When and Where Do You Need a Floor Waste Drain?

Australian building regulations, including the National Construction Code (NCC), require appropriate measures to contain water from accidental overflows from sanitary fixtures where such overflows could damage adjoining properties or areas. This is particularly relevant in wet areas like kitchens, bathrooms, laundries, and other spaces with plumbing fixtures.

To create a containment area with a floor waste drain, the floor surface should be impervious (e.g., tiled or vinyl) and waterproofed in accordance with AS 3740: Waterproofing of wet areas within residential buildings. The waterproofing membrane should be continuous and extend to junctions with walls or to a minimum distance from sanitary fixtures, typically covering all areas liable to water exposure.

A floor waste drain allows surface water from an accidental overflow to be drained effectively. For example, in an open-plan kitchen/living area, where the kitchen floor may be tiled but adjoining living spaces are carpeted, a floor waste should be located within the impervious floor zone near the sink or other fixtures that might overflow.

The floor waste assembly typically includes a graded floor to direct water to the drain, a trap to prevent sewer gases from entering the room, and a grate flush with the finished floor surface. Junction fittings may be used to integrate multiple waste lines into a single drainage system.

For multi-storey buildings or apartments, compact gully systems (such as those similar to Allproof’s Boss Gully) can be installed within limited ceiling or floor cavity space to connect shower wastes and sink outlets efficiently.

In areas with limited joist depth, such as residential renovations, shallow floor wastes like the Easy Clean Revolver system can be installed where passive fire protection is not required. However, where space allows, a traditional floor waste with a trap is preferred for ease of maintenance.

Laundry areas are also subject to these requirements under the NCC and relevant plumbing codes, even if no sink is installed, as appliances may also present overflow risks.

Maintenance considerations: Floor wastes should be located in accessible positions to allow regular cleaning and trap priming. Without proper maintenance, traps can dry out, allowing foul odors to enter occupied spaces unless dry floor wastes with external discharge (compliant with NCC and AS/NZS 3500) are used.

Australian manufacturers, including Allproof, provide a wide range of floor waste systems with discreet designs and customizable finishes to meet both functional and aesthetic requirements while complying with Australian standards and codes.