The building defects homeowners report most, and what they mean

Water escaping a wet area

The classic is a stain on the ceiling below a bathroom, or dampness in the room next to a shower, appearing within weeks or months of a renovation. It is the single most reported defect in residential work, and the most consequential, because the water is reaching timber, plasterboard and finishes that were never meant to be wet.

Wet area waterproofing is dealt with by AS 3740 and Part 10.2 of the ABCB Housing Provisions. What you cannot tell from a photo is whether the membrane failed, was never installed correctly, or was compromised later, which is exactly why a report should record the stain and recommend investigation rather than diagnose the membrane.

Treat this one as urgent. The damage keeps growing while the leak is live, and the cost of rectification grows with it.

Balconies and decks that pond or leak

Water sitting on a balcony after rain instead of draining away, or appearing in the room below, points at the external waterproofing and the drainage. External above-ground membranes are covered by AS 4654.1 and AS 4654.2, referenced by the weatherproofing provisions of the National Construction Code.

A balcony over a habitable room is part of the building's weather envelope, so this is a structural-consequence problem rather than a finish problem, even when all you can see is a puddle. It is also one of the most common sources of dispute in apartment buildings, where the balcony may be common property.

Tiling: lippage, drummy tiles and cracked grout

Tile edges standing proud of their neighbours enough to catch a toe, tiles that sound hollow when tapped, and grout that cracks along a line are the three most reported tiling complaints. AS 3958.1 covers installation, and the state guides to standards and tolerances give the numbers that builders and inspectors actually argue over.

In a dry area this is usually a finish issue. In a wet area it can be more than that: falls going the wrong way, or tiles lifting, can turn into a water problem, which is why the same photo can be a minor complaint in a hallway and a serious one in a shower.

Cracking and movement

Stepped cracking following the mortar joints in brickwork, cracks at a slab edge, or doors and windows that stop closing square, all suggest movement. Some movement is normal settlement and some is structural, and photographs genuinely cannot reliably tell them apart.

The two things that matter are whether it is getting worse and what sits behind it. AS 2870 deals with residential slabs and footings, and the structural provisions of the Code sit above it. If there is any doubt, this is the defect type that warrants a structural engineer before anyone fills and paints over it, because cosmetic repair of a moving crack simply hides the evidence.

The ones to stop using immediately

A balustrade that moves, a barrier that a child could climb or slip through, cracked glass in a door or a low window, exposed or damaged electrical work, or any smell of gas belong in a different category to everything above. These are safety matters, not quality complaints.

Barriers and stairways sit under the safe movement provisions of the Code, glass under AS 1288, electrical work under AS/NZS 3000 and plumbing under AS/NZS 3500. But the practical advice is simpler than any of that: keep people away from it and get the relevant licensed trade to inspect it now. Nobody should be assessing gas or electrical work from a photograph, including us.