Liquidated damages (LADs) are a fixed sum of money, agreed in advance and written into a construction contract, that a contractor must pay the employer for each day or week the works finish late. Because the figure is pre-agreed, the employer can deduct it without proving its actual loss — provided the clause is enforceable, the completion date is certain, and the correct payment notices are served.
In short: Liquidated damages (LDs) are a fixed sum the contractor must pay for each day or week of delay beyond the agreed completion date, set in advance in the construction contract. They are enforceable in England and Wales as long as the clause protects a legitimate commercial interest rather than acting as a penalty, following Cavendish Square Holding v Makdessi (2015). LDs may be reduced or unavailable where the contractor is granted an extension of time; if the clause is a penalty it is unenforceable and the employer must instead prove general damages.
This guide explains how liquidated damages work in JCT and NEC contracts, when a clause crosses the line into an unenforceable penalty after Cavendish v Makdessi, how extensions of time and the prevention principle protect (or destroy) the employer’s right to deduct, and what happens when a project is terminated before completion. It is written for employers, main contractors and sub-contractors operating under English law in 2026.
- Liquidated damages are a contractual pre-agreement of the sum payable for delay — the employer need not prove actual loss to recover them.
- A clause is enforceable unless it is a penalty: the modern test from Cavendish v Makdessi [2015] UKSC 67 asks whether the sum is “out of all proportion” to the innocent party’s legitimate interest in timely performance.
- If the employer causes delay and there is no mechanism to grant relief, the prevention principle can set time “at large” and wipe out the LAD entitlement — which is why robust extension of time claims matter to both sides.
- Liquidated damages accrue up to the date of termination; general (unliquidated) damages cover loss after that point — Triple Point Technology v PTT [2021] UKSC 29.
- Under JCT contracts you must issue the right notices — a non-completion certificate, a notice of intention to deduct, and a valid pay less notice — or the deduction can be reversed in adjudication.
- What we see in practice
- LADs sit alongside other recovery routes such as defective works claims; getting the contract mechanics right from the outset is the work covered in our guide to JCT contracts.
What are liquidated damages in a construction contract?
Liquidated damages — often abbreviated to LADs, LDs or “liquidated and ascertained damages” — are a sum the parties fix before any breach occurs, payable by the contractor when it fails to complete the works by the contractual completion date. The defining feature is certainty: rather than the employer having to prove what late completion actually cost it (lost rent, extended finance, alternative accommodation, professional fees), both sides agree a rate — commonly expressed as £X per day or per week — and that rate applies automatically.
For the employer, the attraction is speed and predictability. There is no need to quantify and evidence loss, and the contractor knows its exposure from day one and can price the risk. For the contractor, a properly drafted LAD clause is a protection as much as a liability: it caps what would otherwise be an open-ended claim for general damages. As the Supreme Court put it in Triple Point, the function of a liquidated damages clause is to provide a remedy that is “predictable and certain”.
Liquidated damages are a creature of contract. If a building contract is silent on delay damages, none are payable as “LADs” — the employer is left to a general damages claim instead. Equally, the rate is not a default figure: it must be inserted into the contract particulars. Where the box is left blank or marked “nil”, the courts have treated that as an exhaustive agreement that no damages for delay are recoverable, so the employer cannot fall back on general damages either. Drafting the rate is therefore one of the most consequential entries in the whole contract.
The penalty doctrine: genuine pre-estimate vs penalty after Cavendish v Makdessi
The modern test comes from Cavendish Square Holding BV v Makdessi and ParkingEye Ltd v Beavis [2015] UKSC 67 (judgment 4 November 2015). The Supreme Court moved away from the older “genuine pre-estimate of loss” language of Dunlop Pneumatic Tyre Co Ltd v New Garage & Motor Co Ltd [1915] AC 79 and asked instead whether the clause imposes a detriment out of all proportion to the innocent party’s legitimate interest in performance. A liquidated damages figure that protects a genuine commercial interest is enforceable even if it is not a precise forecast of loss.
An LAD clause is only worth having if it is enforceable. English law refuses to enforce a contractual clause that is a penalty — a sum designed to frighten the other party into performance rather than to address the consequences of breach.
