In short: Where two slab beams meet, extra bent bars tie them together. On a Truganina slab in July 2026 they had not been placed at any corner, and nothing else on site would have flagged it.
What an intersection bar does
A stiffened raft slab is a grid of beams. Where an edge beam meets an internal beam, the engineer details L shaped bars that lap from one into the other so the two act as one. Without them the junction relies on the mesh alone, which is not what was designed for ground that moves.
What we found
At a pre-pour inspection in Truganina on 20 July 2026, the corner L bars at the beam intersections had not been installed as the drawings required. The inspector's note was simple: all corners need to be done. It was rated a major structural item.
The other slab items that day
The same slab had loadbearing stems narrower than the 150mm needed to pass load to the footings, beams narrowed where waffle pods had shifted, mesh sagging with no bar chairs beneath it, a vapour barrier pulled over the steel, and pipe ends left open. Each was fixable before concrete.
Why it had to be that day
Once the pour goes ahead none of this can be seen again. A missing corner bar does not announce itself; if it ever matters, it shows up years later as cracking that is hard to trace to its cause.
What to ask your builder
Ask for the pre-pour date as soon as the steel fixer is booked, and for confirmation in writing, with photos, that the reported items were corrected before the truck arrived. The Guide to Standards and Tolerances 2015 and AS 2870 are what the slab items are referenced against.
Written by our local inspection team from work carried out in Truganina. Licensed building practitioners, Building & Plumbing Commission registration CDB-U 53425.
