JCT Contracts Explained: The Types of JCT Contract and Which One to Use

What a JCT contract is

The Joint Contracts Tribunal publishes standard forms of building contract. The parties choose a form and complete it for the project, instead of drafting a contract from nothing.

Each form has three parts. The agreement, or articles, names the parties and the price. The conditions are JCT's standard text on design, time, payment, insurance and termination. The contract particulars hold the project's own settings: dates, damages for delay, retention and the defects period.

JCT launched its 2024 edition with Design and Build on 17 April 2024 and has issued the other families since. The table in the next section shows where each form stands on JCT's own pages, checked on 29 October 2026.

Every JCT form is also written to meet the Construction Act, the Housing Grants, Construction and Regeneration Act 1996. It sets minimum rules on payment and adjudication for construction contracts. We set them out in the last section.

Types of JCT contract compared

JCT publishes more than a dozen families. Most commercial work uses five of them. The table gives the use of each form and its 2024 status, as JCT lists it.

Value limits and the pre-construction agreement

JCT's own pages give no value limit for Minor Works or Intermediate. Scope and complexity decide, as the next section shows. The pre-construction agreement has its own guide: pre-construction services agreement.

If your form is not in this table, or is heavily amended, a construction company in London can price it as written. Send us the form, the amendments and the drawings.

How to choose the right JCT contract

JCT publishes a guide to selecting a main contract. Its flowchart dates from the 2016 edition, and the 2024 forms keep the same family names. These are its questions, in a working order.

1. Is the work to your own home? JCT's Home Owner contracts cover a dwelling the client occupies or will occupy. HO/B is for work with no consultant overseeing it, HO/C and HO/CA for work with one.
2. Do you want the contractor to employ works contractors under your direction? That is the management route: the Management Building Contract, or Construction Management where you appoint the trade contractors yourself.
3. Will the contractor complete the design? If so, the route ends at the JCT Design and Build Contract. For small jobs there are contractor's design versions: MWD and ICD.
4. Is the design fully developed, with detailed documents? Traditional forms assume it is. Do you need a bill of quantities? Then choose the Standard Building Contract with Quantities. If the work is to be measured afterwards, choose approximate quantities.
5. Is the work complex, or heavy in building services? JCT's guide then points to the Standard Building Contract. If not, and detailed procedures or named sub-contractors are needed, it points to Intermediate. If neither applies, it points to Minor Works.
6. Who will administer the contract? Traditional forms expect a consultant, such as an architect or contract administrator. Repair and Maintenance is written for employers who need none.

When the design is not ready

JCT's guide shows the pre-construction agreement can sit in front of the Standard Building, Intermediate, Design and Build and Major Project contracts. The contractor then helps finish the design before the price is fixed.

Choosing a form is also choosing a procurement route. Our guide to design and build vs traditional procurement covers that choice. If no price can be fixed yet, the open-book alternative is in our guide to the cost plus contract.

We build mainly as a design and build main contractor. At Portsoken House in Aldgate our in-house team designed 1,550 m² of offices. We built them in seven months, around tenants who stayed in the building.

JCT Minor Works and Intermediate contracts

These two are the forms people search for most. JCT sets no value limit for either, so the test is scope: how simple the work is, and how complete the client's design information is.

Both forms leave the client's design with the client. In MWD and ICD, the contractor takes a defined designed portion. That is a smaller step than a full design and build contract.

A job that looks simple on paper can still be services-heavy. A fit-out with new mechanical plant, or a refurbishment that needs named specialists, may belong under Intermediate or the Standard Building Contract. If the drawings are still moving, none of these forms is a good fit yet.

JCT or NEC: the difference for a client

NEC is a separate family of contracts. Its NEC4 Engineering and Construction Contract (ECC) is written for engineering, building and construction work. The table sets it next to JCT in plain terms.

Neither is better. Use the form your funder, adviser or public client requires, and one you have a team to administer. The client-side role is explained in our guide to the employer's agent.

Before you sign a JCT contract

Read the contract particulars first. They hold the dates, the damages for delay, the retention percentage, the defects period and the insurance options. Both sides complete them, so they are the part you can negotiate.

Then read the amendments. Ask who drafted them and what each one moves. A contractor that accepts every amendment without changing its price has either not read them or plans to recover the cost in claims.

The payment rules to check

The Construction Act sets the payment minimum for a construction contract. A contract with a residential occupier is excluded. These are the points to check.

1. Payment cycle. The contract needs an adequate mechanism for what is due and when, and a final date for payment. Payment by instalments is a right unless the work will take under 45 days.
2. Payment notice. The payer, or the payee, gives it no later than five days after the payment due date.
3. Pay less notice. A payer who wants to pay less gives notice before the final date for payment. The notice period is the one the parties agree, or the Scheme for Construction Contracts sets.
4. Adjudication. Either party can give notice at any time. The adjudicator then decides within 28 days of referral, unless the time is extended.

Retention, variations and the CDM roles

Two other documents sit alongside the contract. Retention in construction explains the money held back and when it is released. Variations in construction contracts explains how changes are instructed and valued.

Where more than one contractor will work on the project, the client must appoint a principal designer and a principal contractor. It must do so in writing, before the construction phase begins. Our guide to principal contractor vs main contractor sets out who holds each role.

Use this list before you sign. If you want a second pair of eyes on the form and the drawings, get a free pre-construction review. Send them together. Already have a quote? Send it to us. We'll beat it.