For a century the governing test came from Dunlop Pneumatic Tyre Co Ltd v New Garage & Motor Co Ltd [1915] AC 79, where Lord Dunedin asked whether the figure was a “genuine pre-estimate” of the likely loss, or instead “extravagant and unconscionable” compared with the greatest loss that could conceivably flow from the breach. If it was a genuine pre-estimate, it was enforceable; if it was a sum held in terrorem of the contractor, it was a penalty and void.
The Supreme Court re-cast that test in Cavendish Square Holding BV v Talal El Makdessi, heard with ParkingEye Ltd v Beavis, [2015] UKSC 67 (judgment 4 November 2015). The court held that the “genuine pre-estimate” language was too narrow. The real question is whether the clause is a secondary obligation that imposes a detriment on the contract-breaker out of all proportion to any legitimate interest of the innocent party in the enforcement of the primary obligation. The modern two-stage test is therefore:
- Identify the legitimate interest the clause protects (which can extend beyond pure compensation to wider commercial interests in performance); then
- Ask whether the sum is exorbitant or unconscionable — “out of all proportion” to that interest.
Two practical consequences follow for construction LADs. First, the figure no longer has to be a precise forecast of loss; a sum that is a reasonable measure of the employer’s legitimate interest in completion on time will stand even if it exceeds the loss eventually proved. Second, the doctrine only bites on negotiated bargains between commercial parties; courts are slow to strike down a freely agreed rate where the parties had comparable bargaining power. The burden of showing a clause is a penalty rests on the party challenging it.
| Feature | Old test (Dunlop, 1915) | Modern test (Cavendish, 2015) |
|---|---|---|
| Core question | Is the sum a genuine pre-estimate of loss? | Is the sum out of all proportion to a legitimate interest? |
| Permitted purpose | Compensation for breach only | Compensation plus wider legitimate commercial interests |
| Threshold for a penalty | “Extravagant and unconscionable” vs greatest conceivable loss | “Exorbitant” / “unconscionable” vs the legitimate interest protected |
| Effect on commercial deals | Clauses struck down more readily | Freely negotiated rates more readily upheld |
You can read the judgment in full on the UK Supreme Court case file for Cavendish v Makdessi.
How liquidated damages operate in JCT and NEC contracts
The two dominant standard-form families in UK construction handle delay damages differently in their mechanics, though both rest on the same legal foundations.
JCT contracts
In the JCT suite — for example the Design and Build 2024 and Standard Building Contract 2024 — liquidated damages are switched on by inserting a rate in the Contract Particulars. The architect/contract administrator (or the Employer under D&B) must first issue a certificate or notice of non-completion, confirming the contractor failed to complete by the Completion Date. The Employer then has to give two further notices before the final date for payment of the relevant certificate: a notice that it may require payment of, or will deduct, liquidated damages, and a pay less notice if it intends to withhold the sum. Miss the sequence and the deduction is vulnerable.
The JCT 2024 editions added a useful clarification at clause 2.29.5 (D&B numbering): where termination occurs before practical completion, the liquidated damages provisions still apply to the period between the Completion Date and the date of termination — codifying the Triple Point outcome discussed below.
NEC4 contracts
The NEC4 Engineering and Construction Contract takes the opposite default. The core clauses are silent on delay damages; if the Client wants them, it must select secondary Option X7 (Delay damages) and state the rate in the Contract Data. The Project Manager deducts the damages from the amount due when assessing payment, and the damages stop running once the works are taken over (Completion). X7 can be combined with X5 (Sectional Completion) to set separate rates for each section, and is conceptually distinct from any low-performance damages an organisation might add by separate option.
| Issue | JCT (D&B / SBC 2024) | NEC4 ECC |
|---|---|---|
| Default position | LADs apply if a rate is inserted | No delay damages unless Option X7 chosen |
| Where the rate sits | Contract Particulars | Contract Data Part One |
| Trigger document | Non-completion certificate/notice + deduction notices | Project Manager’s assessment of the amount due |
| Sectional rates | Via Sectional Completion provisions | Option X7 with Option X5 |
| When damages stop | Practical Completion | Completion / take over |
The completion date, extensions of time and the prevention principle
Liquidated damages run from a single fixed point: the contractual completion date. Everything therefore depends on that date being certain and properly maintained. This is where extensions of time and the prevention principle come in.
