A real single-storey rear extension quote, priced line by line from the architect's drawings — 105 items totalling £141,727.41 excluding VAT, in Surrey. Both the client-facing quote and the full bill of quantities behind it are below. Free, no email.
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A full-width single-storey rear extension with a flat roof and lantern, a side extension housing a utility room and cloakroom WC, and a new entrance porch — priced to a plastered shell with electrics and plumbing throughout.
Each line states how much, in what unit, at what rate. The foundations section is £40,491 because of the measured volumes and the stated depth assumption, not because it felt like a quarter of the job. Where the drawings do not show something — the foundation depth — the quote says so rather than quietly picking a number. That is what makes it checkable.
The client-facing PDF describes the work in sentences a homeowner can follow, while the Excel bill keeps the measured detail underneath. Same numbers, two audiences.
What was assumed rather than confirmed is stated, with the affected scope named. That is what lets a quote go out before every question is answered without hiding risk.
Two anonymised proposed plan and elevation sheets for a genuine Surrey job — a figured ground-floor plan and the matching elevations. That is everything the pricing had to work from: no site visit, no schedules, no engineer's package.
Corrected in version 0.3. Cavity wall areas, wall ties, fascias, guttering, downpipes and the two pitched tiled roofs were recomputed or added from the drawings, with a formula recorded against every change.
Caught by an automated completeness check during the version 0.3 rebuild: the flat roof's decking, insulation and membrane were priced, but the structural joists that carry them were sitting at nil. They are now priced from the measured deck area with the formula recorded in the same correction ledger.
Still provisional. The planning sheets contain no foundation section or depth evidence, so foundations are priced as 1.5 m trench-fill to the full 31.6 m perimeter, matching the original builder allowance — and the quote says so. Shallower confirmed ground would reduce that section.
The measured result and the human correction are kept separate: the version 0.3 ledger records every changed quantity with its drawing formula, and nothing else about the priced result was touched. A quote that reconciles can still contain a wrong quantity — so this page states what was checked and what remains assumed rather than claiming the whole quote is beyond question.
Yes. It is a genuine single-storey rear extension in Surrey, measured line by line from the architect's drawings, with the client's details removed. The quantities, rates and £141,727.41 tender sum are exactly as the priced result produced them — the one human correction pass is documented on this page, and nothing has been rounded or tidied for presentation.
There is no single answer — it depends on floor area, ground conditions, specification and region, and this example is one job in Surrey rather than a benchmark. What it does show is the shape a defensible extension quote takes: eleven sections, 105 measured lines, and a rate against every one.
On this job foundations, ground-floor slab and drainage came to £40,491 of the £141,727 — well over a quarter. The depth is stated as a provisional assumption: the planning drawings carry no foundation section, so the quote prices 1.5 m trench-fill matching the original builder allowance and says so. That is exactly the sort of figure a client queries, which is why it is broken into measured lines rather than presented as one number.
The structure, yes — and the free blank template on this site gives you the same eleven sections ready to fill in. The rates should be your own: they reflect one contractor's costs in one region at one point in time.
Want a blank one to fill in instead? Get the free quote template → Pricing a loft instead? See the bill of quantities example →
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