JCT in a Nutshell

JCT stands for the Joint Contracts Tribunal, the body that publishes the JCT suite of standard form contracts. If you are asking what a JCT contract is, it is the most widely used family of building contracts in the UK. There are versions for traditional building work, design and build, and minor works, and, importantly for you, subcontract versions such as the Standard Building Sub-Contract and the Design and Build Sub-Contract.

JCT contracts are drafted in a traditional legal style. They set out each party's obligations, list the events that entitle the contractor to more time and money, and describe procedures for valuation, payment and disputes. On a subcontract, it is the main contractor who assesses and pays you. JCT publishes updated editions every few years, so check which edition yours is based on.

NEC in a Nutshell

NEC, originally the New Engineering Contract, is the other big family. The current edition is NEC4, though NEC3 is still in use. The subcontract version is the Engineering and Construction Subcontract.

NEC is written in plain, present-tense language and is built around project management. It leans on early warnings, an accepted programme that is kept up to date, and compensation events, which is how changes and delays are timed and priced. Instead of a contract administrator there is a Project Manager, who on a subcontract is the main contractor's representative.

The main options, A to F, differ in how price is handled, from a priced contract with an activity schedule (Option A) through to target cost and cost reimbursable. The option chosen is listed in the Contract Data.

Key Differences: Payment, EOT and Disputes

Style

• JCT: Traditional legal drafting with long clauses.
• NEC: Plain, present-tense language, built around a process.

Payment

• JCT: The standard form sets due dates, a payment notice within days of the due date, and a final date for payment 14 days after it. Subcontracts often change these periods.
• NEC: Built around assessment dates in the Contract Data. The Project Manager assesses the sum due and payment follows on a fixed timetable. The Construction Act notice rules still apply, usually through Option Y(UK)2.

Delay and extension of time

• JCT: Relevant Events are listed in the contract. You give notice when delay becomes reasonably apparent, and the main contractor decides on more time.
• NEC: Compensation events. These are usually notified within eight weeks of becoming aware of them, and entitlement is generally lost if you miss the window. The accepted programme is central.

Money for changes and delay

• JCT: Loss and expense is claimed separately for listed Relevant Matters, with supporting information. It is often argued over late in the job.
• NEC: Compensation event quotations deal with time and cost together, as the job runs, usually based on Defined Cost plus fee.

Disputes

• JCT: Adjudication is a statutory right. Arbitration or litigation is the final route named in the contract. Mediation is encouraged.
• NEC: Adjudication first, then a tribunal chosen in the Contract Data. Option W2 applies where the Construction Act does, and W3 adds a dispute avoidance board. Time limits for notifying disputes can be tight.



For more on how time works in practice, see our page on extension of time claims. For the money side, see loss and expense claims.

Which Is Better for Subcontractors?

Neither is better in the abstract. The form you are given matters less than how it has been amended and how well you manage it.

NEC's strength for a subcontractor is that time and money are dealt with together while the job is running, rather than being left for a final account argument. Its weakness is the unforgiving notice regime: miss the eight-week window, or whatever shorter period the subcontract sets, and a valid claim can disappear. NEC tends to reward good administration. Early warnings, a live programme and quotations submitted on time are what win claims.

JCT is more familiar to most site and commercial teams and is generally more forgiving on notices. The downside is that money for delay and disruption often has to be fought for after the event, and valuations and loss and expense claims can drag on to the final account. JCT tends to reward good records.

Under either form, look for amendments. Main contractors often add a schedule of amendments, or Z clauses in NEC, that shorten notice periods, widen the right to deduct money, or cut back the list of events that earn you time. Those changes are frequently the real cause of a dispute.

How Disputes Arise Under Each

Under JCT, the usual flashpoints are:

• Variations valued below what they cost you, or not valued at all
• Extension of time decisions that arrive late or are refused without reasons
• Loss and expense claims met with silence or repeated requests for more information
• Pay less notices that arrive late or without a clear calculation
• Contra-charges raised without evidence

Under NEC, they tend to be:

• Compensation events not notified in time, or notified and then left unanswered
• The main contractor not accepting your programme, or accepting it and then ignoring it
• Quotations rejected, or assessed by the Project Manager at less than you quoted
• Disagreement over what counts as Defined Cost
• Amended clauses that shorten time limits or shift risk onto you

Some of these end up in adjudication. Our guide to what adjudication is explains how that works.

Get Your Contract Reviewed

If you are not sure which form you are on, or what the amendments change, a contract review before you sign is cheaper than a fight afterwards. RJH reviews subcontracts for subcontractors and flags the clauses that carry risk: notice periods, payment terms, rights of deduction and the route for disputes.

If you already have a delay or an unpaid claim, we can look at what the contract entitles you to, whether that is more time, more money or both.