The prevention principle is a long-standing rule of English law: a party cannot insist on performance of an obligation where it has itself prevented the other party from performing. In construction, if the employer causes delay — by issuing late variations, failing to give access, or supplying late information — and there is no contractual mechanism to move the completion date, the principle sets time “at large”. The fixed completion date falls away, the contractor need only finish within a reasonable time, and crucially the employer loses its right to deduct liquidated damages, because there is no longer a date from which they can run. The principle traces back to Peak Construction (Liverpool) Ltd v McKinney Foundations Ltd (1970).
The answer, built into every standard form, is the extension of time (EOT) mechanism. By granting the contractor extra time for “relevant events” (JCT) or “compensation events” affecting the Completion Date (NEC), the contract administrator resets the completion date to a new, certain point — preserving the LAD regime for the contractor’s own culpable delay. Far from being a giveaway to the contractor, the EOT clause is the very thing that protects the employer’s liquidated damages. A well-run extension of time claim is therefore central to both parties’ positions: the employer needs the date moved to keep its LADs alive, and the contractor needs it moved to shrink the period over which LADs accrue.
Caps and exclusions on liquidated damages
Most well-drafted contracts cap the contractor’s total liability for delay damages — for example at 5%, 10% or 15% of the contract sum — and may also include an overall cap on total liability. Caps give the contractor certainty when pricing and prevent a modest weekly rate compounding into an existential liability on a long delay. From the employer’s side, a cap that is set too low can leave it under-compensated; from the contractor’s, an uncapped clause is a serious risk that should be negotiated at tender stage.
Two drafting points repay close attention. First, whether the LAD cap is a cap only on delay damages, or an aggregate cap on all liability — in Triple Point the cap was held to apply to the liquidated damages, which materially reduced the recovery. Second, whether carve-outs (for fraud, negligence, wilful misconduct, or specified indemnities) sit above the cap. The interaction between caps, carve-outs and the LAD clause is one of the most heavily litigated areas of construction drafting, and it should never be left to a boilerplate template.
Liquidated damages vs general (unliquidated) damages
It is essential to distinguish the two routes for recovering delay loss:
| Liquidated damages | General (unliquidated) damages | |
|---|---|---|
| Source | Agreed in the contract before breach | Assessed by a court/tribunal after breach |
| Proof of loss | Not required — rate applies automatically | Employer must prove and quantify actual loss |
| Certainty | High — fixed rate per day/week | Low — depends on evidence and causation |
| Risk of over/under-recovery | Capped by the agreed rate and any cap | Recovers proven loss, subject to remoteness/mitigation |
| When it applies | While a valid LAD clause governs the delay | If no LAD clause, or the clause fails/falls away |
The practical point is that the two are usually mutually exclusive for the same period of delay. Where a valid LAD clause applies, the employer takes the agreed rate and cannot also claim general damages for that delay — even if its true loss was higher. Conversely, if the LAD clause is unenforceable as a penalty, or has fallen away because time is at large, the employer is not left without a remedy: it can pursue general damages, but must then shoulder the burden of proving its loss.
What happens on termination: Triple Point Technology v PTT
In Triple Point Technology Inc v PTT Public Company Ltd [2021] UKSC 29 the Supreme Court confirmed that, unless the contract clearly says otherwise, liquidated damages for delay accrue up to the date of termination as an accrued right, even for works the contractor never completed. After termination the employer’s remedy for any further delay is general damages.
A recurring question is whether the employer can still claim liquidated damages for delay on works that were never finished because the contract was terminated. The Supreme Court settled this in Triple Point Technology Inc v PTT Public Company Ltd [2021] UKSC 29 (judgment 16 July 2021).
PTT engaged Triple Point to supply and implement a commodities-trading software system under a milestone-payment contract. The works fell into serious delay, PTT terminated, and engaged a replacement contractor. The contract’s LAD clause charged 0.1% of undelivered work per day of delay “up to the date [the customer] accepts such work”. The Court of Appeal had held that, because the works were never accepted, liquidated damages were payable only on the parts actually completed — a result it acknowledged departed from the “orthodox analysis”.
The Supreme Court unanimously reversed that. Lady Arden held the Court of Appeal’s approach was “inconsistent with commercial reality and the accepted function of liquidated damages”. The orthodox position was restored: liquidated damages accrue up to the date of termination, and general damages cover the loss thereafter, unless the contract clearly says otherwise. PTT recovered US$3,459,278.40 in liquidated damages for delay up to termination. The decision also addressed the contractual cap, holding the LADs were subject to it on the facts — a reminder that cap drafting decides the size of recovery.
