HIA - Measurements of ceiling heights (Nat)

The letters represent the following minimum dimensions:

A = 2.4m Habitable room (excluding a kitchen – 2.1m)
B = 2.4m Habitable room - two-thirds of the floor area
C = 2.1m Non -habitable room two-thirds of the floor area
D = 2.2m An attic to be habitable - two-thirds of the floor area
E = 1.5m Calculating the floor area of a room or space, any ceiling height of 1.5m is excluded
F = 2.0 Stairs (measured vertically above the nosing line)

The combined dimensions of G must not exceed one-third of the floor area (See E above) of the room or space.

For clarity, the supporting clause 3.8.2.2 of BCA Volume 2 is set out below. Subject to any planning controls that may be applied by the local council, this clause sets out the minimum ceiling heights for habitable rooms in a new dwelling.

3.8.2.2 - Ceiling heights

Ceiling heights (see Figure 3.8.2.1) must be not less than—
(a) in a habitable room excluding a kitchen – 2.4m; and
(b) in a kitchen – 2.1m; and
(c) in a corridor, passageway or the like – 2.1m; and
(d) in a bathroom, shower room, laundry, sanitary compartment, airlock, pantry, storeroom, garage, car parking area or the like — 2.1 m; and
(e) in a room or space with a sloping ceiling or projections below the ceiling line within—

i. a habitable room—

A.	in an attic — a height of not less than 2.2 m for at least two-thirds of the floor area of the room or space; and
B.	in other rooms — a height of not less than 2.4 m over two-thirds of the floor area of the room or space; and

ii. a non- habitable room— a height of not less than 2.1 m for at least two-thirds of the floor area of the room or space,
and when calculating the floor area of a room or space, any part that has a ceiling height of less than 1.5m is not included; and

(f) in a stairway — 2.0 m measured vertically above the nosing line.

Reference: Clause 3.8.2.2 and Figure 3.8.2.1 Building Code of Australia 2011 Volume Two Class 1 and 10 buildings

HIA - Measurements of ceiling heights (Nat)