Building Height is usually a key consideration in the planning process to achieve consistency with existing development and meet the expectation of the community.
All Queensland Sustainable Planning Act compliant planning schemes define building height as:
(a) in metres, the vertical distance between the ground level and the highest point of the building roof (apex) or parapet at any point, but not including load-bearing antenna, aerial, chimney, flagpole or the like;
(b) in storeys, the number of storeys above ground level; or
(c) in both metres and storeys, both (a) and (b) apply.
A storey is also defined as :
A space that is situated between one floor level and the floor level next above, or if there is no floor above, the ceiling or roof above, but not a space that contains only:
(a) a lift shaft, stairway or meter room
(b) a bathroom, shower room, laundry, water closet, or other sanitary compartment
(c) a combination of the above.
A mezzanine is a storey.
A roofed structure on or part of a rooftop that does not solely accommodate building plant and equipment is a storey.
A basement is not a storey.
A basement is defined as:
A space that is situated between one floor level and the floor level next below where no part of the space projects more than one metre above ground level.
Ground level is defined as:
The level of the natural ground, or, where the level of the natural has been lawfully changed, the level as lawfully changed.
When the criteria is expressed in Storeys, the onus is not necessarily seeking a consistent building height but rather a consistent density and in contrast, when expressed in metres, the actual height is the focus over the density and number of storeys.
In circumstances where building height need to be tightly regulated a combination of metres and storeys is prescribed so that both requirements must be met and therefore not providing any room for interpretation or flexibility.
The Take Away...
Building height can be prescribed in several ways depending on the desired outcomes sought for the neighbourhood or zone. Height will be prescribed in metres if overall height is more important that density. Storeys will be prescribed if density is the key consideration over overall building height. Prescribing one and not the other allows for design flexibility but if both are prescribed, design flexibility is limited as both aspects need to be controlled due to the setting and sensitivity to building height and density. It is important to note the grammar used in prescribing building height as 'AND' or 'OR' will have different requirements.