You can do brilliant work on site and still go backwards on paper. When a job loses money, the cause is rarely the build itself. It is usually a quote that was wrong before the first brick was laid.
This post walks through the most common reasons builders lose money on quotes, then sets out the habits that protect your margin. None of it is complicated. It is mostly about pricing the same way every single time.
The quote is where most profit is won or lost
By the time you are on site, your margin is largely fixed. The price is agreed, the scope is set and the programme is running. If the numbers were soft, no amount of effort on the tools will claw it back.
That is why the quoting stage deserves as much care as the build. A tender is not just a number you send to win work. It is the budget you have to deliver against, so the quality of your estimate decides whether the job pays.
The usual reasons the money disappears
Lost margin tends to come from a short list of repeat offenders. Most builders recognise at least three of these from jobs they would rather forget.
Missed scope and gaps in the take-off
If an item is not measured, it is not priced, and if it is not priced you pay for it out of margin. A rushed take-off misses awkward details: extra lintels, builder's work in connection with services, making good, waste and offcuts.
A disciplined take-off measured off the drawings is the single best defence. It forces you to account for every element rather than carrying a number in your head.
Forgotten preliminaries
Preliminaries are the cost of running the job rather than the physical work: site setup, welfare, scaffolding, skips, plant hire, supervision and insurances. They are easy to underprice because they do not appear on the drawings.
On a typical project prelims can run from around 8 to 15 per cent of the build value, sometimes more on tight or constrained sites. Leave them out and you have given that money away.
Optimistic labour and productivity
Labour is where estimates drift furthest from reality. It is tempting to price the day you hoped for rather than the day you usually get, with no allowance for weather, access, deliveries or rework.
Base your gang rates and outputs on what your teams actually achieve, not the best shift you ever had. Honest productivity numbers are worth more than a low headline price you cannot deliver to.
Margins too thin to absorb risk
A quote with almost no overheads and profit has no shock absorber. One price rise or one bad week and you are working for nothing.
Set a clear overheads and profit figure on every job and treat it as non-negotiable. It covers your office costs and the risk you carry as the contractor.
How to stop the leak
Plugging the gaps is mostly about method. The builders who hold their margin are not luckier, they just price consistently and check their numbers before they go out.
- Measure a full take-off from the drawings for every job, not just the big ones.
- Price preliminaries as a named line, with scaffolding, welfare, plant and supervision listed out.
- Use labour outputs from your own recent jobs, then add a sensible allowance for the things that always go wrong.
- Carry a contingency for genuine unknowns and a separate provisional sum where the scope is not yet fixed.
- Add overheads and profit as a visible figure, and refuse to discount it away to win work.
Build a method you can repeat
The goal is a pricing process that looks the same on every tender, so you can compare jobs, learn from them and spot mistakes before they cost you. Pricing against a structure such as the RICS New Rules of Measurement keeps your estimates ordered and comparable from one project to the next.
If you do not have time to price properly between site visits, that is often where the slips happen. A professional estimating service gives you a measured, fully priced tender without pulling you off the tools, so the quote that wins the work is also the budget that protects your profit.