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Wet Area Floor Wastes and Falls in Floor Tiles

Friday, December 01, 2017

Complaints about the above items come up regularly and many cases have been tested at NCAT, with the outcomes ranging from no defect, to the builder being ordered to remove and relay waterproofing and tiles.

As a result of yet another ‘falls in floor tiles’ exercise, for an expert report, relevant Codes and Standards were carefully assessed and the following conclusions reached:

  • 1. Floor wastes and falls in floors are two different issues. Even if a floor waste is installed, it doesn’t necessarily follow that the associated floor must fall to it.
  • 2. Floor wastes are not required in wet area rooms of Class 1 buildings unless the area contains an unenclosed shower (in which case the shower waste doubles as the floor waste).
  • 3. Wet area rooms of Class 2, 3 & part 4 buildings require floor wastes (regardless of the type of shower) only to prevent the potential for damage to other sole occupancy units or common areas in buildings.
  • 4. BCA Vol 3 and AS3500 simply treat floor wastes as fixtures and although they regulate size, they do not impose any requirement for the purposes of draining wet area floors. CP2.1(j) can be achieved with overflows to fittings.
  • 5. Both AS3740 and AS3958.1 regard the avoidance of safety issues (slip hazards) as the primary reason for building in falls to floors. Although the avoidance of safety issues is ‘informative’ advice (found in Appendix B to both the AS), AS3740 deemed-to-satisfy, Clause 3.3, refers the reader to Appendix B and AS3958.1.
  • 6. Overall, we concluded the deemed-to-satisfy for floor wastes is quite clear and arguing some alternate solution is unlikely to be productive. On the other hand, cogent arguments can be made that wet area floors without falls are compliant if the NCC does not require a floor waste (even though one may be installed).

Bruce Frizzell & Tony Ransley

From BCA 2016 Vol 2 eg applicable to Class 1.

From BCA 2016 Vol 1 eg applicable to Class 2, 3 or Class 4 part.

From the Guide to NCC 2016 eg applicable to Class 2, 3 or Class 4 part.

From BCA 2016 Vol 3 eg applicable to drainage in all building work.

AS3740 provides deemed-to-satisfy for both BCA Vol 1 & Vol 2. It advises:

Falls in floors can be expressed as slopes, degrees or percentages (sometimes with the intent of confusing).
The relationship is as shown right:
1:100 0.57 1
1:81.85 0.7 1.22


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