For 2026 drafting, the lesson is twofold: include clear words on how LADs operate at and after termination (which the JCT 2024 forms now do expressly), and price the cap deliberately, because it can bite on the LAD claim itself.
Deduction mechanics and pay less notices
Even a watertight LAD clause can be defeated by a procedural slip. Construction contracts in the UK are overlaid by the payment regime in the Housing Grants, Construction and Regeneration Act 1996 (as amended by the Local Democracy, Economic Development and Construction Act 2009). The key provision is section 111: the payer must pay the “notified sum” on or before the final date for payment unless it has served a valid pay less notice in time, specifying the sum it considers due and the basis of calculation.
Because deducting liquidated damages means paying the contractor less than the sum otherwise certified, the deduction must be carried through the pay less notice machinery. The typical sequence under a JCT contract is:
- The completion date passes without practical completion; the contract administrator issues a non-completion certificate/notice.
- The Employer gives written notice that it may require payment of, or will deduct, liquidated damages, stating the rate and the period.
- The Employer serves a valid pay less notice before the final date for payment, setting out the reduced sum and how the LAD deduction was calculated.
Get any step wrong — an out-of-time pay less notice, a missing non-completion certificate, or a deduction that exceeds the notice — and the contractor can launch a “smash and grab” adjudication to recover the “notified sum” in full, with the LAD argument left for another day. Adjudication under the Act is fast (a decision in 28 days from referral, extendable by agreement) and the decision is binding until finally determined, so notice discipline is not a formality — it is decisive. You can read section 111 on legislation.gov.uk and the wider scheme in the Housing Grants, Construction and Regeneration Act 1996.
A worked numerical example
Scenario — “Riverside Mews” (illustrative). An employer engages a contractor under JCT D&B 2024 to build a small residential block. The Contract Particulars set liquidated damages at £2,500 per week (or part of a week) of delay, with an LAD cap of 10% of the £1,200,000 contract sum = £120,000. The Completion Date is 1 May 2026.
Step 1 — the raw delay. The contractor reaches practical completion on 7 August 2026, 14 weeks after the Completion Date.
Step 2 — apply extensions of time. The contract administrator grants a 4-week EOT for an employer-caused delay (a late design instruction) and a 2-week EOT for exceptionally adverse weather — 6 weeks in total. The revised completion date moves to 12 June 2026. Granting the employer-caused EOT is what keeps the LAD regime alive: without it, the prevention principle could have set time at large and lost the employer all its LADs.
Step 3 — the culpable delay. 14 weeks raw delay − 6 weeks EOT = 8 weeks of contractor culpable delay.
Step 4 — calculate the LADs. 8 weeks × £2,500 = £20,000. This is well within the £120,000 cap, so the full £20,000 is recoverable.
Step 5 — deduct correctly. The employer issues the non-completion notice, then a notice of intention to deduct, then a valid pay less notice quantifying the £20,000 before the final date for payment of the next certificate — and withholds £20,000. Had the delay run to, say, 60 weeks (£150,000), the cap would limit recovery to £120,000.
What we see in practice
In our advisory work, liquidated damages clauses cause the most trouble not when the rate is too high but when the mechanics around them are neglected. The most common pattern we see is an employer continuing to levy delay damages after failing to operate the extension-of-time machinery, which can engage the prevention principle and put the whole clause at risk. We also see “nil” or blank rates left in the contract particulars, which a court may read as an agreement that no delay damages are payable at all. Getting the completion date, the extension-of-time procedure and the deduction notices right is usually worth far more than arguing about the rate after the event.
Common mistakes with liquidated damages
- Leaving the rate blank or “nil”. Courts may treat this as agreement that no delay damages are payable — closing off general damages too.
- Failing to grant an EOT for employer delay. This risks the prevention principle setting time at large and destroying the whole LAD entitlement.
- Setting a rate with no rational basis. A figure plucked from the air invites a penalty challenge under Cavendish; keep a note of how the rate was derived.
- Missing the pay less notice or serving it late. The contractor can recover the full notified sum in a “smash and grab” adjudication regardless of the delay.
