JCT contracts explained for subcontractors

A JCT contract is a standard form published by the Joint Contracts Tribunal, which is what JCT stands for. Main contractors use a JCT main contract with the client and a matching JCT subcontract with you.

What decides your money is the subcontract's payment, variation, loss and expense and retention clauses. Just as important are the amendments your main contractor has made to them.

JCT publishes a subcontract to sit under each of its main building contracts. The common forms suit different types of work.

The Standard Building Sub-Contract sits under the Standard Building Contract on larger jobs. The Design and Build Sub-Contract is used where your package includes design. The Intermediate Sub-Contract serves mid-sized jobs and has a version for subcontractors who design. The Short Form of Sub-Contract is intended for simpler packages.

The front pages name the form and its edition, such as 2016 or 2024. Clause numbers change between editions, so read the edition you are signing.

If your package includes design, you may be taking on part of the main contractor's design duty. JCT explains its design and build form in JCT Design and Build Contract 2016: Simply Fair.

Most JCT subcontracts arrive with a schedule of amendments, and that is where risk usually moves to you. Look for changes to the payment dates, notice periods, set-off, delay damages and retention.

For how to push back before you sign, see Can I change the terms of a JCT or NEC subcontract before I sign? What an amended clause means in law is a question for your solicitor.

JCT payment runs on monthly valuation dates. On the unamended main contract, payment falls due 7 days after each valuation date, and the final date for payment is 14 days after that. Your subcontract sets its own periods.

JCT gives its own account in JCT Explains…Interim Payments. On this site, see What is the JCT payment timeline? and JCT Payment Notices and Pay Less Notices. For suspending work, see how JCT clause 4.13 works.

JCT calls a change a Variation. Your main contractor instructs it, and it is valued under the valuation rules, starting from your own rates.

Get every instruction in writing. See how JCT section 5 values variations and how JCT clause 3.14 deals with instructions.

JCT treats time and money separately. A Relevant Event can give you more time, which protects you from delay damages. A Relevant Matter can give you loss and expense: the money a delay or disruption cost you.

One does not bring the other, and each needs its own notice, given promptly. See how JCT clause 4.20 deals with loss and expense and What is a Relevant Matter under JCT?

On a JCT job, retention is held from each payment and usually comes back in two stages. Half comes back at practical completion, and the rest when the defects are made good.

On a subcontract, the release events are the ones your subcontract names. See What practical completion means for your money and how JCT clause 2.38 deals with defects.

Every JCT subcontract gives you the right to adjudicate. For a final decision, it names either arbitration or the courts, depending on what the particulars say.

For how the two main families compare, see JCT or NEC: what the difference means for a subcontractor.

I don't know what my subcontract commits me to. We explain contract risks before signing and turn signed terms into clear actions. See Pre-Signing Contract Review and Post-Signing Contract Review.

I've been underpaid. We value the shortfall and challenge unsupported reductions. See Underpayment Claim.

My variations aren't being paid. We value instructed changes and pursue unpaid variations. See Variation Claim.

Delays and disruption are costing me. We organise delay records and prepare evidenced claims for the cost. See Delay & Disruption Claim.

My retention hasn't been released. We check release conditions and pursue overdue retention. See Retention Claim.