What the JCT Minor Works contract is
The Joint Contracts Tribunal (JCT) publishes standard building contracts used across the UK construction industry. The Minor Works Building Contract is its short form for simple work at a fixed lump sum price, where the design is provided by or for the client and a named person (the architect or contract administrator) runs the contract. The current edition is the Minor Works Building Contract 2024 (MW 2024), published in 2024. JCT withdrew the 2016 edition on 31 March 2026; it remains on sale digitally only for a transition period ending 31 December 2026, meant for projects already started or tendered on it. For a new home project in November 2026, use MW 2024.
Offered a 2016 form? Ask why. It may be a builder's old template. JCT recommends the 2024 edition for anything not yet tendered, and after 31 December 2026 blank 2016 forms can no longer be bought. The JCT Home Owner contracts are a separate family; their 2021 versions remain current.
There is a sister form, the Minor Works Building Contract with contractor's design (MWD), for jobs where the builder designs a defined part of the work, such as the steelwork connections, the roof or the heating system.
Lump sum means the builder agrees to do the defined work for a stated total. The total changes only through the mechanisms the contract allows: variations you instruct, provisional sums being spent, and a few events such as some delays caused by you.
When it suits a home project
JCT says Minor Works is suitable where the work is simple, is designed by or for the employer, and does not need bills of quantities or detailed control procedures. For homes, that describes most single-storey extensions, loft conversions and refurbishments that have an architect or surveyor on board.
| Your situation | Usual form | Why |
|---|---|---|
| Architect or surveyor designs and runs the contract | Minor Works (MW) | Designed for a contract administrator to certify payments and completion |
| As above, but the builder designs part of the job | Minor Works with contractor's design (MWD) | Adds the contractor's designed portion and design responsibility |
| You deal directly with the builder, no consultant | Home Owner contract (HO/B) | Plain-English consumer contract, no contract administrator role |
| You have a consultant but want simpler wording | Home Owner contract with consultant (HO/C) | Consumer wording with a consultancy agreement alongside |
| Complex job, bills of quantities, detailed extension of time rules | Intermediate (IC) or Standard (SBC) | Minor Works deliberately leaves these out |
A practical rule: if there is no architect or surveyor to act as contract administrator, Minor Works is the wrong tool. Clauses that say "the Architect/Contract Administrator shall certify" have nobody to operate them. The JCT Home Owner contracts were written for that situation.
What makes up the contract
The printed form is only part of it. The contract documents are usually:
- The Agreement and Contract Particulars: who the parties are, the contract sum, dates, the retention percentage, the rectification period, insurance option and so on. This is where most of the choices are made.
- The Contract Drawings: listed by number and revision.
- The Contract Specification and/or Work Schedules: what materials and standards apply.
- A priced document: the builder's priced schedule, which is used to value variations.
The most common gap: the quote and the drawings say different things, and nobody wrote down which wins. List every drawing and document in the contract, and remove anything the builder priced that you do not want. The builder quotes chapter shows how to line them up.
The clauses that matter, in plain English
Section and clause references below follow MW 2024, which kept the 2016 layout for these topics. Check the edition you are signing.
Starting and finishing (section 2)
The Contract Particulars state a date for commencement and a date for completion. If the builder is delayed by something outside their control, the contract administrator must give a fair extension of time. Minor Works keeps this short: there is no long list of "relevant events" like the bigger JCT forms.
Liquidated damages
You can state a weekly rate the builder pays if they finish late without a valid extension. For homes this is often modest, for example £150 to £500 a week, and it should be a genuine pre-estimate of your loss such as rent for alternative accommodation. Writing "nil" means no damages at all, which is different from leaving it blank. Agree it before signing, not after a delay.
Practical completion
When the work is finished apart from very minor items, the contract administrator certifies practical completion. This date matters more than any other: it stops liquidated damages, starts the rectification period, triggers release of half the retention, and passes insurance and security of the works back to you.
Practical completion has no exact definition in the contract. In practice it means the works are complete for practical purposes, you can use them safely, and any outstanding items are trivial. A missing kitchen or an unsigned building control completion certificate is usually not trivial.
Rectification period
After practical completion the builder must come back and fix defects that appear during the rectification period. The default in Minor Works is 3 months unless you write another period in the Contract Particulars. For a home, 6 or 12 months is common and sensible: it lets a full season of heating, rain or sun expose cracks, leaks and shrinkage. At the end, the contract administrator lists defects, the builder fixes them, and a certificate of making good is issued.
Payment (section 4)
Interim payments are normally made at intervals of not more than one month, based on the value of work properly done, or at agreed stages. Each payment has a due date and a final date for payment. If you intend to pay less than the amount stated, the contract requires a pay less notice before a set deadline giving the amount and the reason. Missing that deadline can mean paying in full and arguing later.
Retention
Unless the Contract Particulars say otherwise, Minor Works holds back 5% of the value of work from interim payments, and that drops to 2.5% at practical completion. The remaining 2.5% is paid with the final certificate after the rectification period and making good. You can change the 5% figure; 3% is common on domestic work. Our payment schedule worksheet shows the money at each stage, and retention and stage payments covers the proposed ban on retentions.