- Assuming LADs vanish on termination. After Triple Point, they accrue up to termination — and may be limited by the cap.
- Ignoring the cap drafting. Whether the cap covers LADs, and whether carve-outs sit above it, can change recovery by hundreds of thousands of pounds.
Can liquidated damages be challenged as a penalty in 2026?
Yes, but it is harder than many assume. The burden is on the contractor to show the rate is “out of all proportion” to the employer’s legitimate interest in timely completion. A rate grounded in a sensible assessment of likely consequences — even a rough one — agreed between commercial parties of comparable bargaining power, will usually survive.
Do liquidated damages apply to sub-contractors?
They can, if the sub-contract contains its own LAD clause or passes down the main-contract liability. Many sub-contracts instead make the sub-contractor liable for the main contractor’s losses (including any LADs it must pay the employer) as general damages, so the wording of the back-to-back provisions is critical.
How Hayhills can help
Liquidated damages are won or lost long before any dispute — in the drafting of the rate, the cap and the notice machinery, and then in the discipline of running them correctly during the project. Hayhills acts directly on the advisory side of construction: reviewing and drafting LAD, EOT and cap provisions in your JCT or NEC contract; building a defensible record for the rate so it withstands a penalty challenge; managing the pay less notice sequence so deductions stick; and supporting you through adjudication, where most delay-damages disputes are resolved. Where a matter must go to court enforcement or insolvency, we advise on strategy and introduce and coordinate a regulated solicitor to handle the reserved court steps, so you keep one joined-up team.
Facing a liquidated damages deduction, or drafting a clause you need to be enforceable? Speak to the Hayhills construction advisory team on 0203 581 5789 or contact us here for a confidential, commercial review.
Frequently asked questions
What are liquidated damages in construction?
They are a fixed sum, agreed in the contract before any breach, that the contractor pays the employer for each day or week the works finish late. Because the figure is pre-agreed, the employer can deduct it without proving its actual loss, provided the clause is enforceable and the right notices are served.
How are liquidated damages calculated?
You apply the contractual rate (for example £2,500 per week) to the period of the contractor’s culpable delay — that is, the delay remaining after any extensions of time are deducted — up to any contractual cap on liquidated damages.
Are liquidated damages the same as a penalty?
No. A penalty is unenforceable. Under Cavendish v Makdessi [2015] UKSC 67, a clause is a penalty only if it imposes a detriment out of all proportion to the innocent party’s legitimate interest in timely performance. A reasonably set rate is enforceable.
What is the prevention principle?
It is the rule that a party cannot enforce an obligation it has prevented the other party from performing. If the employer causes delay with no mechanism to extend time, time can be set “at large”, the fixed completion date falls away, and the employer loses its right to liquidated damages.
Can you claim liquidated damages after termination?
Yes. In Triple Point v PTT [2021] UKSC 29 the Supreme Court confirmed liquidated damages accrue up to the date of termination, with general damages available for loss after that, unless the contract clearly provides otherwise.
What is a pay less notice?
Under section 111 of the Housing Grants, Construction and Regeneration Act 1996, the payer must pay the notified sum by the final date for payment unless it serves a valid pay less notice in time, stating the reduced sum and how it was calculated. Deducting liquidated damages requires this notice.
Is there a cap on liquidated damages?
Only if the contract includes one — commonly a percentage of the contract sum such as 5%, 10% or 15%. Caps are not automatic; they must be drafted in. Whether the cap covers liquidated damages specifically can decide the size of recovery.
Do liquidated damages apply under NEC4?
Only if the Client selects secondary Option X7 (Delay damages) and states a rate in the Contract Data. The NEC4 core clauses are silent on delay damages, so without X7 none are payable.
What happens if the liquidated damages rate is left blank?
The courts have treated a blank or “nil” entry as agreement that no damages for delay are recoverable — which can prevent the employer from claiming general damages for the same delay too. The rate is a critical entry.
Can I claim general damages instead of liquidated damages?
Not while a valid liquidated damages clause governs the delay — the agreed rate applies even if your true loss is higher. If the clause is an unenforceable penalty or time is at large, you may pursue general damages, but you must then prove your actual loss.
This article is for general information only and does not constitute legal or accountancy advice. Hayhills Limited, trading as Hayhills Legal Advisory, provides non-reserved legal advisory services. Always check current requirements at GOV.UK.