Variation orders and daywork sheets: how subcontractors get changes paid (UK)

A variation order is the written instruction that changes the work you priced: something added, taken out, swapped or done differently. Get it in writing, record the cost as you go, and apply for it on time, and the extra work gets paid. Miss any of the three and it usually doesn't.

This guide is written for UK subcontractors and specialist contractors: what a variation order is, what to do when you're told to change something on site, how variations and dayworks are valued, what a daywork sheet must show, and how to keep a simple register so nothing you've done for free slips through the next application for payment.

General information for England and Wales, not legal advice. Your own contract and its amendments decide who can instruct a change, how it's valued and what notices you must give.

A variation order (VO) is a written instruction that changes the scope of the works in a construction contract. It can add work, omit work, change the materials or specification, or change how the work is done: the sequence, working hours, access or the space you've got to work in.

The name depends on the contract. UK contracts usually say variation or instruction; American ones say change order. JCT contracts call them Variations and deal with them through the contract administrator's (or the contractor's, on a sub-contract) instructions. NEC contracts don't use the word at all: a change to the Scope is a compensation event, with its own notice and quotation process.

What matters is less the name than three facts: who is allowed to instruct the change under your contract, how it must be instructed (almost always in writing), and how it will be valued. If you're on a JCT sub-contract, our guide to JCT contracts shows where those rules sit.

A variation is a change to what you agreed to do. Typical examples on a subcontract package:

• Additions: an extra run of partitions, another floor of first fix, extra openings to form.
• Omissions: part of your package taken out and given to someone else.
• Substitutions: a different board, block, fixing or finish to the one you priced.
• Changed conditions: working out of sequence, night or weekend working, restricted access, returning to an area you'd already finished.

What usually isn't a variation: putting right your own defective work, work that was in your price but you missed when pricing, and anything the contract says is at your risk. A missed item in your own tender is an estimating problem, not a variation, however strongly it feels like extra work.

Usually not, if the instruction is valid. Most standard forms oblige you to comply with instructions the contract allows, and to be paid for them through the valuation rules. There are limited exceptions, such as a reasonable objection to some instructions about access, working hours or the space you can use, and you can refuse an instruction that goes beyond what the contract permits. Those are points to raise in writing, straight away, not reasons to down tools.

The practical rule is simpler: don't start changed work on a verbal instruction. If the site manager asks you to do something different, ask for it in writing. A short email or a signed site instruction is enough to start with. If they won't put it in writing, confirm it yourself ("As instructed by you on site today, we will…") and keep the email. Under many contracts, a confirmed verbal instruction counts once it's confirmed in writing; an unconfirmed one is the easiest thing in construction to refuse to pay.

Contracts set a valuation ladder. The detail varies, but the order is broadly the same:

1. An agreed price before you start. Some JCT forms have a formal variation quotation route; on most subcontracts it's simply a priced quote accepted in writing. This is the strongest position you can be in.
2. Your contract rates, where the varied work is similar to work you priced, under similar conditions.
3. Rates adjusted from your contract rates, where it's similar work under different conditions.
4. A fair valuation where nothing in your price fits.
5. Daywork, where the work can't sensibly be measured: the actual labour, materials and plant used, plus the percentage additions in your contract.

Daywork feels safest on site, because you record what you actually spent. In practice it's the weakest route: every sheet can be argued, and an unsigned one often isn't paid at all. Price the change when you can, and keep dayworks for genuinely unmeasurable work.

Omissions cut both ways. If a large part of your package is omitted, the loss of the overheads and profit you'd built into that work may itself be worth raising when the omission is valued.

A daywork sheet is the site record of the labour, materials and plant used on work being paid at daywork rates. Signed by the main contractor's representative, it's your evidence when the variation is valued. Unsigned, it's your word against theirs.

Each sheet should show:

• The instruction it relates to: the VO or site instruction number and date. A daywork sheet with no instruction behind it is the first one to be rejected.
• Date and exact location of the work (level, grid line, room).
• Labour: each operative's name, trade and hours, day by day.
• Materials: description and quantity, with delivery notes or invoices to back them up.
• Plant: what was used and for how long.
• A description of the work that someone who wasn't there would understand.
• Signatures: yours and the main contractor's representative, with names printed.

The site sheet records quantities; the money is worked out afterwards. Labour is priced at the contract's daywork rates (often the prime cost of labour as defined by the RICS Definition of Prime Cost of Daywork carried out under a Building Contract, plus the percentage addition you tendered), and materials and plant get their own percentages. Check which definition and percentages your contract names: they decide what the sheet is worth.

Many subcontracts set a short window, often around a week, for daywork sheets to be submitted for signing. Miss it and the main contractor may refuse to consider the sheet. Even where there's no deadline, a sheet presented a month later is far easier to dispute: the supervisor who saw the work may have moved on, and nobody remembers who was on site that Tuesday.

A routine that works:

1. Your supervisor fills the sheet in on the day, on paper or on a phone.
2. It goes to the main contractor's site manager by Friday for signature, with a photo of the work.
3. Signed or not, it goes into the office the same week and onto the register (below), marked signed or submitted, unsigned.
4. Unsigned sheets get chased in writing. A signature confirms the resources were used; it isn't always agreement that the work is a variation, so keep the instruction with it.

The reason variations go unpaid is rarely a legal one. It's that nobody has a single list of what was instructed, what it's worth and whether it's been applied for. A variation register fixes that. One row per variation or daywork sheet, updated weekly:

Check the register before every application for payment: anything instructed but not yet applied for goes in. Then compare the payment notice against it: anything you claimed that was valued at nil or cut back is a conversation to have now, and if a pay less notice arrives, you'll know exactly which items it's knocking off. The same list feeds your monthly cost value reconciliation, where unagreed variations are usually the biggest judgement call in the forecast.

• Verbal instructions never confirmed. The work was done; nothing proves it was asked for.
• Daywork sheets never signed, or signed but never priced and applied for.
• Changes priced months later, by someone who wasn't on site, from memory.
• Variations agreed but never invoiced because they weren't on the application.
• Final account surprises: a dozen small changes nobody tracked, rolled into one argument at the end of the job, when you have least leverage.

None of these is solved by better contract wording. They're solved by the same small routine every week: instruction in writing, sheet signed, row on the register, item on the application. Your rights to be paid on time sit in the Construction Act; the register is how you use them.