Cills

Cills, when posts are spaced at not over 9 ft. centre to centre, shall be not less than 4 in. x 6 in. placed on edge. If posts 14 Public Health are spaced at over 9 ft. centres but not exceeding 12 ft. 6 in., the cills shall be not less than 4 in. x 8 in. or its equivalent.