Dayworks in Construction: How They're Valued and Agreed

Dayworks construction claims exist because no bill of quantities, however carefully drawn up, can anticipate every eventuality on site. When an instruction covers work that cannot be fairly priced against existing rates, quantities, or a comparable measured item, dayworks becomes the fallback: paying the contractor for the actual time, materials and plant used, plus an agreed allowance for overheads and profit.

That flexibility is exactly why dayworks is one of the most contested areas of commercial management. Because the valuation depends on records rather than pre-agreed rates for a defined quantity of work, disputes over hours, scope, signatures and applicable percentages are common, and they tend to surface at final account stage, long after the memory of who did what has faded.

This guide sets out what dayworks actually means, when it should be used under JCT and NEC contracts, how RICS and CECA schedules price labour, plant and materials, and why contemporaneous daywork sheets are the single most important piece of paper in the whole process. It closes with the practical habits that keep dayworks claims defensible rather than disputed.

Whether you are a quantity surveyor signing sheets on site, a commercial manager reviewing a subcontractor's daywork account, or a project manager trying to understand why your QS is so insistent about same-day sign-off, this article is written as a reference you can return to whenever a daywork instruction lands on your desk.

What Are Dayworks in Construction?

A cost-plus alternative to measured valuation

In most construction contracts, work is valued by measurement: a quantity of a defined item, priced at a rate fixed in the bill of quantities or schedule of rates. Dayworks abandons that approach entirely. Instead, the contractor is paid for the actual resources deployed, the hours worked by each grade of operative, the materials consumed, and the plant employed, priced at agreed rates, with a mark-up added to cover overheads and profit that a measured rate would otherwise already include.

It is, in effect, time-and-materials billing dropped into a lump-sum or measured contract. That makes it useful, because it can price genuinely unforeseeable work, but it also removes the natural discipline of a fixed rate for a fixed quantity, which is precisely why records and verification carry so much weight.

When dayworks should be used, and when it should not

Dayworks is intended for the exception, not the rule. Typical scenarios include unforeseen ground obstructions during excavation, small ad-hoc remedial items with no comparable bill rate, emergency or urgent instructions where there is no time to agree a measured price in advance, and minor variations too fragmented to measure sensibly. It is not intended as a default fallback whenever a contractor and QS cannot agree a rate quickly; using dayworks for work that could reasonably have been measured is itself a common source of argument.

• Unforeseen obstructions or conditions discovered during groundworks
• Instructed variations with no comparable rate in the bill of quantities
• Genuinely urgent or emergency remedial work
• Small, fragmented items uneconomic to measure and price individually

Dayworks Under JCT and NEC Contracts

JCT: dayworks as the valuation rule of last resort

The JCT Standard Building Contract sets out a clear hierarchy for valuing variations: work should be valued by measurement, using bill rates, analogous rates, or fair rates and prices, and only where none of those can be applied fairly is work valued on a daywork basis. Where JCT dayworks does apply, the contract requires vouchers, specifying time spent, workpeople, plant and materials, to be delivered to the contract administrator for verification, typically within a short period, often a week, of the work being carried out. Late or unverified vouchers weaken a contractor's position considerably, since the contract administrator's signature is the main contemporaneous evidence that the resources claimed were actually deployed.

NEC: no dayworks, but a similar cost-based mechanism

NEC contracts deliberately avoid the term "dayworks" altogether. Instead, additional or varied work is valued through the compensation event mechanism, priced using Defined Cost, the actual cost of the people, plant, equipment and materials used, plus the Fee percentage stated in the contract data to cover overheads and profit. Conceptually this achieves much the same outcome as cost-plus dayworks, but it is governed by NEC's own quotation and assessment procedures rather than a discrete daywork schedule, and disputes tend to centre on what counts as Defined Cost rather than on daywork rates as such.

Pricing Dayworks: RICS, CECA and the Daywork Schedules

Rather than negotiate labour, plant and material rates from scratch on every job, most UK construction contracts price dayworks against published schedules. For building work, the relevant document is the RICS and Construction Confederation's Definition of Prime Cost of Daywork Carried Out Under a Building Contract; for civil engineering, the equivalent is the CECA (formerly FCEC) Schedules of Dayworks Carried Out Incidental to Contract Work. Both set out standard labour classifications, definitions of what counts as prime cost, and the basis for percentage additions covering supervision, overheads and profit.

What a dayworks schedule actually prices

A schedule of dayworks lists the classifications of labour by trade and grade, together with all-in hourly rates or a method for calculating them, standard percentage additions for incidental costs, and the basis for pricing plant, either at published plant-hire schedule rates or actual invoiced cost, and materials, usually at net invoice cost plus a percentage for handling and storage. The table below shows the typical structure a QS would expect to see in an agreed schedule.

Cost-Plus Rates vs All-Inclusive Daywork Rates

In practice, dayworks is priced one of two ways. Cost-plus valuation reimburses the contractor's actual, evidenced cost of labour, materials and plant, with an agreed percentage added on top for overheads and profit. All-inclusive rates, by contrast, use pre-agreed lump-sum hourly rates, tendered at contract award or taken from the RICS/CECA schedule, that already bundle in an allowance for overheads and profit, so no separate percentage addition is needed. Which method applies should be fixed in the contract, not decided after the work is done.

