Definition

A variation negotiation is the process by which the employer's quantity surveyor and the contractor's commercial manager agree the value of work falling outside the original contract scope. Under most standard form contracts, including the JCT suite and the NEC suite, the employer has the right to instruct variations and the contractor has the corresponding right to fair payment. The parties' surveyors are responsible for agreeing that valuation, or referring disagreement to the contract's dispute resolution mechanism.

Why this matters for Communication and Negotiation

  • Variation valuation and negotiation is a core task for quantity surveyors; at Level 2, assessors expect you to describe the contractual basis, valuation approach and outcome.
  • Unresolved variations are a leading cause of cost overrun, programme delay and formal dispute on construction projects.
  • Rule 3 (Service) requires the surveyor to reach a fair, evidenced valuation without unnecessary delay; Rule 1 (Honesty and Integrity) requires both parties to negotiate on genuine evidence.

Key principles

Establish contractual entitlement first

Before engaging with a variation claim, confirm whether the instruction was validly issued, whether a written variation order was raised, and whether the work genuinely falls outside the original scope. Valuing a variation before establishing entitlement risks conceding a claim that has no contractual basis.

Prepare a detailed assessment

Analyse the contractor's submission with the same rigour applied to the original tender: check labour, plant and material rates against the contract schedule of rates or market rates, and verify time-related costs against the actual period of disruption. Where no contract rate applies, derive a fair rate using the relevant contract clause. Every disagreement must be supported by a counter-calculation, not merely a percentage reduction.

Conduct the negotiation with discipline

Share the employer's assessment in writing before the meeting. Work through the claim item by item, agreeing where the contractor's evidence is credible and challenging where it is not. Use open questions to understand disputed figures and confirm agreed items in writing after each meeting. Avoid agreeing a global reduction without resolving the individual components.

Document and close the agreement

Confirm the settlement in writing, issue a formal variation account, notify the client of the agreed value, and update the financial statement. If items cannot be agreed, follow the contract's escalation procedure promptly.

Relevant RICS guidance and legislation

  • RICS Rules of Conduct (effective 2 February 2022) — Rule 1 (Honesty and Integrity) and Rule 3 (Service) govern the fairness and quality of variation valuations.
  • JCT Standard Building Contract — clause 5 sets the mechanism for instructing and valuing variations.
  • NEC4 Engineering and Construction Contract — compensation events manage changes; early warning obligations impose specific communication duties.
  • Housing Grants, Construction and Regeneration Act 1996 — gives parties the right to adjudication at any time, defining the BATNA if negotiations fail.

Ethics and Rules of Conduct angle

Rule 1 (Honesty and Integrity) requires quantity surveyors on both sides to deal in genuine figures: inflating a claim or applying an arbitrary percentage reduction without analysis both fail this standard. Rule 3 (Service) requires the employer's surveyor to reach a fair settlement efficiently; deliberately delaying agreement to erode the contractor's cash flow is as much a conduct breach as accepting an inflated claim.

APC-style Q&As

Q (Level 1)What is a variation under a JCT contract and how is it valued?

A variation is any change to the works instructed by the architect or contract administrator that falls outside the original scope. Under the JCT Standard Building Contract, variations are valued using the schedule of rates where applicable; where no applicable rate exists, the surveyor derives a fair rate from similar work or market rates. Time-related and disruption costs may also be recoverable where the variation caused prolongation or loss of productivity.

Q (Level 1)What is adjudication and when would a quantity surveyor use it in a variation dispute?

Adjudication is a statutory dispute resolution process under the Housing Grants, Construction and Regeneration Act 1996, giving any party the right to refer a dispute to an adjudicator at any time. The decision is temporarily binding. In a variation dispute, adjudication is the BATNA if negotiation fails, typically delivering a decision within 28 days of the adjudicator's appointment.

Q (Level 2)A contractor submits a variation claim of £150,000. You assess entitlement at £95,000. How do you structure the negotiation?

(example) I would share my detailed assessment in writing before the meeting, setting out item by item where I agree with the contractor's figures and where I differ, with reasons. At the meeting I would work through the schedule systematically, agreeing items where the evidence is credible and seeking clarification on disputed items. I would avoid discussing a global figure until all individual components are resolved. The aggregate of agreed items then forms the settlement without either party making an unprincipled concession. Where the contractor disputes my rates, I would invite further evidence (quotations, invoices) before reconsidering.

Q (Level 2)Why is it important to establish contractual entitlement before discussing the value of a variation claim?

Discussing value before entitlement signals that entitlement is not in dispute and concedes the claim is payable in principle. If the instruction was not formally issued, or the work was within the original scope, discussing value may create an implied agreement to pay. The correct sequence is to confirm valid instruction and genuine additional scope before any valuation discussion begins.

Q (Level 3)You act as QS for a developer on a commercial fit-out. The contractor submits a loss and expense claim of £220,000 citing employer-caused critical path delay. Your analysis shows delay is partly the employer's responsibility and partly concurrent with contractor-caused delays. How do you approach the negotiation?

Under JCT contracts, the employer must grant extension of time for employer-caused delay even where concurrent contractor delay exists, but loss and expense entitlement is more limited where the contractor contributed to the delay. I would prepare a delay analysis mapping each alleged employer event against the programme, then calculate loss and expense only for employer-caused, non-concurrent delays. This would produce an assessed figure substantially below the claim. I would present the analysis in a structured meeting, inviting the contractor to challenge it with their own programme evidence. For periods of genuinely uncertain concurrency, I would treat quantum as a negotiating point and consider a proportional allocation. Throughout, the principle is fair compensation for employer-caused delay, consistent with Rule 1 of the RICS Rules of Conduct.