Valuations
What are preliminaries, and how do I price them into a job?
Ask what the blockwork costs and every builder has a number. Ask what it costs per week just to HAVE the site, the scaffold standing, the welfare cabin, the skips turning, yourself supervising, and most small firms have never added it up. That unadded number is the preliminaries, and jobs bleed through it.
QScope Team·24 April 2026·5 min read
Preliminaries (prelims) are everything the job consumes that is not the permanent work: setting up and running the site, managing it, and clearing it away. The professional bills give them their own section at the front, and the reason is not tidiness, it is that prelims behave differently from measured work: most of them are driven by time, not quantity, and that difference is where the money hides.
Build the list, in three piles
- One-off setup and removal: site establishment, hoarding or fencing, temporary services connections, the scaffold’s erection and strike, signage, the final clean.
- Time-related running costs, the dangerous pile: supervision (your own hours managing, priced at true labour cost), scaffold hire per week, welfare and toilet hire, skips, site power and water, small plant, insurance, protection materials. Price each as a rate per week times the programme, visibly, because that arithmetic is what you will need back when the programme moves.
- Job-specific items the checklist finds: road permits and parking, crane or lift days, temporary works, drying out, security. Different every job, forgotten every job, the take-off route should end with a prelims sweep.
Why the weekly build-up is worth the effort
Because time moves, and smeared prelims cannot follow it. A job priced with prelims hidden in the rates has no answer when the programme stretches: the extra six weeks of scaffold and supervision are real costs with no home. A job with prelims built up weekly has the number ready-made: when the delay is the client’s, the prelims-per-week figure is the backbone of the money side of an extension of time, and when a provisional sum firms up into three extra weeks of work, the time cost prices itself. It also keeps your rates honest: measured rates carrying secret prelims look uncompetitive against anyone pricing cleanly, and win or lose on the wrong number.
On a homeowner job, say it in their language
A consumer quote does not need the word preliminaries, but it needs the substance, and stating it plainly reads as competence, not padding: “Site setup, scaffold for the duration, welfare, skips and site management: £X”. The alternative, hiding it, produces the classic domestic argument where the client compares your honest total against a competitor’s bare-rates number and never learns the difference until the extras start. As everywhere on domestic work, the quote is the whole framework (section 106), so what the quote says is what you have.
What to do this week
1. Build your standard prelims checklist, the three piles, from your last three jobs’ actual costs, once.
2. Work out your real weekly running rate, supervision included at true cost, and keep it current: it is the single most reused number in your estimating.
3. Restructure the next quote with prelims as their own visible section, priced as setup plus weeks times rate.
Where the information stops
What proportion of contract value prelims “should” be is a number this page deliberately does not give: it depends on programme, site and scope, and borrowing a benchmark defeats the whole point of building yours up. The build-up from your own last jobs is the only version that prices your next one.