JCT Contracts Explained: Choosing the Right Form for Your Development

Most commercial and residential building work in the UK is contracted on a standard form published by the Joint Contracts Tribunal, known as JCT. Using a recognised standard form means both sides start from a familiar, balanced set of terms rather than a bespoke document that nobody has tested. The difficulty for first-time developers is that JCT is a family of contracts, not a single one, and choosing the wrong form is an expensive mistake. This guide explains the forms you are most likely to meet.

The Main JCT Forms

• Minor Works Building Contract: a short, simple form for low-risk work with a clear specification, typically smaller refurbishments and alterations designed by the client's team.

• Intermediate Building Contract: for straightforward projects of moderate size where the client's team provides the design and the contractor may have limited design responsibility for specific elements.

• Standard Building Contract: for larger or more complex schemes designed by the client's team, available with or without bills of quantities or approximate quantities.

• Design and Build Contract: for projects where the contractor takes responsibility for design as well as construction, working to the employer's requirements.

Matching the Form to the Project

As a rule of thumb, the more complex the scheme and the more risk you want allocated in detail, the more substantial the form should be. A modest refurbishment with a full specification may suit Minor Works. A small residential development with a completed design may sit comfortably under the Intermediate form. A scheme where you want one party responsible for design and build usually points to the Design and Build Contract. If you are unsure, an experienced main contractor or a quantity surveyor can advise, though anything with significant value or amendments deserves independent legal advice.

Clauses Worth Understanding Before You Sign

• Contract sum and payment: how and when the contractor is paid, and the notices required under the Construction Act.

• Practical completion and defects: what practical completion means, and how long the contractor remains responsible for putting right defects afterwards.

• Retention: a percentage of each payment held back as security, commonly released in stages, with part usually released at practical completion.

• Liquidated damages: the pre-agreed daily sum payable if the contractor finishes late.

• Extensions of time and variations: how delays and changes are assessed and priced.

• Insurance and warranties: which party insures the works and what collateral warranties funders or purchasers may require.

A Practical Note

Standard forms are only as good as the schedules attached to them. Amendments, the contract particulars and the employer's requirements often matter more than the form itself, so read them as carefully as the main conditions. Berati Construction works under standard JCT arrangements as well as bespoke agreements, and we are happy to talk through the form that suits your scheme before you commit. This article is general information, not legal advice.

To see how contract choice fits into procurement, read our guides to design and build vs traditional contracts and how to de-risk a development scheme. You can also explore our services or get in touch to discuss your project.