JCT 2024 should not be signed on 2016 assumptions.
JCT 2024 is now the current generation of the JCT contract suite. For contractors, the commercial risk is not simply that a new edition exists. The risk is signing a familiar-looking contract on old assumptions. Standard forms are often treated as known quantities. Commercial teams recognise the structure. Project teams recognise the language. Directors may assume the risk profile is broadly understood because the contract carries the JCT name. But that assumption can be dangerous. The issue is rarely the unamended form in isolation. The real risk usually sits in the contract particulars, schedules, amendments, employer’s requirements, design responsibility matrix, pricing documents and bespoke provisions that alter how the form operates in practice. For contractors, the question should never be: is this a JCT contract? The better question is: what has this JCT contract become once amended, completed and connected to the project documents?
Why the edition matters
The publication of the JCT 2024 suite should prompt contractors to revisit their standard contract review process. A new edition is not just an administrative update. It is an opportunity for employers, main contractors and professional teams to refresh risk allocation, update schedules, adjust notice procedures, revise payment wording and introduce obligations connected to building safety, design responsibility, programme management, insurance, dispute resolution and termination.
That matters because contract risk is often accepted before the project team fully understands it. Tender periods are compressed. Negotiation may focus on price, programme and headline liability caps. The detailed machinery of the contract may receive less attention until the project is already under pressure. By then, the contractor is no longer deciding whether to accept the risk. It is trying to administer the risk it has already accepted.
The risk is most acute where commercial teams rely on experience of earlier JCT forms without reviewing the live document in detail. Even familiar clauses can operate differently once amended. A small change to notice timing, loss and expense procedure, relevant event wording, payment due dates, pay less notice wording, design responsibility or termination rights can materially alter the contractor’s position. A standard form is not a standard risk once it has been amended.
Where contractors should look first
For contractors, the practical review should begin with the provisions that most directly affect cashflow, time, change and recovery. Payment should be reviewed carefully. The dates for applications, due dates, final dates for payment, payment notices, pay less notices and final account procedures determine how cash moves through the project. If those mechanisms are unclear, compressed or heavily amended, cashflow risk increases. A contractor may be entitled in principle but still exposed in practice if the payment regime is not administered precisely.
Change and valuation provisions are equally important. Variations, instructions, changes to scope, design development, provisional sums and employer requirements all need a clear route into valuation. If the contract narrows what counts as a change, imposes strict procedural requirements, or requires particular substantiation before value can be recognised, the contractor must know that before the work is carried out.
Time provisions require the same discipline. Extensions of time are not simply a matter of showing that the project became difficult. The contractor must understand the relevant events, notice requirements, particulars, assessment process and any amendments dealing with concurrency, mitigation or programme obligations. Where the contract has been amended to shift more time risk onto the contractor, delay entitlement may be harder to preserve than the project team expects.
Loss and expense should not be assumed to follow automatically from an extension of time. Time and money are separate routes. A contractor may secure relief from liquidated damages but still struggle to recover prolongation or disruption cost if the contract requires separate notice, proof, causation and substantiation.
Termination provisions also need careful review. The Supreme Court’s decision in Providence Building Services Ltd v Hexagon Housing Association Ltd has already shown that even familiar JCT termination wording requires careful sequential analysis. Contractors should not assume that repeated default, late payment or serious commercial frustration automatically creates an immediate right to terminate. The contractual route must be followed precisely.
The amendment risk
The central danger is not that JCT 2024 is unfamiliar. The danger is that it appears familiar while the risk has moved. Amendments can convert a balanced standard form into a materially different commercial bargain. They can tighten notice requirements, restrict entitlement, widen design responsibility, increase reporting duties, alter insurance obligations, change payment timing, expand set-off rights, modify termination consequences or reshape the dispute resolution process.
This is where contractors can lose value early. A project may be priced on the assumption of a standard JCT risk profile, while the executed contract contains a different allocation altogether. The result is margin exposure before the first instruction is issued. That risk is not always obvious from the front page of the contract. It often sits in the schedule of amendments, the employer’s requirements, the preliminaries, the contract particulars, appendices, bespoke Z clauses or supplemental provisions. The contract must therefore be read as a whole, not as a label. For contractors, this is particularly important where they are under pressure to proceed quickly. Starting works before the contract position is fully understood may feel commercially necessary, but it can leave the contractor administering obligations it never properly priced, negotiated or operationalised.
The practical message for contractors
The practical lesson is that JCT familiarity should not replace contract analysis. Before signing, contractors should review the actual risk allocation, not the assumed risk allocation. That means checking the contract particulars, amendments, schedules, employer’s requirements, design responsibility, payment machinery, extension of time procedure, loss and expense provisions, termination clauses, insurance obligations, limitation wording and dispute resolution route.
The review should not be limited to legal wording. The contractor should also ask whether the project team can actually administer the contract in practice. If the contract requires notices within short timescales, can the site team identify the triggering events? If loss and expense requires detailed substantiation, are cost records being captured properly? If programme updates are central to delay entitlement, is the programme being maintained to the required standard? If design responsibility has moved, does the contractor understand where that responsibility starts and ends?
This is where Legalbuild’s concern is practical rather than academic. A difficult clause is not only a drafting issue. It becomes a live-project management issue. The contract must be translated into daily discipline: notices, records, instructions, applications, programmes, valuations, correspondence and escalation decisions. If that translation does not happen, the contractor may only discover the true effect of the contract once there is a dispute. At that point, the problem is harder to correct. The contractor may have missed notices, failed to preserve evidence, accepted design risk unknowingly, submitted applications in the wrong form, or allowed change to proceed without protecting entitlement.
Why this matters for recovery
Recovery positions are not built at the end of the project. They are built through the way the contract is understood and administered from the outset. A contractor seeking payment, an extension of time, loss and expense, variation recovery or final account value will usually need to show more than commercial unfairness. It will need to show the contractual route to entitlement and the evidence supporting that route.
That is why the JCT 2024 assumption trap matters. If the contractor has misunderstood the contract at the beginning, the evidential structure may be wrong throughout the project. Notices may be late. Records may not address the correct contractual test. Programme evidence may not support the extension of time route. Valuation material may not meet the substantiation requirements. Correspondence may describe events commercially but not connect them to the relevant contractual mechanism. The result is progressive weakening. The contractor may still have a genuine grievance, but the recoverable position may be narrower, less certain and more difficult to advance.
Legalbuild’s view
For Legalbuild, JCT 2024 reinforces a core commercial point: contract risk is shaped before delivery begins, but it is won or lost during administration. Contractors should not treat standard forms as safe simply because they are widely used. Widely used contracts still need disciplined review. Widely used contracts still need to be administered properly. Widely used contracts can still become heavily employer-friendly through amendment.
The strongest position is built by understanding the contract before work starts, identifying onerous amendments early, and aligning project administration with the actual mechanisms that govern payment, change, delay, loss and expense, termination and dispute escalation. That is where value is protected. A contractor that understands the contract early can price risk more accurately, negotiate unacceptable provisions, issue notices correctly, preserve evidence, control change, protect time entitlement and prepare for adjudication if necessary. JCT 2024 should therefore be treated as a live commercial document, not a familiar label. The name on the form may be familiar. The risk inside it still needs to be tested.
Source note: JCT 2024 Edition; JCT Target Cost Contract 2024 release materials; Providence Building Services Ltd v Hexagon Housing Association Ltd [2026] UKSC 1.
