Are verbal site instructions binding under JCT contracts? No. Under standard JCT subcontracts, verbal instructions have no immediate legal standing. For an oral instruction to become enforceable, the subcontractor must confirm it in writing within 7 days under Clause 3.14. If the contractor does not dissent in writing within 7 days, it becomes a binding written variation.
Carrying out extra work on site because a site manager told you to “just get on with it” is the fastest way to lose money under a JCT subcontract.
Almost every trade contractor has heard the phrase: “Do it now, mate, and we’ll sort the paperwork on Friday.” But when valuation time comes around, the commercial team rejects your variation claim because you do not have a formal written instruction. If you carry out variations without confirming them in writing, you end up footing the bill for materials, plant, and labour yourself.
Below, I break down how JCT Clause 3.14 works, why verbal orders fail, and how to protect your cash flow on site.
The JCT Demystifier: Variation Instructions & Notices
Technical Authority: JCT Subcontract (SBCSub and DBSub) Clause 3.14 (Architect/Contractor Instructions) and Clause 5.2 (Valuation of Subcontract Variations).
Plain English Translation: A variation is any change to the agreed design, scope, quantity, or working sequence set out in your subcontract. Under standard JCT rules, you are not legally obliged to carry out any altered work until you receive a formal written instruction, or submit your own Confirmation of Verbal Instruction (CVI) that remains unchallenged for 7 days.
Loss Aversion & Financial Risk: If you perform varied work without a written instruction or fail to issue a formal CVI notice within the strict 7-day contract timescale, the main contractor has the legal right to value that work at £0.00. You absorb the extra labour, plant hire, and supplier invoices directly, causing severe revenue loss.
3 Non-Negotiable Rules for Site Variations
- Always Issue a Confirmation of Verbal Instruction (CVI): Never start extra work based on a handshake or a phone call. Send an email immediately confirming the verbal instruction, the specific scope of work, the location, and the date it was ordered.
- Watch for the 7-Day Pushback Window: Under standard JCT provisions, if the contractor does not disagree with your written CVI within 7 days, it becomes a binding written instruction. Keep full digital proof of sending.
- Spot Bespoke Deferred Payment Clauses: Look out for bespoke schedules that force you to execute variations immediately but state that valuation and payment will only take place at the final account stage.
Frequently Asked Questions About JCT Site Instructions
What is a CVI in UK construction?
A CVI stands for Confirmation of Verbal Instruction. It is a formal written notice issued by a subcontractor to confirm an oral site direction, activating the 7-day confirmation procedure under JCT Clause 3.14.
Can a main contractor refuse to pay for verbal instructions?
Yes. If the subcontract requires written instructions and the subcontractor fails to serve written confirmation within 7 days under Clause 3.14, the contractor’s commercial team can lawfully value the work at zero in monthly valuations.
How long does a main contractor have to reject a CVI?
Under standard unamended JCT subcontracts, the main contractor has exactly 7 days from receipt of your written CVI to issue written notice of dissent. If they do not object within 7 days, the instruction is confirmed as a binding written variation.