What is a time bar?
A time bar is a contract clause that says: if you want to claim something — more time, more money, a variation — you have to tell the other side within a set period, and in a set way. Miss the window, and the entitlement can be gone, even if the underlying claim was completely valid.
Time bars show up wherever the contract lets one party ask for an adjustment. Typical triggers include:
- ✓Delays and extensions of time: usually an early notice of delay, followed by a formal claim for the time.
- ✓Variations and directed changes: some contracts require written notice before, or soon after, you do the extra work.
- ✓Latent conditions and unforeseen site conditions: normally a prompt notice once you encounter them.
- ✓Delay costs and other cost claims that depend on an earlier notice being given.
- ✓Defects, insurance and termination-related notices.
The exact requirements differ from contract to contract, which is exactly why they get missed.
Are time bars enforceable in Australia?
As a general rule, yes. Australian courts have generally been willing to hold parties to the notice terms they agreed to, and a claim made outside the prescribed period can be barred. There are exceptions, and outcomes turn on the exact wording: whether the clause says a late claim is barred, or makes notice a condition of the entitlement, and whether other legal arguments are in play.
The practical takeaway is simple: don't plan on a court rescuing a late notice. Plan on giving the notice on time.
What it looks like in practice: AS 4000
Take one of the most widely used standard forms, AS 4000. Under the 1997 edition, clause 34.2 asks for a written notice of delay to be given promptly, and clause 34.3 requires a written claim for an extension of time within 28 days of when the contractor should reasonably have become aware of the cause of the delay. Whether a late claim is actually barred under an unamended AS 4000 has been debated, but principals commonly amend the form to remove any doubt, and newer editions have changed the wording again.
- The Special Conditions usually win. A 28-day period in the general conditions can become 5 or 10 business days in the amendments, and "promptly" can become a hard deadline. The standard form tells you where to look, not what your contract says.
Why notices get missed
- Nobody read the notice clauses at the start. They’re spread across the general and special conditions and rarely sit in one place.
- The trigger is fuzzy. Many periods run from when you became aware of the cause, or should have, not from when it finally hurt the program.
- The method is wrong. The wrong recipient, the wrong address, or an email where the contract needs a formal letter can undo an otherwise timely notice.
- The person on site doesn’t know. The event happens on site, but the notice is the commercial team’s job, and the message arrives days late.
A practical checklist
- ✓On day one, list every notice obligation in the contract, general and special conditions: what triggers it, the deadline, who it goes to and how it must be sent.
- ✓Work out how each period is counted: calendar or business days, and whether public holidays are excluded.
- ✓Give early, protective notice. If you’re unsure whether something is a delay or a variation, notify anyway and reference the clause.
- ✓Follow the contract’s method exactly: the named recipient, the address and the required form.
- ✓Tie site records to the notice: diaries, photos and dates that show when you became aware.
- ✓Make one person accountable for notices, and make sure site staff flag events the same day.
- ✓If you’ve already missed a deadline, don’t sit on it. Give notice now and get advice promptly; depending on the contract and the circumstances, there may still be options.
Where software can help
Tracking dates and making sure the right notice goes out is a consistency problem, which is where software can help. AIgile's Smart Contract Administrator helps you keep track of contract deadlines and draft notices from them, and Site Companion lets site staff flag an event from their phone and start a notice from it. Like any AI tool, it can miss or misread a clause, so treat what it produces as a starting point and check it against the contract itself.
Common questions
What's the difference between a notice of delay and an extension of time claim?
Under forms like AS 4000 they are two steps: an early notice that something is likely to cause delay, then a formal, substantiated claim for the time. Some contracts collapse the two into one, so check yours.
Does it matter if the other side already knew about the problem?
Possibly, but don't rely on it. Many clauses require formal written notice regardless of what the other side knew, so treat informal knowledge as no substitute for a compliant notice.
Are payment claims subject to time limits too?
Yes. Separately from your contract, Security of Payment laws set their own strict deadlines, and they vary by state. Our plain-English guide to Security of Payment covers them.
Can I still claim if I missed the deadline?
It depends on the clause, the circumstances and the state. Some contracts soften strict deadlines and there can be other routes, but it is fact-specific, so get advice as soon as you realise.
This article is general information, not legal advice. Contracts differ and amendments matter. Check your own contract and get advice from a qualified Australian lawyer before relying on it.