What are preliminaries, and how do you price them?

The test is whether the cost can be attributed to a measured item. Bricklaying labour belongs to the brickwork. The site manager who supervises the bricklayer, the welfare unit they use and the scaffold they stand on belong to prelims.

• Management and staff. site manager, agent, engineer, quantity surveyor, first aider. Usually the largest single line.
• Site accommodation and welfare. cabins, drying room, toilets, canteen, and the CDM welfare requirements that are not optional.
• Temporary works. scaffolding, propping, hoardings, temporary roads, edge protection.
• Plant and equipment. crane, hoist, telehandler, generators, small plant not priced in the rates.
• Utilities. temporary power, water, lighting, and the standing charges nobody remembers.
• Security. fencing, gates, cameras, and out-of-hours cover.
• Insurance and bonds. contract works insurance, performance bond, third-party cover.
• Statutory and testing. building control fees, commissioning, testing, and the as-built and O&M documentation required at handover.
• Cleaning and waste. skips, wait-and-load, final clean.

Because it decides who pays for a delay. Split every prelim into the part incurred once and the part incurred every week, and the two behave completely differently when the programme moves.

A four-week extension costs you four weeks of every time-related prelim. If they were priced as a percentage of the works, there is no rate to claim them at, and the money comes out of the margin.

This is also what makes a prolongation claim arguable rather than hopeful. If the tender shows the site manager at a weekly rate, an extension of time has an obvious value. If prelims were a single lump labelled "prelims 12%", the claim starts with a fight about what the lump contained.

1. 01Start from the programme. Prelims are a function of duration. Without a programme you are guessing at the largest time-related costs on the job.
2. 02List the resources the programme needs. Who is on site, for how many weeks, and what plant and accommodation they require.
3. 03Price each as fixed or weekly. A weekly rate for anything that runs, a one-off for anything that happens once.
4. 04Add the statutory and one-off items. Insurance, bonds, building control, testing, commissioning, final clean.
5. 05Check the percentage afterwards, as a sense test. If the total lands at 4% or 25% of the works, something is wrong, but the percentage is the check, never the method.

NoteThe percentage is a sense check and nothing more. Working backwards from "prelims are usually 12%" produces a number that cannot be defended in a valuation, cannot be claimed against in an extension, and is wrong on any job that is unusually short, constrained or remote.

Usually through the interim valuations, and usually in proportion to time elapsed rather than work completed, which is the right treatment, because that is how the cost is actually incurred. A job 30% through its programme has spent roughly 30% of its time-related prelims regardless of how much of the measured work is done.

That distinction is worth being explicit about in the payment application. A valuation that recovers prelims against measured progress will under-recover on any job that starts slowly, which is most of them, groundworks and enabling works consume programme without producing much valuable measured work.

Front-loading the fixed items is legitimate and expected: the scaffold really was erected in week one and really was paid for in week one.

NRM2 (the RICS New Rules of Measurement for detailed measurement) sets out prelims in Section 2, splitting them into employer-provided items and contractor-provided ones, and requiring the fixed and time-related division this article keeps returning to. It replaced SMM7, which many older bills still follow.

Following NRM2 is not compulsory on a private job, but it gives a structure every quantity surveyor recognises, which matters at valuation and matters more at final account. A bill of prelims that follows the standard is easier to agree than one invented for the occasion.