How building quotes actually work
It is tempting to want a number over the phone before committing time to a site visit, but for genuine building work that number is rarely worth much. Here is why, and what a proper quote actually looks like.
Why a phone estimate is close to worthless
A single-storey extension quoted at £2,400 to £3,200 per square metre is a real, published range, and it is also nearly useless for your specific project: ground conditions, roof junction complexity, existing drainage position and site access can all move a project from the bottom to the top of that range or beyond it. A number given without seeing the site is a guess, not a quote.
What a site visit actually establishes
Access for materials and machinery, existing structural condition, drainage and services positions, and anything specific to the property (a party wall, an awkward roof junction, an older foundation of unknown depth) that changes cost and approach. None of this is visible from a phone call or even good photos.
What a proper written quote includes
A specification of the work, what materials are included, what is excluded (decorating, landscaping reinstatement, and similar finishing items are common exclusions worth confirming), a payment schedule tied to project stages, and a realistic timeline. If a quote is a single number with no detail behind it, ask for the breakdown before agreeing to anything.
Why the first number sometimes changes
On an older property especially, it is normal and honest for a scope to be revised once a wall or floor is opened and something unexpected is found, damp, an old drain run, timber in worse condition than visible from outside. What separates a good process from a bad one is being told and asked before that extra cost happens, not finding it on the final invoice.
What we do differently
Every project starts with a free, no-obligation site visit specifically so the quote that follows is a real number, not a guess. If something changes once work starts, you hear about it and agree it first.
Free site visit and quote
Tell us about the project at hello@sandwichbuilders.co.uk or on WhatsApp. We'll arrange a site visit to give you a proper quote.