Pricing the Preliminaries: Building the Weekly Rate Off the Programme

The people on site who never install anything

Supervision is usually the largest single line on the page and the one most often priced as a job title rather than as a cost. A site manager, an assistant, a setting-out engineer, a planner attending fortnightly, a surveyor one day a week, a safety adviser monthly, a document controller shared with two other jobs. Each is a fraction of a person over a stated window, paid for at what employing that person actually costs — salary plus the employer's on-costs, the vehicle, the phone, the accommodation on a job nobody can commute to. That is the burden arithmetic the site's contractor-pricing guide works through in full, applied here to somebody who produces no measured output at all, so no rate anywhere in the bill can absorb it.

Some of these roles are not a management preference. The Construction (Design and Management) Regulations 2015 place duties on the principal contractor to plan, manage and monitor the construction phase and to secure cooperation between contractors, which is a job somebody holds rather than a document somebody files. OSHA 29 CFR 1926 Subpart C puts accident prevention responsibility on a competent person authorised to take corrective measures, and individual operations name competent persons of their own — Subpart P for excavations, Subpart L for scaffolds. BS 5975 sets out the procedural control of temporary works and the appointment of a temporary works coordinator, which on a job with much falsework, propping or facade retention is a genuine part-time role and not a box on a chart. NFPA 241 requires a fire prevention programme with somebody responsible for it. When the number gets challenged these are the easiest lines to defend, because they were never yours to remove.

The trap in the other direction is the shared resource, a favourite of a tight bid: a surveyor covering three jobs, a manager splitting his week between two. Sharing is legitimate and common, and it becomes a fiction the moment the histogram assumes more of it than the jobs will permit — two sites do not obligingly peak in different months, and when they collide the cover is bought in at short notice at a price nobody tendered. Write the fraction on the build-up, and write what happens if the other job wants the same weeks.

One line hides behind all of them and is invariably missed: the attendance the trades need from you rather than from each other. Somebody unloads the delivery that arrives when the subcontractor is not there, holds the keys, runs the induction, chases the method statement, books the lift, moves the cabin and stands with the meter reader. On a small job that is the manager doing it between other things and it is already inside his week. On a large one it is a general foreman and two labourers — a resource priced by the week, appearing in no measured item anywhere.

Scaffold and plant run on a clock that somebody else is holding

Site-wide plant is where the fixed and time-related split earns its keep, because almost every item on this part of the page is both at once. A scaffold is an erection price, a weekly hire, adaptations as the job changes, and a dismantle. A tower crane is a foundation, an erection with a mobile crane and a road closure, statutory examination, then a weekly hire with an operator and a slinger attached, then a dismantle with the same road closure again. A hoist is the same shape. Price any of them as a single lump and the first thing the programme does is make the number wrong, because slip moves the hire weeks and leaves the erection cost exactly where it was.

The hire period is the part not in your gift, and it is the specific way scaffold overruns. You erect it for the bricklayer and it comes down when the last person who needs to stand on it has finished — the roofer, the window fitter, the renderer, the painter, whoever does the flashings nobody sequenced. The hire period is set by the tail of somebody else's programme rather than by the trade that asked for it, so an estimator pricing it against the masonry duration has priced perhaps half of it. Design and adaptation carry their own money: NASC TG20 covers good practice for tube and fitting scaffolding and the compliance sheet route for common configurations, BS EN 12811-1 sets performance requirements, OSHA 29 CFR 1926 Subpart L governs the North American equivalent, and anything outside the standard configurations is a designed scaffold with an engineer's drawing behind it — a fee and a lead time.

The rent-or-own question turns up in the middle of this. The bare break-even is trivial — purchase price divided by daily hire rate gives the number of hire days at which buying is level — and it ignores everything ownership drags along: maintenance, statutory examination, transport between sites, storage, an operator you employ rather than hire, the money tied up, the residual at the end. Hire is quoted off a rate card whose weekly and monthly rates sit well below seven or thirty times the daily, so the honest comparison uses the structure you would be quoted rather than a daily rate multiplied out. Do the break-even anyway: it frames the decision in the only unit that matters here, days on this site. Then remember that whichever way it goes the cost lands in the preliminaries as weeks. A machine you own is not free while it stands there, only a cost you have stopped being invoiced for, and the surest way to lose money on owned plant is to let a job carry it for months with nothing to do.

Reading the exclusions until the gaps show

Every subcontract quotation on the comparison sheet has a list at the bottom of things it does not include, and that list is where preliminaries are silently created and silently duplicated. Removal of rubbish from the work area to a container provided by others. Task lighting by others. Unloading and distribution by others. Scaffold by others. Power and water free of charge at each floor. Attendance for testing. Protection of the finished work. Every one of those clauses is a cost that has to be somewhere, and there are exactly two ways to get it wrong.

The gap is the expensive one: nobody prices it, because each party assumes the other did, and it surfaces on site as an argument you lose while the work stands still. The double count is quieter and loses you the job rather than the money — the prelims carry a general clean, every trade has also priced clearing their own, and you have bought the same broom twice for a reason nobody will ever tell you. Both are found the same way, by reading the exclusions across every package at once and marking who does each thing. It is an afternoon, and the highest-yield afternoon in the tender.

