A headline figure is easy to produce. Pricing the whole job, so that figure still holds up once you're on site, is the harder part. And when you look at what builders miss when pricing a job, it's almost never the foundations or the roof. It's the lines that don't look like much on the drawing and add up to real money by the end.
Nobody leaves things out on purpose. They get left out because the price was put together fast, from the big items down, and the small ones never made it onto the page.
What builders miss when pricing a job, line by line
The same items turn up again and again when a job is priced in a hurry. None of these is exotic. That's the problem: they're so ordinary they're easy to forget.
- Preliminaries. Site set-up, welfare, skips, scaffold hire, temporary fencing, protection, supervision time. Real costs that don't appear on a single drawing.
- Small quantities. Lintels, cavity closers, DPCs, cavity trays, wall ties, fixings, sealants. Each one small. Together, often not.
- Work between trades. Making good after the electrician and plumber, builder's work in connection with services, fire stopping, boxing in. Everyone assumes someone else has it.
- Waste and cutting. Measured quantities are net. Materials arrive in fixed sizes, and some of every delivery ends up in the skip.
- Drawing notes and spec clauses. The note in the corner of a section that says "all new drainage to be CCTV surveyed" is a cost, even if it's in small print.
- Access and logistics. Narrow side access, no parking, material handling by hand. A tight site slows every trade.
Look at the work between trades in particular. It's the one most likely to fall through the gap, because each subcontractor prices their own package and nobody prices the bit where two packages meet.
Why the small lines hurt more than the big ones
A big item gets checked. You'd notice if the roof was missing from your price. A small item doesn't. Leave off the cavity closers or the making good and the total still looks reasonable, so nothing flags it.
Then the job starts. The closers get ordered, the plasterer spends two days making good, the skip needs changing twice more than you allowed. Each one is paid for out of margin, because there was nothing in the price to cover it.
On a job priced keenly to win, a handful of missed small lines can be the difference between a decent profit and working for nothing. That's why measuring the whole thing matters more than measuring the big bits very carefully.
The lines that sink a price are rarely the big ones. They're the small ones nobody thought were worth measuring.
Every element gets counted, not just the obvious ones
This is what a proper estimating service for builders is built to do. Measuring the whole job to NRM2 means the preliminaries, the small quantities and the in-between work are in the number from the start, because the method works through every element in order rather than jumping to the obvious ones.
A proper takeoff also reads the notes and the specification alongside the drawings. That's where a lot of cost hides: in a single line of text rather than a shape on a plan. Measuring by eye misses it every time. There's more on this in what a proper takeoff catches that a quick measure misses.
Anything that can't be measured because the information isn't there gets flagged as an assumption, so you can see it and decide how to deal with it.
The breakdown is there when you need to defend it
A client asking to see the numbers behind your price is easier to answer with an itemised bill than with a total and a shrug. The breakdown shows where every pound sits.
It also works in your favour when things change. If the client adds a window or moves a wall, you can point to what was in the original price and what wasn't. Without a breakdown, every change becomes a negotiation from scratch.
And because the estimate is priced on current UK rates you recognise, not a generic figure that bears no relation to what you'd pay your labour and suppliers, you can adjust any line where your own rates differ. The structure stays. The numbers become yours.
Building the small lines into your own routine
If you price some jobs yourself, you can close most of these gaps with a habit rather than more hours. Keep a short list of the items above and run through it at the end of every price, before you add the margin. It takes minutes, and it catches the lines a tired brain skips.
Price the preliminaries as their own section, not as a percentage on top. Work out how many weeks the job will run, then what the skips, scaffold, welfare and supervision actually cost over that period. A percentage copied from the last job assumes this job looks the same. It rarely does.
And when a subcontractor's quote comes in, read what it excludes, not just the total. The exclusions list is often a map of exactly the work that falls between trades. Whatever they've left out is now yours to price.
A quick check before your next price goes out
Go through the list above and, for each item, find where it sits in your price. Not "it's in there somewhere". Find the actual line. If you can't find three or more of them, those are what builders miss when pricing a job, and they're probably missing from yours too. Put them in before the tender goes out, not after the first valuation.