Overview
A proactive inspection of multiple single and double storey Class 1 dwellings under construction identified more than 30 non-compliances in each dwelling that have the potential to impact the amenity of the dwellings if they were not rectified.
The non-compliances related to a range of poor sanitary drainage work that could have resulted in recurring blockages and water ingress. This work included an incorrectly designed stack (leading to incorrect venting) that did not achieve a minimum grade and PVC joints not constructed appropriately. This could lead to recurring leakages and blockages in the sanitary drainage system and, fixtures (e.g., showers/toilets) not operating efficiently. Stacks are commonly costly to repair as it requires the removal of waterproofing, tiles, and plaster to conduct repairs and the dwelling may become uninhabitable while works are being repaired.
Additionally, 90mm stormwater PVC was installed and used on a below ground sewer drainage system and PVC joints were not constructed correctly. This could have resulted in water leaking into and under the building's structure.
Flexible duct work for the heating and cooling system was not installed correctly, restricting airflow and connections were not applied correctly to starting collars. Condensate drains were also interconnected, compromising the fail-safe leak system.
Above ground gas piping was also found to be non-compliant. The jointing used in gas piping was not constructed in accordance with the manufacturer's instructions and gas piping was not protected from corrosion and sharp objects throughout the dwellings. Further issues were also observed in water pipes that exceeded the maximum clip spacing and were also not protected from sharp objects.
Response
A Victorian Building Authority (VBA) notification to the RBS and builder prompted the builder to notify the responsible plumber about the non-compliant work. The plumber provided the VBA with photographic evidence to demonstrate rectification of the work, however, not
all items were addressed. Due to conflicting advice received from the plumber, the VBA re-inspected the site and found the plumber had provided the VBA with photos that were not relevant to this site and most of the non-compliant matters identified had not been addressed. Further issues were also observed and added to the rectification requirements.
Further Action
Due to the volume and extent of non-compliant items at the site, the VBA plumbing inspector arranged a re-inspection with the construction company's Area Manager and Site Manager to highlight to them the poor plumbing work being produced by their contracted plumbing practitioner.
Outcome
The builder put work at the site on hold and terminated the contract with the plumbing practitioner. A new plumber was appointment who completed the rectification works and the VBA closed the matter upon reinspecting the site for a fourth time.
The findings by the VBA in this case, and actions taken to bring the plumbing work into compliance addressed real concerns for future amenity of the dwellings and protected the consumer (both current or any future owners) from the burden of non-compliant work.
A VBA inspector subsequently attended four other sites where this builder was operating and observed similar plumbing non-compliances that were also rectified by the newly appointed plumbing practitioner. The plumber in question has been flagged for further attention through the VBA plumbing audit program (PAP) which could lead to further investigation and action.
Figure 1: Discharge pipes do not have the appropriate grade contrary to AS/NZS 3500.2:2021 Table 6.6.1
Figure 2: Some risers are not installed parallel, pipe work shall be in the same alignment and grade as the preceding pipes or fittings. AS/NZS 2032:2006 Clause 4.2.3
Figure 3: Incorrect junctions and venting of the sanitary drains contract to AS/NZS 3500.2:2021 clause 9.5.2 & 9.2.2 AS/NZS 3500.2:2021 Clause 6.6.2.3
Figure 4: Gradient of drain going backwards contrary to AS 3500 2:2021.clause 3.4.1
Figure 5: 90mm PVC piping. not suitable for sanitary drainage systems contrary to AS/NZS 3500.2:2021 clause 2.5.1 and manufactures installation specifications.
Figure 6: Water pipes exceed the maximum clip spacings contrary to AS/NZS 3500.1:2021 Table 5.7.4 AS/NZS 3500.4.2021 Table 4.5.4
