Floor wastes (FW)

Published: 19 September 2011 / NCC 2011

BCA Volume Two – Class 1 and 10 Buildings

3.8.1.10 Wet area floors states “where a floor waste is installed, the floor must be constructed so that water flows to the waste without ponding. Therefore, the BCA does not require that a floor waste is installed, it only prescribes what is required if a floor waste is installed.

Plumbing Code of Australia (PCA)

Both the current Plumbing Regulations and the soon to be adopted PCA references AS/NZS 3500.2 Sanitary plumbing and drainage. As with the BCA, AS/NZS 3500.2 does not require that a FW must be installed; it only prescribes how a FW shall be installed when it is used.

Health Regulations and Local Health Laws

The requirement for a FW in a Class 1 building is prescribed in the Health Regulations and the Local Health Laws used by local governments. These regulations are outside the jurisdiction of the NCC and only provide prescriptive “instructions” on what must be done. They do not allow for performance based solutions. Until the regulations are amended, the FW remains.

FW’s come from the era of the wall mounted cistern. These cisterns tended to leak, so an underfloor tray was needed to contain the moisture and an outlet was needed to drain the moisture out of the buildings. This frames the intended use of the FW – to drain moisture from the building. They were not intended and do not have the capacity to manage flooding incidents.

Therefore, if an overflow basin, bath and the like are installed, then there is no technical reason for continuing with the regulation to install a FW. 

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