BCA 12 – United Buildings Under BCA Part A42016-10-31T13:29:04+00:00


United Buildings under BCA Part A4

AUST  Hendry building surveying consultants advise that the Building Code of Australia (BCA) in Part A4 United Buildings sets out the criteria for when two or more buildings adjoining each other can be considered to form one united building. There are significant advantages to building owners when uniting of building occurs due to the acceptance under the BCA, such as allowing coverage from services to be combined and the potential delivery of cost savings through the alignment of maintenance frequencies (subject to the appropriate approvals being in place).

A4.1 When buildings are united Two or more buildings adjoining each other form one united building if they—

(a) are connected through openings in the walls dividing them; and
(b) together comply with all the requirements of the BCA as though they are a single building.

The intent of the BCA is to allow two or more buildings that abut each other to be connected (united buildings) by openings in the adjoining walls which allows an occupancy or use to extend through more than one building. The united buildings must then comply with all the requirements of the BCA under a building approval as if they were a single building and the building is then called a united building. This clause only applies to buildings that adjoin each other that can be united buildings. Buildings that are not adjoining cannot be united by means of bridges, covered walk ways, tunnels, and the like.

Clause A4.2 states that, if alterations are carried out that the result in the sealing of openings in the dividing walls, such that the buildings are no longer connected, then each separate building must be brought into compliance with the BCA as a single building.

The BCA does not require fire doors to be provided to the openings between united buildings if the floor area limitations of Clause C2.2 are not exceeded. For the purpose of this clause, there is no limit to the size of openings between the adjoining buildings, and the abutting external walls can be considered as internal walls of a single building. If the floor area limitations are exceeded when assessing the united buildings, then the openings may need to be protected by fire doors and the subject walls considered to be fire walls under the BCA.

Where united buildings involve different BCA classification, the requirement for separation of these classifications in accordance with C2.8 and C2.9 of the BCA would still apply i.e. fire doors and fire walls between adjoining buildings will need to be provided if forming the boundary between separate classifications under the BCA.

Building owners and designers should consult with a registered building surveyor before applying for a building approval, building permit or construction certificate, in order to ensure that both parties are aware of the full implications of united buildings, with respect to the BCA.

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