Things to know
A contingency line isn't hedging. It's the difference between an estimate that looks realistic and one that ignores the risk everyone in the room knows exists. Show 5-15% depending on project complexity as its own line. That signals to the customer that you've thought about what could go wrong, instead of promising a number you'll inevitably have to revise upward.
State your change-order policy in the estimate itself: "any changes to scope will be billed separately and require written approval before work proceeds." On a multi-phase project, scope drifts constantly as the customer sees progress and starts wanting adjustments. Agreeing this before work starts turns a potential argument into a simple, expected process.
Estimate or quote is a real decision, not merely a word choice. Use an estimate when hidden variables are genuinely likely: structural work, ground conditions, an older building with unknown wiring behind the walls. Use a quote for fixed-scope work like a single-room extension or a deck. A confident fixed price is easier to compare against competitors and reads as more assured.
Subcontractor allowances should be labelled as allowances, not fixed prices, when you haven't confirmed the sub-trade's rate yet. A line marked "electrical — allowance, subject to sub-contractor quote" is more honest than a firm number you're guessing at. It also protects you from being held to a figure that was really a placeholder when you first put the estimate together.
Typical builder / general contractor line items and UK prices
Indicative ranges, excluding VAT. Rates vary by region (London and the South East run higher) and by job size.
| Item | Unit | Typical range |
|---|---|---|
| Single-storey rear extension (shell + finish)Wide regional variation. | per m² | £2,000–£3,200 |
| Foundations (strip, including excavation) | per linear metre | £150–£300 |
| Steel beam install (RSJ) incl. padstones | per beam | £1,200–£2,500 |
| Building control fees | per project | £600–£1,500 |
| Skip hire (8 yard) | per skip | £250–£400 |
| Day rate, general builder | per day | £220–£350 |
| Structural engineer calculations (single beam) | per job | £300–£800 |
Common builder / general contractor jobs and how to price them
- Extensions
- Staged fixed price with provisional sums for unknowns (ground conditions, drainage) and prime-cost allowances for finishes.
- Knock-throughs
- Fixed price including the structural engineer’s steel spec, temporary support and building control.
- Loft conversions
- Staged price with fire safety and stair requirements stated.
- Refurbishments
- Room-by-room schedule of works with a daily rate for variations.
Regulations and certificates to reference
- Construction (Design and Management) Regulations 2015 — domestic clients’ duties pass to the contractor (or principal contractor where there is more than one). Projects over 30 working days with more than 20 workers at once, or over 500 person-days, must be notified to HSE.
- Building Regulations approval — extensions, structural alterations and loft conversions need building control approval (full plans or building notice). Say who applies and who pays the fees.
- Party Wall etc. Act 1996 — work on a shared wall or excavation near a neighbour’s foundations needs notice, usually two months for party wall work and one month for excavations. Party wall surveyor costs are normally the owner’s, not the builder’s.
- Planning permission / permitted development — state whether the design has planning permission, relies on permitted development, or needs a lawful development certificate.
Payment terms builder / general contractors commonly use
- Stage payments tied to milestones (foundations, wall plate, watertight, first fix, completion) rather than dates.
- A retention (commonly 2.5–5%) held by the client for a defects period on larger jobs.
- Variations: written instruction and price before the work proceeds.
Read more: Invoice payment terms explained · Payment methods to offer clients
VAT and CIS for builder / general contractors
VAT
Most work to existing homes is standard-rated at 20%. Building a new dwelling is zero-rated, and converting a non-residential building into a home or renovating a home empty for two years or more can qualify for 5%. Confirm eligibility before quoting the VAT line.
Construction Industry Scheme (CIS)
As a contractor engaging subcontractors, you must register for CIS, verify each subcontractor with HMRC, deduct at the rate given, and file monthly returns. Working for homeowners, you are not a CIS contractor for that job — but you are for the trades you hire.
General guidance, not tax advice — check your position with HMRC or an accountant.
Read more: Do I need to charge VAT on my invoices? · What must an invoice include? (UK legal requirements)
What this template includes
- Phase-based line items (demo, build, finishing)
- Subcontractor allowances
- Materials with mark-up
- Contingency line for unforeseen issues
- Detailed scope notes
Full guide
How to Start a Contracting Business as a Sole Trader
Frequently asked questions
A provisional sum is an allowance for work that cannot yet be defined, such as drainage diversion. A prime cost sum is an allowance for items the client will choose, such as a kitchen. Both are adjusted to actual cost, so list them separately from fixed prices.
Yes. On a domestic project, the client’s duties pass to the contractor, or to the principal contractor if there is more than one. You need a construction phase plan proportionate to the job.
The building owner, meaning your client, serves the notices and pays the surveyors. State on the estimate that party wall costs are excluded.
Yes. Tie them to physical milestones, such as watertight or first fix, rather than calendar dates. It protects your cash flow and gives the client a clear checkpoint.
Yes — 5-15% depending on project complexity. List it as its own line. This signals to the customer that you're planning realistically, and protects you when surprises happen.
Note in the estimate: "Any changes to scope will be billed separately and require written approval before work proceeds." This sets clear expectations from day one.
For projects with hidden variables (structural, ground conditions), use an estimate. For fixed-scope work like a deck or a single-room job, a quote is more confident and easier to compare.
More free templates
All templates- QuoteMason / BricklayerA clean quote template for masons and bricklayers. Itemise repointing, bricklaying day rates, and render repair — download a branded PDF in under a minute.
- QuoteKitchen FitterA professional quote template for kitchen fitters. Itemise units, worktops, and appliance connections — download a branded PDF in under a minute.
- QuoteBathroom FitterA professional quote template for bathroom fitters. Itemise tanking, sanitaryware, and trade coordination — download a branded PDF in under a minute.
Send your first estimate today
Free plan stays free forever. No credit card. Branded PDFs in 60 seconds.
Start free