Red flags in building quotes, from the builder's side

Most articles about dodgy quotes are written for homeowners. This one is written by the trade, for both sides, because good builders lose work to bad quotes every week, and the fastest way to stop that is for everyone to know what a bad quote looks like.

Why builders care about other people's bad quotes

When a cowboy quote lands on a kitchen table next to yours, it does two kinds of damage. First, its low number makes your honest number look inflated. Second, when that job goes wrong six months later, the client tells everyone that builders cannot be trusted, and the whole trade pays. A client who can read a quote properly is not a threat to a good builder. They are the best customer you will ever have.

So here are the flags, the reason each one matters, and what the professional version looks like instead.

Flag one: a single number with no breakdown

"Extension: £48,000" is not a quote, it is a wish. Without a breakdown by element or trade, nobody can tell whether the roof was priced, whether the electrics allowance is realistic, or whether the whole thing was reverse-engineered from what the builder guessed the client would pay. From the builder's side, a lump sum also removes your own best defence: when a client queries the total, you have nothing to point at.

The professional version is itemised by stage or element, so that a change to any part of the job has an obvious home. The full structure is laid out in what a professional builder's quote should include.

Flag two: no exclusions or assumptions

Counterintuitively, a quote that excludes nothing is more dangerous than one with a long exclusions list. Every building price rests on assumptions about ground, drains, structure and spec. A quote that does not state any has still made them, silently, and silent assumptions surface as mid-job "extras" with no paper trail. An honest exclusions list is a sign the builder has actually thought the job through.

Flag three: heavy deposit, vague stages

Deposits have a legitimate job: covering materials that must be ordered before work starts. On most domestic work that is somewhere around 5 to 10 percent, sometimes more when long-lead items like steels or bespoke windows are involved, and a builder should be able to say exactly what the deposit is buying. The flag is a large percentage up front combined with payment stages that do not map to visible milestones. Money should follow the work, not run ahead of it. A well-built schedule is described in stage payments that protect your cash flow.

Flag four: the invisible business

No trading address, no company number, no VAT position, no mention of insurance. Any one of these alone can be innocent, plenty of excellent sole traders are not VAT registered, but a quote should still say so plainly, because the difference between "no VAT, I am under the threshold" and a surprise 20 percent at invoice time is a four-figure argument. Public liability insurance stated on the quote costs nothing and answers the question every client is too polite to ask.

Flag five: the outlier price

A quote dramatically below the rest of the pack is pricing a different job, missing items, or planning to make the difference back in extras. Occasionally it is a hungry builder with an empty diary, which is honest, but then the breakdown will still stand up to scrutiny. The test is simple: ask the outlier to walk through their breakdown next to the others. A genuine sharp price survives that conversation comfortably. A fantasy price does not, and the way three honest builders can still land far apart is explained in why three builders quote three wildly different prices.

A word on what to actually do when a flag appears, because a flag is a question, not a verdict. Homeowners: ask about it directly and watch how the question lands. A professional answers comfortably, shows their working, and often thanks you for asking. Defensiveness, vagueness or a sudden discount are the real confirmation. Builders: when a client asks you these questions, treat it as buying behaviour. The client who interrogates your breakdown is taking you seriously, and they are the same client who will pay the invoice without drama, because they understood what they were buying from the start.

What a clean quote signals instead

Here is the encouraging part for builders: every flag above is cheap to fix, because they are all presentation and process rather than price. A tool like QS Quoter produces the professional version by default, a clean itemised client quotation with your exclusions and payment stages on it, plus a private tradesman copy holding your real costs, priced from a description or drawings at your own rates. The bar for looking professional has never been lower to clear, which is exactly why quotes that fail to clear it now stand out so sharply.