Claims » Variations

Valuation of Variations — Rates, Star Rates, and Reasonable Cost

When a variation is agreed in principle, the next question — often equally contentious — is what it is worth. Variation valuation is not simply measurement and application of contract rates. It requires structured analysis of the pricing mechanism, the character of the varied work, and the conditions under which it is executed.

4 min read · Updated 21/04/2026

In this article

1. Where valuation disputes arise
2. The valuation hierarchy under JCT and FIDIC
3. Practical application — the three-pillar argument
4. Risks and mitigation
5. Conclusion

Key takeaway

The valuation hierarchy under FIDIC Clause 12.3 and JCT Schedule 2 progresses from contract rates, to contract rates with adjustment for different conditions or character, to fair rates and prices. Departure from contract rates requires three things: different character, different conditions, and demonstrable commercial impact. Higher costs alone are not enough.

1. Where valuation disputes arise

The most common disputes in variation valuation arise at the boundary between contract rates and star rates or fair valuation. The contractor argues that the varied work is sufficiently different from the bill description — in character, timing, sequence, or physical conditions — to justify new rates. The employer argues that the contract rates were priced anticipating variations and should apply across a range of similar circumstances.

A related problem arises in lump-sum contracts without detailed bills of quantities. Where the contract is priced against an employer’s requirement, there are no item rates to apply to individual variations. Valuation must proceed on a different basis — typically reasonable cost plus a percentage for overheads and profit — and the parties frequently disagree about what “reasonable” looks like in that context.

2. The valuation hierarchy under JCT and FIDIC

The hierarchy of variation valuation is set out in most standard forms. Under JCT Standard Building Contract 2016, Schedule 2 (Variation Quotation) and Clause 5 establish the following approach:

3. Practical application — the three-pillar argument

For contractors seeking to depart from contract rates, the argument must be built on three pillars:

• Different character — the varied work requires different plant, different labour skills, or a different method.
• Different conditions — the physical or programme conditions differ materially from those prevailing when the rates were priced.
• Commercial impact — the contract rate is demonstrably inadequate for the actual cost of the varied work in those conditions.

Support each pillar with contemporaneous cost records and independent quantity surveying analysis. For employers and their quantity surveyors, the defence is the same structure in reverse: assess the variation against the contract hierarchy, challenge departures by reference to contract conditions and the nature of the work, and resist star-rate claims based on higher cost alone where character and conditions remain similar.

4. Risks and mitigation

For contractors who accept variation instructions without first agreeing the valuation basis, the risk is that final valuation at project end is significantly less than the actual cost incurred. For employers who dispute variation valuations without a clear contractual basis, the risk is that the contract administrator certifies rates the employer later disputes in arbitration — a position that is both expensive to defend and commercially embarrassing.

Mitigation is real-time discipline. Where a significant variation is to be instructed, agree the valuation basis before the instruction is implemented — through a variation quotation procedure, a dayworks arrangement, or a prior rate agreement. Maintain detailed cost records for all varied work as a matter of course. Resolve variation valuations as they occur rather than accumulating them for end-of-project settlement.

5. Conclusion

Variation valuation is a technical exercise with real financial consequences. The hierarchy of applicable rates, derived rates, and fair valuation is the framework — but its application requires commercial judgement, contemporaneous evidence, and a clear understanding of the contract’s pricing mechanism. Star-rate claims that rest on cost alone rarely succeed; those built on the three-pillar structure usually do.

Disputed variation valuations?

We act as consulting experts on variation-valuation disputes under FIDIC, JCT, and bespoke UAE contracts. An early review of the pricing structure and cost records frequently changes the outcome.

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