Variations
What percentage goes on labour, plant and materials?
Whatever number you were hoping for, it is not on this page, because it is not in any statute or standard table. It is in your contract particulars, it was fixed the day you tendered, and there are three of them doing three different jobs.
QScope Team·20 March 2026·4 min read
“What do people normally add on dayworks?” is the wrong question, and the right one pays better: what do my contract particulars say, and what does each percentage have to cover?
Three percentages, three jobs
Daywork provisions carry separate additions for labour, for plant and for materials, because the three bases carry different costs:
- Labour: the addition covers supervision, small tools, statutory costs above the base rate, overheads and profit. It is the biggest number of the three for a reason.
- Plant: covers the cost of having, moving and standing the kit beyond the hire rate itself.
- Materials: covers procurement, handling, waste and the money tied up between buying and being paid.
They are fixed at tender in your contract particulars, which makes them one more of the numbers worth reading before you price, alongside the four payment periods. A percentage that felt generous in a busy year is the same percentage in a thin one.
The base matters more than the number
Where the contract adopts the RICS definition of prime cost of daywork, that document decides what is already inside the base before your percentage goes on: what the labour rate includes, how plant is costed, what counts as a material. A percentage applied to the wrong base is wrong twice: once in the maths, and once in the argument you then have about it.
The blended-rate mistake
One flat percentage across labour, plant and materials looks simpler and quietly rewrites your contract. Blend and you almost always dilute the labour addition, which is where your real overhead sits, on the item that dominates most daywork sheets. Keep three lines on the sheet, three additions, and let the arithmetic be checkable.
On a domestic job
No contract particulars, no standard form, so write your own three into the quote: hourly rate and what it includes, plant basis, materials at cost plus your stated addition. On a thin domestic contract that one paragraph is the entire daywork mechanism, and it only protects you if it exists before the messy work starts.
What to do this week
1. Copy the three percentages from the particulars of every live job onto one page, next to the payment periods.
2. Check the base definition your contract adopts before pricing the next sheet against it.
3. Keep the three lines separate on every sheet, and price the sheets weekly, not at the account. When and whether to use dayworks at all is the previous page.