3. The height of–
(a)a building shall be taken to be the height from the surface of the ground to the underside of the ceiling of the topmost storey or, if the topmost storey has no ceiling, one-half of the height of the roof above its lowest part;
(b)a compartment shall be taken to be the height within the compartment from the upper surface of the floor of the lowest storey to the topmost ceiling or, if the topmost storey has no ceiling, the in ternal surface of the roof;
(c)a storey above the ground shall be taken to be the vertical height from the ground to the upper surface of the floor of the storey, and the expression “a storey at a height” shall be construed accordingly.