TLDR: Liability for a delayed construction project almost never sits in one place. It depends on what the contract actually says about extensions of time, notice periods, and back-to-back obligations between the head contractor and the subcontractor. A head contractor can end up wearing the cost even when the subcontractor caused the holdup, simply because the paperwork wasn’t done properly at the time.
The Question Everyone Asks Too Late
Every builder has had the phone call. The tiler didn’t show up for three weeks, the concrete pour got pushed back, and now the client is asking why the handover date has slipped by a month. The instinct is to point straight at the subcontractor who dropped the ball. That instinct is usually right, but it doesn’t automatically translate into a legal outcome. Courts and adjudicators look at the contract chain, not just at who was standing on site when things went sideways.
On a typical Brisbane or Melbourne residential build, there are at least three layers of contract sitting between the homeowner and the tradesperson who actually missed the deadline. Each layer allocates risk differently, and if the head contractor hasn’t mirrored the delay provisions from the head contract down into the subcontract, gaps appear. Those gaps tend to open right where the money is.
Where the Paper Trail Falls Apart
Most delay disputes we see don’t come down to who was actually at fault on site. They come down to whether anyone wrote a letter. Standard form contracts, including the AS4000 and AS4902 suites commonly used across Australian commercial and residential projects, require formal notice of delay within a set number of days, often five or ten business days from when the cause of delay became apparent. Miss that window and the right to claim an extension of time can simply evaporate, regardless of how obviously the subcontractor was at fault.
We’ve reviewed plenty of site diaries that clearly document a plumbing subcontractor showing up ten days late. What’s missing is the formal notice that should have gone out the same week. Without it, a builder can find themselves liable to the client for liquidated damages they never actually caused, because the delay claim against the subcontractor was never properly preserved.
What “Back to Back” Actually Means in Practice
Contractors love the phrase “back to back,” meaning the subcontract terms mirror the head contract so risk flows through cleanly. In reality, back to back drafting is where a lot of subcontracts fall short. A head contract might allow 15 business days’ notice for delay events, while the subcontract underneath it only requires 5. That mismatch sounds harmless until a claim actually needs to travel up the chain and the timing doesn’t line up.
The Cost of a Generic Template
Plenty of subcontracts in use across Queensland and Victoria are still built from generic templates bought once and reused for a decade. They rarely reference the specific program of works, rarely nominate a genuine liquidated damages rate tied to the head contract, and almost never deal properly with concurrent delay, which is when both parties contributed to the same holdup at the same time. Concurrent delay is where a lot of “who’s liable” arguments actually live, and generic templates simply don’t address it.
Concurrent Delay Is the Real Battleground
If a subcontractor is running late but the head contractor also failed to give clear access to the site, most Australian courts will apportion responsibility rather than hand the whole cost to one party. This is where expert evidence, program analysis, and a properly kept site diary start to matter more than anyone expects at the start of a dispute. A well-documented critical path analysis, showing exactly which activities were on the critical path when the delay occurred, tends to decide these arguments far more than raw finger-pointing.
Why Programme Records Matter More Than Emails
We’ve seen matters where a head contractor had a folder full of frustrated emails about a subcontractor’s slow progress but no updated construction programme showing the actual critical path impact. Emails show frustration. Programmes show causation. Adjudicators and courts want the second one.
Practical Steps Before the Next Delay Hits
Before the next project runs into a delay, it’s worth checking three things: does the subcontract actually mirror the notice periods in the head contract, does it deal with concurrent delay explicitly, and is someone on site actually updating the programme in real time rather than after the fact. None of that is exciting work, but it’s the difference between recovering a genuine delay claim and absorbing a cost that was never really yours to carry.
If a dispute is already brewing, getting a construction lawyer to review the notice history and programme records early, rather than after positions have hardened, usually changes the outcome. Baker Merz Construction Lawyers deals with exactly this kind of contract chain analysis for builders and developers across Brisbane, Melbourne, and Darwin, and the pattern is almost always the same: the fault was real, but the paperwork to prove it wasn’t.