Daywork is a method of valuing construction work on the basis of the labour, plant and materials actually used, plus tendered percentage additions for overheads, incidentals and profit. It is used where work cannot sensibly be measured or priced in advance: breaking out unforeseen obstructions, working around unrecorded services, opening up and reinstating, or attendance whose extent cannot be known until it is done.
In UK building work the prime cost is normally calculated under the RICS Definition of Prime Cost of Daywork, with plant commonly priced against published schedules; civil engineering has its own equivalents. Under JCT contracts, daywork is the fallback valuation for varied work that cannot properly be valued by measurement, using the rates and percentages carried in the contract documents.
The currency of daywork is the daywork sheet: a dated record of who worked, for how long, with what plant and materials, on what task and where, ideally signed by the supervising party at the time. Signature practice matters. Many sheets are countersigned “for record purposes only”, meaning the signatory confirms the resources were there without accepting that daywork is the right basis of valuation. That still has real value: it puts the facts beyond argument and narrows any dispute to principle.
Unsigned or late sheets are where daywork value goes to die. A sheet produced weeks after the event, with round numbers and no corroboration, invites a discount. A sheet that conflicts with the site diary or with photographs of the work front invites worse, because it discredits the sheets that were accurate.
Corroboration is therefore the whole game. Daily records showing the same operatives, plant and locations as the sheets make a daywork account hard to argue with; photographs of the work as it proceeded do the same. The account that reconciles with the rest of the project record tends to get paid. The one that stands alone tends to get cut.
NEC contracts approach the same problem differently: there is no daywork option as such, and compensation events are assessed on Defined Cost plus the Fee. The label changes but the burden does not, because Defined Cost still has to be evidenced from records of what was actually expended, kept as the work was done.
Construction Metric builds a daily record of labour, plant and progress from the site WhatsApp group, which is exactly the corroboration a daywork account needs: see a sample diary.