How do I claim an extension of time on a building job?
An extension of time moves the contract completion date, so you are not charged delay damages for a delay that was not your risk. It only works if your contract allows it, so check which events count and how to give notice. Give written notice as soon as the delay is apparent, and keep records to prove it. This is general guidance for England and Wales, not legal advice.
What an extension of time is
A building contract sets a completion date. If something outside your reasonable control delays the work, an extension of time (EOT) moves that date. While the extension runs, the client cannot claim delay damages from you.
An EOT is only available where the contract provides for it. Standard forms such as JCT list the events that qualify. Many short, informal or home-made contracts have no EOT clause at all. If yours has none and the client causes the delay, the legal position can be that time is "at large", which means the fixed completion date no longer applies and you must finish within a reasonable time. That is a worse place to argue from than a clear clause, so it is worth writing one into your terms.
An EOT is about time, not money. Extra costs caused by the delay are a separate claim under the contract, and under JCT they depend on a different list of events.
Relevant events and your own risk
The contract decides which delays earn time. Under the JCT forms they are called relevant events. The lists differ between editions, but those described in published commentary on the JCT forms include:
- exceptionally adverse weather
- force majeure
- work by statutory undertakers, such as the utility connecting your supply
- the client failing to give access to the site
- compliance with the client's instructions, such as a variation
- acts of prevention by the client
- strikes, epidemics and government intervention, in some editions
Parties can add to or change the list, so read your own contract. Anything not on the list is generally your risk. That usually includes your own labour shortages, late orders, a subcontractor's failure, ordinary bad weather and mistakes.
On weather, guidance on the JCT 2024 forms says it must be exceptional and adverse, and is judged against when the work was actually being done, not against your programme. A wet week in March on a job programmed for dry work is not automatically exceptional.
Give notice promptly
The contract will say how and when. For JCT Design and Build 2016, the contractor must notify the employer once it is reasonably apparent that progress is being or is likely to be delayed, and give particulars (clause 2.24, as described by a law firm's guide). Guidance on the 2024 JCT forms describes notice of delay as appearing to be a condition precedent, which means that missing it could cost you the extension. Whichever form you use, do not wait for the delay to finish before telling the other side.
Some contracts set a fixed period instead. NEC and FIDIC contracts, for example, use periods such as 8 weeks or 28 days. Follow the way of serving notice that the contract names. If the contract says writing to a named address, an email or a phone call to the client may not count. Cite the clause you are relying on.
You may also have a duty to take reasonable steps to limit the delay. Keep a note of what you did to cut it.
What to put in a delay notice
- the job, the contract and the date of the notice
- the event: what happened, when, and who or what caused it
- why it is a relevant event or delay event under your contract, quoting the clause
- how it affects the work: which activities, and the effect on the programme
- the delay you expect, in working days or calendar days, and the date you want the completion moved to
- a promise to update the notice if the position changes
- what you have done to reduce the delay
Keep it short and factual. Attach the evidence: diary pages, photos, instructions, emails. If the length of the delay is not yet known, say so and give your best estimate with the date you will confirm it. A late or vague notice gives the client grounds to challenge the claim.
Keep the records
A claim is only as good as the proof behind it. From the day work starts:
- site diary every day: who was on site, what was done, what was stopped and why, visitors, deliveries and instructions
- weather each day, with the times work stopped and started
- dated photos of the problem and of the state of the work
- a copy of every instruction, variation and request for information, and the date you got it
- delivery notes, and proof of when you ordered key items
- the programme, updated as the job goes on, so you can show what the event actually held up
- confirmation, such as an email, of what was agreed on site
Verbal instructions are the usual weak point. Confirm them in writing the same day.
Decision and liquidated damages
Under the JCT forms, the client or their contract administrator must respond within a set time. The 2016 Design and Build form allowed 12 weeks from receiving your particulars, while guidance on the 2024 forms gives 8 weeks or until the completion date, whichever is sooner. Check your own contract. A review after practical completion is also possible for the forms described.
Liquidated damages are an agreed fixed sum, usually a rate per day or week, that the client can claim for late completion that is your risk. The client does not need to prove the loss actually suffered. The rate is written into the contract. Under the JCT 2024 forms, a nil entry for the rate may stop the client claiming them.
The agreed sum must not be a penalty. The UK Supreme Court summary says the test is whether the clause imposes a detriment on the party in breach that is out of all proportion to any legitimate interest of the other party in enforcing the primary obligation. A reasonable daily rate linked to what a late finish really costs the client is the safer position.
If time is at large, liquidated damages generally cannot be claimed, and the client is limited to proving actual losses. That is why clients and their advisers also want a working EOT clause.
The client also has to follow the contract to deduct. For example, guidance on JCT 2024 Design and Build says the client needs a non-completion notice, and a written notice before the due date with a pay less notice. Do not assume a client can simply knock money off the final account.
Worked example: Brunel Terrace
A 12-week refurbishment at Brunel Terrace has a completion date of 24-07-2026 and liquidated damages of £150 a calendar day. The electricity network connection is held up by the statutory undertaker. The contractor sees it will cost 9 working days and gives written notice the same week, citing the relevant event clause, with the supplier's emails attached.
- extension granted: 9 working days from Friday 24-07-2026 takes in 27 to 31 July and 3 to 6 August, so the new date is Thursday 06-08-2026
- actual completion: Monday 10-08-2026
- late against the new date: 4 calendar days, so 4 x £150 = £600
- late against the old date, if no extension had been given: 17 calendar days, so 17 x £150 = £2,550
The notice and the paper trail were worth £1,950. How days are counted, and whether weekends are included, depends on your contract.
Sources
- Lester Aldridge: Construction A-Z, extensions of time
- Hill Dickinson: Claiming for delay and disruption and extensions of time
- Pinsent Masons (Out-Law): Liquidated damages
- NBS: JCT 2024 contract administrator guidance, November 2024
- UK Supreme Court: Cavendish Square Holding v Makdessi and ParkingEye v Beavis