Uncapped and Damaged Slab Pipe Penetrations

The condensate overflow pipe from the air conditioning unit is discharging at or near the building perimeter rather than into a drain or away from the structure. Persistent moisture against the slab or wall base creates conducive conditions for termite ingress and can accelerate mortar deterioration over time.

The TPR (temperature pressure relief) or overflow pipe from the hot water system discharges near the building perimeter rather than into a dedicated drain, directing water against the slab edge and creating sustained moisture - a recognised conducive condition for subterranean termites. AS/NZS 3500.4 requires relief valve discharge to be piped to a safe, visible location away from the structure.

I traced the potable water pipework and found dissimilar metals joined directly - most often copper connected to older galvanised steel with no dielectric break. Reference: AS/NZS 3500.1. In my experience the galvanic cell at the junction accelerates corrosion, narrowing the bore, discolouring the water, and eventually causing pinhole leaks. I see this most on partial re-pipes over an older galvanised system.

I identified grey polybutylene pipework in the dwelling, installed during the late 1970s to mid-1990s window. The product was the subject of successive Plumbing Code advisories following widespread failures at acetal junction fittings. In my experience the risk of sudden splits and connection blow-outs rises sharply past 20 years of service, and I know insurers routinely flag or exclude cover on homes still running the system.

I investigated a sewage odour reported after rain and traced a downpipe, surface drain, or sub-soil line into the sanitary sewer - an illegal cross-connection. Reference: AS/NZS 3500.3. In heavy rain the extra hydraulic load surcharges the sewer main, and in my experience sewage can back up into the house through floor wastes and gully traps. Owners also face penalties from the water authority.

I followed the temperature and pressure relief valve discharge line from the storage hot water unit and it does not match the reference requirements I work from in AS/NZS 3500.4. I commonly record over-long runs, no visible air gap at the termination, upward runs that trap water, or the line terminating inside a cupboard or roof space. A failed discharge path stops the valve venting safely if it sticks - a scald and pressure hazard in my view.