(1) Where floor-slabs or other slabs or beams are supported by masonry or plain concrete walls, piers or columns, no loads other than the normal surface finishes shall be superimposed upon such supporting members, unless adequate falsework is left or placed under them to carry such superimposed loads without undue deflection, until-

a) such time as the mortar or concrete in such walls, piers or columns has attained the minimum comprehensive strength at 28 days applicable to the class of mortar or concrete employed, as specified in section 13 or 14 respectively; or

b) failing tests to demonstrate such strength referred to in paragraph (a), the following periods have elapsed after the mixing of the mortar or concrete used in the last portion of such walls, piers or columns to the constructed-

i) for class D mortar, 28 days;

ii) for other mortar and concrete made with-

A. Portland cement other than high early strength Portland, 28 days;

B. high early strength Portland, cement, 5 days.

TABLE II

cementitous materials

(2) Fill or back-fill shall not be placed against any wall until the period set out in Table II for the relevant maximum height of fill has elapsed after the completion of the wall.