How programme length quietly changes your price

Two builders price the same extension with the same rates and the same quantities. One plans it in ten weeks, the other in fourteen. Their labour and materials match almost to the pound, yet the honest gap between their costs is thousands. The difference is time, and time is the cost driver most quotes never mention.

The meter that runs whether or not anyone is working

Some job costs are quantity-shaped: so many blocks, so many boards, so many labour hours to fix them. Others are time-shaped: they accrue per week that the site exists, regardless of how much got built that week. Scaffold hire beyond its included period, welfare and toilet hire, fencing rental, storage containers, your supervision visits, insurances allocated to the job, the van and fuel, parking permits. Individually modest, collectively they form a weekly burn rate that starts on set-up day and stops only at handover.

Suppose your time-shaped costs on a typical extension come to 450 GBP per week. Over a planned ten-week programme that is 4,500 GBP, and it belongs in the quote as deliberately as the bricks do. The same thinking underpins preliminaries explained: the site costs most builders under-price; programme is the multiplier that turns those small lines into large money.

A worked overrun, in cold numbers

Take that ten-week job. You price it at 82,000 GBP, expecting roughly 12,000 GBP of margin. It runs to thirteen weeks: a slow steel delivery, a wet fortnight, a client decision that arrived late. Nothing dramatic, nothing anyone would call a disaster. Now count what those three quiet weeks cost:

A quarter of the expected margin evaporated, and no single invoice ever said so. That is the defining feature of programme cost: it never presents itself as a bill, only as a thinner year. The opportunity cost line is the worst of them, because while the overrunning job absorbs your crew, the next deposit is not being banked, a squeeze that shows up in cash flow basics for a building firm.

Why long programmes hide inside "prelims"

The traditional place for time-related money is the preliminaries section, and that is also where it goes to die. A single "prelims" lump makes the time cost invisible, so when a client trims the quote, prelims are the line they attack, and when the programme stretches, nobody can see which part of the price just became inadequate. Better practice is to show the burn honestly: site set-up as fixed lines, then time-related items stated per week with the assumed programme visible. A quote that says "welfare and site facilities, 10 weeks at 45 per week" defends itself, and it gives you a ready-made, dignified basis for the conversation when the client's kitchen choice adds a month.

Speed is a margin strategy, not just a schedule

Flip the logic and it gets more interesting: every week you genuinely remove from a programme adds your weekly burn rate back to margin. Tight sequencing, materials ordered against a real programme rather than a hopeful one, decisions extracted from the client before they block the critical path, and a crew that is never waiting on information: these are estimating issues as much as site issues, because the quote is where the realistic programme gets set. Overpromising a fast programme to win the job, then running long, is the worst of both worlds: you priced fewer weeks than you will burn.

Be honest about seasonality too. A January start on external works carries more weather risk than a May start. If the client's timeline pushes the wet trades into the wet months, the programme, and therefore the price, should say so.

When the delay is theirs, the arithmetic is ready

Not every slipped week is yours to fund. Clients stall on tile choices, change the kitchen layout after first fix, or take three weeks to sign off the glazing order. If your quote already states the assumed programme and shows the weekly time-related costs, then a client-caused delay has a pre-agreed price: the weeks, times the visible weekly rate, plus any specific consequences like extended scaffold hire. That conversation, held early and calmly with the numbers already on the table, is a routine administrative matter. The same conversation held at the end of the job, with no stated programme and no visible weekly rate, is an argument you will probably lose or decline to have. Write the assumption, show the rate, and delays become billable events instead of silent donations.

Put programme into the quote machinery

None of this requires a planner's Gantt chart. It requires the quote to know how long the job takes and to price the weeks explicitly. When QS Quoter generates a quote from your description or drawings, the output is a fully itemised document at your rates where time-driven lines are visible and editable, so stretching the assumed programme is a line edit rather than a guess. Your private copy shows the cost basis week by line; the client copy shows a professional, defensible structure. Pair that with a firm quote validity period, as discussed in exclusions and assumptions: the small print that saves jobs, and time stops being the silent partner who takes a cut of every job.