In short: A heating unit platform needed support, and someone reached for whatever was on site. Lock-up was the last chance to see it.
A platform that needed holding up
Ducted heating units in Officer homes usually sit on a platform in the roof space. On one Officer build at lock-up, wedges had been hammered under several trusses to carry that platform, over an internal wall that was not designed to take any load. The wall below had become a support by accident.
Offcuts doing a structural job
Elsewhere in the same roof, fibre cement sheet offcuts had been used as packers under a steel beam and under trusses. Sheet materials like this are made for linings and wet areas. They are not rated to carry concentrated loads and can crush or crack over time, letting the member above settle.
Top plates on wedges too
The inspection also found top plates propped on wedges to bring them level. AS 1684 expects plates to bear fully on the studs below. A wedge gives a point contact that can shift as timber dries, which is when ceiling cracks and sticking doors start to appear.
Why the timing matters
All of this was visible only because the ceiling was not yet sheeted. A week later the plasterer would have closed it in, and none of it would show at handover. The owner sent the report to the supervisor the same day and asked for rated packing or a written engineering sign off at each point.
Written by our local inspection team from work carried out in Officer. Licensed building practitioners, Building & Plumbing Commission registration CDB-U 53425.
