The Habitable Room

When it comes to bedrooms, lounge rooms and generally rooms you spend time in, other than kitchens, bathrooms and laundries, there is a legal/technical term that describes same in the Building Code Of Australia called ‘Habitable Room’. In this article I’m going to discuss habitable rooms in detached houses which are Class 1 buildings.

Volume 2 of the BCA deals with Class 1 Structures..

There are several significant attributes of a habitable room that make it compliant with the BCA, three of which are:

Ceiling Height (3.8.2)
This is where the ceiling is required to be at least 2.4 metres from the floor. Technically, the floor space used to evaluate compliance allows one third of the ceiling line to be below the 2.4 meter mark, either as flat ceiling (say a raked ceiling) or as beams (ie bearers that sit below joists).

Natural Light (3.8.4)
Compliance for a habitable room is described as windows with a minimum light transmission area of no less than 10% of the floor area of the room, with the window open to the sky or an open area. With respect to Sky lights, aggregate of no less than 3% of the floor area.

There are also calculations for ‘borrowed light’ where an adjoining room provides light to the habitable room. Proportional area combining both windows and skylights is calculated per examples given in the part 3.8.4 of the code.

Ventilation (3.8.5)
This is described as an opening such as a door, window, or other device which provides a ventilating area not less than 5% of the floor area of the habitable room to be ventilated and opens to an external space such as a varandah, carport or the like, or to an adjoining room thats not a sanitary compartment and the ventilating area is not less than 5% of the total combined floor areas.

For examples and more detail see part 3.8.5.2 of the code.

You can download the entire code by registering and downloading from Here

Alternatively you can just download Volume 2 (2016) Here