Measuring storey and wall heights

The height of a wall or a storey should be measured in accordance with the rules in Diagram 4C.6. (a) Measuring storey heights: A is the ground storey height if the ground floor is a suspended timber floor or a structurally separate ground floor slab; A1 is the ground storey height if the ground floor is a suspended concrete floor bearing on the external wall; B is the intermediate storey height; B1 is the top storey height for walls which do not include a gable; C is the top storey height where lateral support is given to the gable at both ceiling level and along the roof slope; D is the top storey height for walls which include a gable where lateral support is given to the gable only along the roof slope. (b) Measuring wall heights: H1 is the height of a wall that does not include a gable (if the wall has a parapet see P); H2 is the height of a compartment or separating wall which includes a gable; H3 is the height of a wall (except a compartment or separating wall) which includes a gable; P if the parapet height is more than 1.2 m, add the height to H1.