Every cross-wall shall comply with the following requirements-

a) it shall be built art an angle of not less than 40 degrees with the wall which it intersects;

b) it shall be carried up to the full-storey height of the wall which it supports;

c) if a gable is to be supported laterally by a cross-wall, the wall may be raked up to the gable in form of a buttress commencing from the top or wall-plate of the wall:

Provided that-

i) the angle of the rake is not greater than 45 degrees to the horizontal; and

ii) the height of the buttress shall be designed to provide maximum necessary support to the gable at a point where the cross wall meets the gable-face; and

iii) the cross-wall and the buttress shall be bonded to the gable.

d) Its over-all thickness shall not be less than 200 millimetres for solid walls or 280 millimetres for cavity walls:

Provided that, in a single-storey building or the topmost storey of a building, the overall thickness may be 100 millimetres for solid walls or 200 millimetres for cavity-walls;

e) the unbroken length of the cross-wall, adjoining the supported wall, shall be not less than-

i) for cross-walls less than 200 millimetres in thickness, one-third of the height of the walls; and

ii) for cross-walls not less than 200 millimetres in thickness, one-quarter of the height of the walls;

f) the length of cross-walls which are wing-walls or portions of intersecting walls shall be measured from the nearer face of the supported wall, excluding the thickness of the latter;

g) where a cross-wall is bonded into two return walls, extending in opposite directions from the two ends of the cross-wall, the length of the cross-wall, the length of the cross-wall shall include the thickness of the two return walls;

h) a cross-wall shall be deemed to be properly bonded to a cavity-wall if it is bonded to one leaf only;

i) a cross-wall which is a cavity-wall shall have both leaves bonded to the wall which it supports;

j) when a wall and the cross-wall supporting it are built up separately-

(i) the wall and cross-wall shall be bonded together by regular and evenly spaced toothings comprising half the height of the walls, so as to provided a bond of not less than 100 millimetres; or

(ii) mental anchors of minimum cross-section 3 x 32 millimetres or of equivalent cross-sectional area and at least 450 millimetres in length, with ends bent up at least 50 millimetres, shall be provided at vertical intervals not

exceeding one metre, and such anchors shall be protected against corrosion.