Contemporaneous Dayworks Sheets: Why Records Have to Be Made on the Day

Dayworks lives or dies on paperwork. A daywork sheet, sometimes called a voucher or ticket, records the operatives present, their trade grade, the hours worked, the plant used, and the materials consumed against a specific instruction, on the day the work happens. The site supervisor completes the sheet, and the client's representative, the contract administrator, project manager, or site QS, reviews and signs it before leaving site, ideally the same day or at worst within the period the contract specifies.

It is worth being precise about what a signature actually confirms. Signing a daywork sheet is evidence that the stated labour, plant and materials were present and engaged on the instructed work; it is not, on its own, an admission that the work was correctly classified as daywork, that the rates claimed are agreed, or that the total account is accepted. Experienced QSs routinely annotate sheets "signed for record purposes only, entitlement and valuation reserved" precisely to keep that distinction clear, and to avoid a signature being read later as acceptance of the whole claim.

Where sheets are not submitted daily, or where signatures are missing altogether, the QS loses the ability to challenge hours or allocation with any confidence months later. Cross-checking sheets weekly against the site diary, labour allocation sheets and material delivery tickets closes that gap and gives both sides a running, agreed total rather than a disputed lump sum at final account stage.

Common Dayworks Disputes and Why They Happen

Dayworks disputes rarely come down to the published rates themselves; the schedules are well established and rarely contested in isolation. They come down to the records, the instruction, and the timing of the challenge. The chart below sets out the themes that recur most often in commercial disputes over dayworks accounts.

Best Practice for QSs Agreeing Dayworks

Good dayworks administration is mostly discipline, not technical complexity. A few habits, applied consistently, prevent most of the disputes described above from ever reaching final account stage.

• Confirm daywork status in writing before or immediately after the instruction is given, referencing the applicable schedule and percentage additions
• Insist on same-day or next-day submission of daywork sheets, never allow them to accumulate unsigned
• Sign sheets promptly but clearly for record purposes only, reserving entitlement and valuation
• Cross-check hours and plant against the site diary, labour returns and delivery tickets before signing
• Keep a running log of agreed daywork totals throughout the project rather than reconciling everything at final account
• Push back firmly on any attempt to reclassify measured or varied work as daywork after the event

Used properly, dayworks is a sensible, well-established tool for pricing genuinely unmeasurable work. Used carelessly, without contemporaneous records, it becomes one of the most reliably contentious items on any final account. The difference between the two outcomes is almost always down to how quickly, and how consistently, the paperwork was handled on the day.

Frequently Asked Questions

What are dayworks in construction?

Dayworks is a method of valuing instructed construction work on a cost-plus, time-and-materials basis, pricing the actual labour, plant and materials used plus a mark-up for overheads and profit, rather than by measured bill rates. It is used when work genuinely cannot be fairly valued any other way.

When should dayworks be used instead of measured rates?

Dayworks should be reserved for work with no comparable rate in the bill of quantities, unforeseen obstructions, genuine emergencies, or small fragmented items uneconomic to measure. It should not be used as a default whenever agreeing a rate proves inconvenient.

What is the RICS definition of daywork?

RICS's New Rules of Measurement (NRM2) defines daywork as valuing work based on time spent by the contractor's workpeople, the materials used, and the plant employed. Pricing is commonly based on the RICS and Construction Confederation's Definition of Prime Cost of Daywork for building work, or the equivalent CECA schedule for civil engineering.

Does signing a daywork sheet mean the claim is agreed?

No. Signing a daywork sheet is evidence that the stated labour, plant and materials were present and engaged on the instructed work on that day. It is not, by itself, an admission that the work was correctly classified as daywork or that the rates and total account are accepted.

How does NEC deal with dayworks?

NEC contracts do not use the term dayworks. Extra or varied work is instead valued through the compensation event mechanism, priced using Defined Cost, the actual cost of people, plant and materials used, plus the Fee percentage stated in the contract data.

What is the difference between cost-plus and all-inclusive daywork rates?

Cost-plus reimburses actual, evidenced cost of labour, materials and plant plus a separately agreed overhead and profit percentage. All-inclusive rates are pre-agreed hourly rates, from a schedule or tender, that already bundle overheads and profit into the figure.

Why do dayworks so often lead to commercial disputes?

Because valuation depends on records rather than a pre-fixed price for a fixed quantity, disputes commonly arise from unsigned or late daywork sheets, disagreement over whether the work should have been measured, disputed hours, and retrospective claims raised only at final account stage.

Final Thoughts

Dayworks construction claims are not inherently risky; they are a well-established, RICS and CECA-backed mechanism for pricing work that cannot fairly be measured any other way. The risk sits entirely in how the paperwork is handled: same-day sheets, clear instructions confirming daywork status, and prompt, carefully worded sign-off keep a daywork account defensible from instruction through to final account. Treat dayworks as an exception method requiring daily discipline, not a convenient shortcut, and most of the disputes covered in this guide simply never arise.

Want the full picture? Want to Get Variations and Final Accounts Right First Time?

Read our related guides on valuing variations under JCT and NEC, understanding compensation events, and building a final account that survives scrutiny, so your dayworks claims are backed by a full commercial process, not just a signed sheet.