Most disputes over money on a building project trace back to something that was never clearly agreed at quotation stage — an exclusion nobody read, a provisional sum that turned out much higher, or a specification that both sides interpreted differently.
A short list of checks before signing catches most of these problems while they're still free to fix, rather than after the trench is dug or the kitchen is ordered.
Read the exclusions before the total
Every quote has a list of what is excluded, usually near the bottom, and it is the single most important section on the page. Common exclusions include curtains and blinds, external landscaping, drainage connections beyond the boundary, and decorating beyond making good.
An exclusions list that reads as generic boilerplate rather than specific to your job is worth querying — ask directly whether items you assume are included, such as making good to adjacent rooms, actually are.
Check the specification actually matches
A quote is only comparable to another quote if both are priced against the same specification — same materials, same finishes, same fixtures. 'Standard sanitaryware' or 'quality kitchen units' are not specifications, they are placeholders, and two builders can read them completely differently.
Where the specification is vague, ask for named products or, at minimum, a stated budget allowance per item, so you know what you're actually comparing when the totals land.
Identify every provisional sum
Provisional sums are legitimate where genuine uncertainty exists, but each one is a figure that can move once the real cost is known. Before accepting a quote, list every provisional sum and ask what would trigger it changing, and by roughly how much.
A quote weighted heavily towards provisional sums on items that could reasonably have been measured or specified in advance is worth pushing back on — it may be shifting risk onto you that the builder could have priced properly.
Check the validity period and what can still change
Material and labour prices move, so most quotes carry a validity period, often thirty to ninety days, after which the builder can revise the figure. If you don't intend to start immediately, check how long the price actually holds and what happens if it lapses.
Also check whether the quote assumes a particular start date or continuous working — a quote based on an unbroken run of weeks will cost more to honour if the programme gets interrupted or paused partway through.
Compare like with like, not just the bottom line
Once specification, exclusions and provisional sums are aligned across competing quotes, the comparison becomes genuinely useful rather than comparing three unrelated numbers. It's common for the middle-priced quote to be the most complete once this exercise is done, with the cheapest missing scope and the most expensive over-specified.
Asking each builder the same clarifying questions, in writing, and keeping their written answers alongside the quote itself gives you something to refer back to if a dispute arises later.
Common questions
What's the biggest red flag in a quote?+
A specification so vague that it can't be pinned down to actual products, finishes or quantities. Vague specifications are where scope disputes and unexpected extras almost always originate.
Should I ask a builder to itemise a lump-sum quote?+
Yes — a reasonable builder should be able to break a lump sum into trade or element totals on request. If they can't or won't, it suggests the figure wasn't built up from measured quantities in the first place.
How long should a quote remain valid?+
This varies, but thirty to ninety days is typical for material-sensitive work. Ask specifically rather than assuming, particularly if you need time to arrange finance or finalise a mortgage before committing.
Ask us to walk through our quote with you line by line
We're happy to explain every figure, including exclusions and provisional sums, before you decide.