Construction Claims
The SCL Protocol, in Practice · Part 3 of 24
Extension of Time: What Are You Actually Measuring?
An extension of time isn't a reward for a project running late. It measures one specific thing — the effect of Employer Risk Events on the critical path to a contractual completion milestone. It nets out your own delays, it doesn't automatically hand you money, and it protects the Employer too by keeping the completion date alive.
An extension of time isn’t a reward for “the project ran late.” It measures one specific thing: the effect of Employer Risk Events on the critical path to a contractual completion milestone. It nets out your own delays and it doesn’t automatically hand you money. And the part people forget — the EOT machinery protects the Employer too, by keeping the completion date (and the liquidated-damages mechanism) alive instead of letting time drift “at large.”
The construction-site version
The programme says you’re 90 days behind. In the claim meeting you ask for 90 days’ EOT, because — obviously — you’re 90 days late.
Then the assessment starts pulling the 90 days apart. Thirty of those days trace to late Employer information on the critical path. Forty trace to a variation, also critical. But twenty days were your own subcontractor no-shows, sitting on the driving path in their own window. Suddenly “90 days late” and “entitled to 90 days” are two very different numbers. The lateness is a fact about the calendar. The entitlement is a fact about cause, criticality and contract — and it’s almost never the whole slip.
The technical bit
Start with purpose. The Protocol frames EOT as serving both parties. For the Contractor, an EOT relieves it from liquidated damages for the period of delay caused by Employer Risk Events, and gives it more time to complete. For the Employer, granting an EOT establishes a new completion date, prevents time for completion becoming “at large,” and lets the Employer plan its own downstream activities.
That second point is the one that gets missed. If an Employer act of prevention delays the works and there’s no effective mechanism to extend time, time can become “at large” — the obligation collapses to completion within a reasonable time, and the liquidated-damages regime can fall away. The EOT clause exists partly to stop that happening. So an EOT isn’t purely a concession to the Contractor; it’s the device that keeps the whole time-and-LDs structure intact.
Now what you actually measure. An EOT reflects the effect of Employer Risk Events on completion, assessed via the critical path to the relevant contractual milestone. Two disciplines follow. Criticality: only delay that affects the path driving completion counts — a delayed activity with spare float that never becomes critical doesn’t move your completion date. Net, not gross: you’re isolating the Employer-risk critical delay, not banking the total project slip.
And keep two things separate that people reflexively merge — time and money. The Protocol is blunt about it: entitlement to an EOT does not automatically carry entitlement to compensation, and vice versa. The EOT answers “how much longer do you have?” Your right to be paid for that time lives in other provisions of the contract, or at law — a question of who carries the risk.
How three roles should read it
Think in net delay to the completion milestone, not gross slip. Your tools: a completion milestone with real logic behind it (not a hard constraint faking the date), honest total float, and updates that show where the driving path actually ran when each event bit. If your programme can’t show which path was critical when the Employer event occurred, you can’t size the EOT properly — you can only assert it.
Build the EOT case around three things together: causation to Employer Risk Events, criticality, and the completion milestone. Then, separately, build (or don’t) the compensation case, because the EOT doesn’t win it for you. Watch the contract’s notice and substantiation requirements religiously; a strong entitlement can still be knocked out by a missed contractual step.
"We’re X days late" is a calendar statement, not an entitlement. Before you commit to a number in a meeting, understand how much of the slip is Employer-risk, critical, and properly notified — that’s your EOT ballpark — and remember it’s a different question from whether you’ll be paid for the extension. Two doors, two keys.
The trap
Equating the EOT with the total lateness (gross = net), and assuming an EOT automatically brings prolongation money. Both are false, and both are expensive assumptions to carry into a negotiation.
Baseline contractual completion: 30 June. Event A — Employer variation, on the critical path, causes 20 days’ critical delay, notionally pushing completion to 20 July. Event B — Contractor’s own labour shortfall, on the driving path but in a separate, later window (not concurrent with A), causes 8 days’ critical delay, pushing actual completion to 28 July.
Actual completion: 28 July — 28 days late (gross). But the EOT entitlement (Employer risk, critical, subject to the contract) is the 20 days from Event A. The 8 days from Event B are the Contractor’s own, potentially exposing it to liquidated damages for that window. “28 days late” and “20 days’ EOT” are both correct, and the gap between them is the whole point. Overlap the two events in the same window and the analysis changes — which is why concurrency is its own subject.
What the Protocol says — and doesn’t
It treats the purpose of an EOT as relieving the Contractor from LDs for Employer-risk delay while, for the Employer, establishing a new completion date and preventing time becoming “at large.” It assesses the effect of delay on completion via the critical path, and it separates the time question from the money question — an EOT does not automatically lead to compensation, and vice versa.
What it does not say:
- That the EOT equals the total project delay.
- That your own (non-concurrent) delays are the Employer’s problem.
- That an EOT automatically entitles you to prolongation cost.
- That it relieves you of the contract’s notice and substantiation requirements.
”The project is 90 days late, so we’re entitled to 90 days’ EOT.”
An EOT measures Employer-risk delay to the critical path and the completion milestone, net of your own (non-concurrent) delays and subject to the contract. Gross lateness and EOT entitlement are rarely the same number.
Watch the difference between gross slip on the completion milestone and net Employer-risk critical delay. Interrogate whether the completion date is driven by real logic or propped up by a hard constraint. Check total float on the paths around each event, and make sure your data date and updates actually capture which path was critical when the event occurred — otherwise you can’t defend the number.
Evidence check
The accepted baseline and its updates; records tying each Employer Risk Event to the critical path at the relevant time; the contractual completion milestone; delay notices and particulars in the contractual form; instructions, variations and correspondence establishing timing; and — separately, if pursuing money — the cost records supporting prolongation. Relevance depends on the facts and the contract.
Rishi’s takeaway
- An EOT measures Employer-risk critical delay to a completion milestone — not the total slip.
- It protects the Employer too: it keeps the completion date and the LDs mechanism alive, preventing time “at large.”
- Net, not gross — isolate the Employer-risk critical delay from your own.
- Time and money are separate doors: an EOT doesn’t automatically bring prolongation cost.
An EOT answers how much longer you have — not how much you’re owed. Two doors, two keys.
References — Society of Construction Law, Delay and Disruption Protocol, 2nd Edition, February 2017: purpose of an extension of time; effect of Employer Risk Events on completion via the critical path; the separation of time and money; prevention and time “at large.” The Protocol has no force of law unless incorporated into a contract. Educational commentary; not legal advice.
Common questions
What does an extension of time actually measure?
The effect of Employer Risk Events on the critical path to a contractual completion milestone — net of the contractor's own delays, and subject to the contract. It is rarely the same figure as the total (gross) lateness.
Is an EOT the same as the total project delay?
No. It is net, not gross — only Employer-risk delay that was actually critical counts. A project 28 days late might carry only 20 days of entitlement if 8 days were the contractor's own.
What does time at large mean?
If an Employer act of prevention delays the works and there is no effective mechanism to extend time, the obligation can collapse to completion within a reasonable time and the liquidated-damages regime can fall away. The extension-of-time clause exists partly to prevent this.
Does an extension of time entitle you to money?
Not automatically. Under the Protocol, time and money are separate questions — an extension of time does not automatically carry compensation, and vice versa. Prolongation cost lives in other provisions of the contract or at law.
Do you still need to serve a delay notice if you are entitled to an EOT?
Yes. A strong entitlement can still be defeated by a missed contractual notice or substantiation step; the contract's machinery must be followed.
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