Extension quote template for UK residential builders.
A better extension quote starts with sections, not a lump sum.
Use a free UK extension quote template covering groundworks, shell, roof, first fix, second fix, preliminaries, margin, variations, and stage payments.
What this page helps you decide.
A useful extension quote template breaks the job into preliminaries, groundworks, structure, shell, roof, windows, first fix, second fix, finishes, external works, overhead, margin, VAT, stage payments, exclusions, and variations. It should make allowances and assumptions visible rather than hiding the whole project inside one lump sum.
Source note: Built from QuoteBuild quoting workflows for UK residential extensions. Confirm drawings, specifications, structural information, measurements, supplier prices, VAT treatment, access, ground conditions, and contract terms for the actual job.
Extension quote preview
Break the price into build stages so clients and cash flow stay clear.
Template preview
Groundworks
£11,800
Excavation, foundations, drainage
1
Shell
£24,500
Brickwork, steels, roof structure
1
Services
£7,900
First fix plumbing and electrical
1
Finish
£13,600
Plastering, second fix, decoration
1
| Section | Item | Qty | Allowance |
|---|---|---|---|
| Groundworks | Excavation, foundations, drainage | 1 | £11,800 |
| Shell | Brickwork, steels, roof structure | 1 | £24,500 |
| Services | First fix plumbing and electrical | 1 | £7,900 |
| Finish | Plastering, second fix, decoration | 1 | £13,600 |
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Copy wording
Scope wording
This quote is based on the scope and assumptions listed. Any work outside this scope will be priced and agreed before proceeding.
Payment wording
Payment stages are due at the milestones shown. Materials, variations, and additional work may require separate agreement.
Start with preliminaries and scope
Record drawings, site setup, welfare, access, scaffolding, skips, protection, insurance assumptions, and who is responsible for approvals before pricing the build stages.
Separate groundworks and structure
Excavation, muck-away, drainage, concrete, masonry, steels, temporary works, and unknown ground conditions need visible allowances and assumptions.
Price the shell and roof
Break out walls, insulation, roof structure, coverings, rooflights, windows, doors, leadwork, rainwater goods, and interfaces with the existing house.
Allow for every trade
First fix, second fix, plumbing, electrics, heating, plastering, carpentry, decoration, flooring, kitchens, and bathrooms should not disappear inside a general labour figure.
Protect cash flow
Set payment stages against real delivery milestones so early materials, scaffolding, and subcontractor costs do not leave the builder funding the project.
Make changes chargeable
State exclusions, provisional sums, client-supplied items, quote validity, and the variation approval process before work starts.
What to do before you send the price.
Step 1
Write the scope, drawings, specification, assumptions, and exclusions.
Step 2
Break the project into preliminaries, groundworks, structure, shell, roof, services, finishes, and external works.
Step 3
Add labour, materials, plant, waste, access, subcontractors, overhead, contingency, and profit.
Step 4
Set VAT treatment, quote validity, stage payments, and variation terms.
Step 5
Review the final client quote against the drawings and latest supplier prices before sending.
Free download
Send me the builder quote template.
You will get the spreadsheet template and calculator. If you want the quote-to-profit workflow, start the trial after.
Keep pricing the job properly.
Extension cost calculator
Sense-check an early extension budget before building the detailed quote.
Read guide
Builder quote template
Use the wider builder template for extensions, lofts, and refurbs.
Read guide
Extension cost per m² guide
Understand why an early square-metre check is not a final quote.
Read guide
How to price building work
Work from scope and direct costs through to overhead and margin.
Read guide
Quick answers.
Should an extension quote be itemised?
It should be structured enough to explain the price and protect the builder, even if every supplier line is not shown to the client.
Can QuoteBuild record staged payments?
Yes. Accepted quote totals can be turned into manual stage records so you can track what has been paid directly to you.
Is the extension quote template free?
Yes. You can use the on-page extension quote structure and request the free spreadsheet template before deciding whether to build the live quote in QuoteBuild.
What should be excluded from an extension quote?
Common exclusions or assumptions include planning and professional fees, utility upgrades, unknown ground conditions, asbestos, client-supplied items, specialist surveys, and work outside the stated drawings and specification.
How should stage payments be set?
Tie stages to clear delivery milestones and expected cash outflow. The exact structure depends on the job and contract, but it should be agreed before work begins.