to be approved by the Building Authority extending throughout its whole thickness and at such level as the Building Authority may require.
Construction of founda- tions.
Retaining
walls.
Every external or enclosure wall which abuts against the earth shall be protected by a vertical damp-proof course set
in a position satisfactory to the Building Authority.
23. The foundation of every wall of a building shall be of footings of sound stone, brick, concrete, or other equally hard substance, carried down to a depth of not less than twice the thickness of the wall in the lowest storey of the said building; and the lowest course of every such foundation shall be of a width of not less than twice the thickness of the wall in the said lowest storey, and the width of such foundation shall diminish gradually towards the upper surface thereof in regular steps or offsets: Provided that on rock or hard ground of an incompressible nature, or in sandy, unstable or soft ground, the Building Authority may permit or require the foundations of all works and buildings to be of such special depth and width and of such materials as shall be approved by him as being in each particular case applicable to such ground.
24. Retaining walls shall be constructed of masonry, brickwork or cement concrete. Such walls when constructed of masonry or brickwork shall be properly bonded and built solid throughout in cement mortar or when built in masonry may be laid dry.
Every retaining wall shall be provided with one or more adequate foundation courses of cement concrete laid at right angles to the face of the wall on solid ground or piling and each course shall not be less than 12 inches in depth and shall project at least inches beyond the face of such wall and shall extend the full thickness of such wall. All masonry and brick walls exceeding 12 feet in height shall be provided with lacing or bond courses of good cement concrete at least one foot in depth extending throughout the full thickness of the wall. The lacing courses shall be thoroughly keyed into the wall on their upper and lower beds. The distance between the top of the foundation courses and first of such lacing courses and the distance between any two adjacent lacing courses shall not exceed 6 feet measured vertically. In the case of a masonry wall the stones shall be roughly squared and have flat beds, and bond or header stones at least 2 feet 6 inches in length must be inserted in alternate courses and laid to break joint and there shall not be less than one such bond or header stone to every square yard of surface area of the wall. the back of every retaining wall (except when such is con- structed in dry masonry) there shall be formed a layer of hand-packed broken brick or granite of a thickness of at least 12 inches and every such wall shall also be provided with weepholes of not less than 3 inches internal diameter and at least one such weephole shall be provided to every four super- úcial yards of the face of the wall.
At
15.
Every retaining wall shall be provided with a proper cop- ing of cement concrete or other impervious material approved by the Building Authority and adequate channels shall be formed at the top and toe of every such wall to intercept and carry off stormwater.
The design of every retaining wall, breast wall, dam or similar structure shall be subject to the approval of the Building Authority to whom a stress diagram of the wall must be sub- mitted.
of boundary
25. No person shall construct or reconstruct any bound- Construction ary wall or enclosure wall fronting any public road or or enclosure thoroughfare unless it is solid throughout its entire thickness walls. and built of brick or stone properly bedded and bonded together, surmounted by a coping of dressed stone or properly moulded bricks set in cement mortar or constructed of such other materials as may be approved by the Building Authority.
to be carried up above
26. Every party wall shall unless exempted by the Build- Party walls ing Authority be carried up above the upper surface of the roof of every building to a height of at least eighteen inches, roof. measured at right angles to the slope of the roof, and every such party wall and every parapet wall shall be properly coped with a coping composed of cement and sand in the proportion of not less than one part of cement to every two parts of sand, or of such other material as the Building Authority may approve, or shall be otherwise protected in order to prevent water soaking into such wall,
27.-(1) Openings may only be made in party walls to Openings an extent not exceeding one half of their area on each storey party or through unless in the opinion of the Building Authority a greater area external may be allowed.
(2) When it is desired to close any openings previously made through any party wall, such openings shall be solidly stopped up with brick or stone-work of the full thickness of the party wall, and such brick or stone-work shall be built in lime-mortar or cement-mortar and properly bonded with such party wall. Any future openings through any such party wall shall be restricted to the removal, in whole or in part, of such stoppings, unless the previous openings did not extend to one half of the area of such wall, and additional openings shall only be made in such manner as to ensure that the total extent of the openings, inclusive of those previously made, shall not ex- ceed one half of the area of such wall on each storey.
walls.
(3) Recesses may be made in party walls and in external Recesses, walls : Provided that the aggregate area of such recesses does not exceed one-half the whole area of the wall of the storey in which they are made, and that the backs of such recesses are of not less thickness than thirteen inches in party walls, and nine inches in external walls.
(4) In the case of a shop front left open to the street, the Returns to side walls or party walls shall be returned along such front for shop fronts. at least twelve inches where the house has more, and for al least nine inches where the house has not more, than one storey above the ground storey, and such return walls shall be properly bonded into the side walls or party walls in cement mortar. Where such shop front is in a corner building, the side wall shall be returned along such front for at least two feet.
41