JCT Contracts and Estimating Overview for UK Builders.
JCT (Joint Contracts Tribunal) standard form contracts govern the rights and obligations of UK construction parties. Estimators must review the chosen JCT contract form to allow for liquidated damages, retention percentages, payment terms, and risk allocation.
Authored by Alexandr Vreme | Reviewed by Maksym Vasylkov
Published — Next review
Who this guide is for
Main contractors, trade contractors, and commercial managers. Scope: UK-wide.
Common JCT Contract Forms for Small/Medium Works
- JCT Minor Works Building Contract (MW/MWD): Suitable for simple, straightforward projects up to approx. £500k without complex specialist subcontracts.
- JCT Intermediate Building Contract (IC/ICD): For medium-sized projects requiring detailed mechanical/electrical subcontractor packages or sectional completion.
- JCT Design and Build (DB): Contractor carries design responsibility for portion or all of the works.
Estimating Considerations
Contract clauses directly impact pricing: retention requirements (e.g. 5%), payment terms (e.g. 14 or 28 days), and liquidated damages for delayed completion (£/week).
Miniature Example
A contractor pricing a JCT Minor Works agreement notes a £500/week liquidated damages clause. The estimator adds 5 working days of risk contingency to the proposed construction duration.
Primary Sources & Further Reading
Official reference sources: GOV.UK Building Regulations, Legislation.gov.uk, and HSE CDM 2015 Guidance.
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