Waste is worth doing carefully, being the clearest case of a cost that is neither purely time-related nor purely quantity-related. The volume is driven by the trades — packaging, offcuts, plasterboard, strip-out arisings — and the number of exchanges by how long those trades are there and how much they were allowed to leave for you. A container also carries two charges that behave differently: a delivery and collection charge per exchange, and a rental accruing while it stands. A skip sitting half-full for three weeks because nobody booked the exchange is paying rental on air, which makes this one of the few preliminaries lines that responds to management rather than to money. Segregation and compound layout belong to the waste-compound page; the tender question is narrower — how many exchanges over how many weeks, and which of them the trades should have been paying for.

1. Pull the exclusions off every package quotation into one column, in the subcontractor's own words, and do not summarise them.
2. Against each, write who does it: the trade, your preliminaries, or another package. Anything without a name in that column is a gap, and it costs more later than it costs now.
3. Circle anything named twice. That is money in your bid no competitor is carrying, and it is nearly always cleaning, unloading, task lighting or scaffold adaptation.
4. Convert the ones landing on your preliminaries into resources with windows: labourers by the week, a forklift by the month, a container with a stated exchange frequency.
5. Feed that frequency back into the histogram, because it is not constant — strip-out and first fix produce nothing like the volume of second fix, and one average hides both ends.

The weekly rate is the number you will be paid at

There is a reason to do all of this that has nothing to do with winning the tender. Sooner or later something happens that is the client's risk and not yours — late information, an instruction that stops a work face, access promised and not given — and you apply for an extension of time. Time is not money, though, and the two travel under separate clauses: an extension protects you from damages, while the cost of having been there longer comes from somewhere else. In JCT that is the loss and expense provisions and the Relevant Matters triggering them; in NEC4 a compensation event assessed on Defined Cost plus Fee; under AIA A201 the extension of time in Section 8.3 sits apart from the claim for what the delay cost, and FIDIC's Red Book separates the two for the same reason.

What every one of those routes eventually asks for is the same thing: what did it actually cost you to keep this site standing for the extra period. That is the preliminaries build-up, week by week, with dates against each resource. A contractor who priced a percentage has nothing to hand over. A contractor with a resourced histogram has a contemporaneous document showing exactly which staff and which plant were committed in which weeks — which is not proof of what was spent, but it is the baseline everything else gets measured against, and it was written before anybody had a reason to be self-serving about it.

Two refinements are worth having straight before the argument rather than during it. The first is which weeks get valued: the Society of Construction Law's Delay and Disruption Protocol is clear that compensation for prolongation is assessed by reference to the period in which the effect of the employer risk event was felt, not the extended period tacked on at the end — different weeks, with different resources standing on the site, which is why the histogram matters more than the average. The second is that prolongation and disruption are not the same claim: prolongation is the site being open longer, disruption is the same work costing more per unit because of how it had to be done, and no multiple of weeks recovers it. Head office overhead during a delay is a third question, argued through named formulae — Eichleay in United States federal contracting, Hudson and Emden in the British literature the Protocol discusses — and it is contested ground rather than arithmetic.

For tender day the consequence is short. The weekly rate you build now is the rate you will be quoting back at somebody in eighteen months, so build it as though it will be read by a quantity surveyor who is not on your side. Keep the workings, date them, note the assumptions about working hours and shared staff, and keep the one-off costs separate from the weekly ones exactly as you did here — because standing a site down and starting it up again costs the same whether the stoppage was two weeks or six.

Risk on this page is counted in weeks before it is counted in money

Contingency on a tender usually arrives as a percentage on the total, which has the same defect as a percentage for the preliminaries themselves: it is not connected to anything. On the preliminaries page there is a better exchange rate available, and you have just built it. Every risk that threatens the programme converts into money at exactly one number — the weekly rate — so the honest question is not what percentage to add but how many weeks of exposure this particular job carries.

That makes the risk register something you can price rather than something you file. Weather is the clearest case, and whether it is your risk or the client's is a contract question with a real answer: JCT lists exceptionally adverse weather conditions among the Relevant Events, which buys time and not money, while NEC4 provides a weather compensation event measured against data recorded at a stated weather measurement place over a stated return period. Where neither applies, a winter start on a job with twelve weeks of groundworks is carrying weeks that belong to you. The same treatment works for a ground risk in the soil report, a condition with a discharge period, a diversion in a utility's hands, or a package with one credible supplier. AACE International Recommended Practice 40R-08 is the reference for doing it as contingency estimating rather than as padding, and it keeps contingency separate from management reserve, which was never the estimator's to hold.

Two disciplines make the result honest. Size the buffer against the time-related total rather than against the whole preliminaries figure, because a delay does not re-erect a scaffold or re-cast a crane base; the fixed lines are already spent. And write the weeks down alongside the money, because weeks survive an adjudication meeting in a way that a percentage never does — nobody argues a contractor out of a percentage they cannot see, but a room full of people can look at three weeks of assessed weather exposure and decide, on the record, to carry two.