Variations (section 3)
The contract administrator can instruct changes. Each variation is valued, ideally agreed in advance, using the rates in the priced document where they apply. Ask for a price before instructing anything significant.
Provisional sums
Allowances for work not yet defined are adjusted to the actual cost once the work is instructed. Large provisional sums weaken the fixed price. See provisional sums and contingency.
Insurance (section 5)
For work to an existing house, the usual option puts insurance of the existing structure and the new works on the homeowner. Tell your home insurer before work starts, in writing, and get their confirmation. Many standard home policies exclude or limit cover during building works.
Termination (section 6)
Either side can end the contract for specified defaults or insolvency, following a notice procedure. The 2024 edition adds new insolvency grounds and lets most notices go by email, though default and termination notices go by email only if the Contract Particulars say so.
Disputes (section 7)
Adjudication is available. The 2024 edition also builds in a requirement for the parties to work together collaboratively and in good faith, and to try negotiation before formal disputes.
What changed from MW 2016 to MW 2024
The 2024 edition is an update rather than a rewrite. For a homeowner the changes that matter are:
- Most notices can be given by email.
- Updates for the Building Safety Act 2022 duty-holder roles: a new article covers who acts as principal designer and principal contractor under the Building Regulations.
- The collaborative working, sustainability and dispute negotiation provisions are now core terms, not optional extras.
- New insolvency grounds and termination payment rules aligned with the Construction Act.
- Extension of time rules are unchanged. In MWD, the contractor's design duty is reasonable skill and care, never fitness for purpose.
Principal designer and principal contractor are duty-holder roles under the CDM Regulations 2015 and, separately, Part 2A of the Building Regulations. On domestic work where there is more than one contractor, these roles normally pass to the designer and builder rather than you. The contract records who holds them.
| Topic | MW 2016 | MW 2024 |
|---|---|---|
| Status in November 2026 | Withdrawn 31 March 2026, digital sales until 31 December 2026 | Current edition |
| Notices | Mostly by post or hand | Most by email; termination by email only if the Contract Particulars allow |
| Building Safety Act roles | Not covered | Principal designer and principal contractor under the Building Regulations recorded |
| Collaboration and sustainability | Optional supplemental provisions | Core terms |
| Retention and rectification defaults | 5%, 3 months | 5%, 3 months (unchanged; set your own) |
Filling in the Contract Particulars: a checklist
- Correct legal names and addresses of both parties. If the builder is a limited company, use the registered name and number.
- Contract sum, and whether it includes VAT.
- Every drawing and document, by number and revision.
- Commencement and completion dates, and liquidated damages per week.
- Retention percentage (default 5%) and rectification period (default 3 months, consider 6 to 12).
- Interim payment dates or the stage schedule.
- Insurance option, and confirmation from your insurer.
- Named contract administrator.
- Who is principal designer and principal contractor.
- Whether termination notices may go by email.
Watch: the traditional route that Minor Works belongs to
A quantity surveyor explains the traditional route: complete the design, tender it, then run the build under a JCT contract with a contract administrator in the middle. The examples are mostly larger projects, but the same logic applies to a house extension with a smaller team.
Video by Metroun Quantity Surveying. Open it on YouTube. YouTube is contacted only when you press play, through its reduced-tracking youtube-nocookie domain.
Common questions
Can I use JCT Minor Works without an architect?
It is possible to name a surveyor or other professional as contract administrator, but not sensible to name yourself unless you understand the certification duties. Without any consultant, the JCT Home Owner contract (HO/B) fits better.
Does the Construction Act payment regime apply to my home extension?
Contracts with residential occupiers for work on their own home are largely excluded from the Housing Grants, Construction and Regeneration Act 1996. Minor Works still sets out payment notices and dates in its own terms, so they apply because you agreed to them.
Where do I buy the contract?
Directly from JCT, as a hard copy or through JCT On Demand, which lets you fill it in online. Each party should keep a signed copy.
What is the most common JCT contract for home extensions?
Where an architect or surveyor runs the job, Minor Works (MW 2024, or MWD 2024 if the builder designs part). Where you deal with the builder directly, the JCT Home Owner contract. The larger Intermediate and Standard Building Contracts are for bigger, more complex projects.
What is clause 2.17.3 of JCT?
Clause 2.17.3 belongs to the JCT Design and Build Contract, not Minor Works. It lets the parties cap the contractor's liability for loss of use, loss of profit and other consequential loss arising from design faults, at an amount stated in the Contract Particulars. The cap does not apply to work on a dwelling covered by the Defective Premises Act 1972, and it does not affect liquidated damages. For a homeowner it rarely arises; if a builder offers a design and build form with a figure entered there, ask what it means for you.
What can make a building contract void?
In general contract law, a contract can be void or unenforceable if there was no real agreement on essential terms, if its purpose is illegal, or if one party lacked capacity to contract. A contract obtained by misrepresentation or undue pressure can be set aside. With a signed standard form and a clear scope these are unlikely; the more common problem is an informal agreement where nobody can show what was agreed.
Should I get the contract checked?
For a large project or if anyone proposes amendments, a short review by a construction solicitor or your architect is money well spent. Unamended standard forms are much easier to rely on than bespoke terms.
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