Builder Pricing Guide UK — Day Rates, Extension Costs and How to Quote Building Work (2026)

Building work is unlike most trades when it comes to pricing. Jobs span weeks or months, involve multiple sub-trades, carry significant material cost and can change dramatically once ground conditions or structural surprises emerge. Get your pricing wrong and you're not just losing a few hours — you're losing thousands.

This guide covers UK builder day rates for 2026, typical fixed-price costs for common building projects, how to build a quote that protects you, and where most builders leave money on the table.

UK Builder Day Rates in 2026

Day rates are less common in the building trade than in other trades, but they're worth knowing — both as a benchmark for costing labour into fixed-price quotes and for the minority of jobs where time-and-materials billing makes sense.

Typical UK day rates in 2026 (labour only, excluding materials and VAT):

• Labourer / groundworker (general): £130–£200/day
• Skilled tradesperson (bricklayer, carpenter, plasterer): £200–£350/day
• Site manager / project manager: £350–£500/day

London and South East premium: add 25–40% on top of the figures above. A skilled tradesperson charging £250/day in the Midlands would typically charge £310–£350/day for equivalent work in London.

Solo builders quoting their own labour should think of their day rate as a floor, not a ceiling — your rate needs to absorb business running costs, insurance, vehicle, tools, marketing, admin time and pension contributions that an employed site operative does not bear.

Fixed Price vs Day Rate: Which Applies to Building Work?

Almost all substantive building work is quoted as a fixed price (or fixed price with provisional sums). Clients commissioning extensions, conversions or structural work want certainty on cost before they commit planning permission fees, architect fees and often remortgaging decisions. A day-rate-only quote signals you haven't fully scoped the job.

Day rate or time-and-materials billing does apply in a few situations:

• Small repair and maintenance jobs where the scope genuinely cannot be assessed until the work starts
• Refurbishment projects where a client is changing their mind about spec as the job progresses (make sure this is documented — it has a habit of leading to disputes)
• Investigative work: opening up walls, digging trial pits to assess ground conditions
• Emergency reactive work where there is no time to survey and quote

For everything else, price it as a fixed job. Clients who push back on fixed prices in favour of day rate are often hoping to pay for fewer days than the job actually takes.

Common Building Job Prices (Supply and Fit, 2026 UK)

These are market-rate ranges for the full job including labour, materials and plant. They exclude VAT, architect fees, structural engineer fees, planning fees and building control fees unless stated. Prices assume a standard residential project in England or Wales outside London — add 25–40% for London and commuter belt.

• Single-storey rear extension (basic build shell): £25,000–£45,000
• Double-storey extension: £45,000–£90,000
• Dormer loft conversion: £35,000–£65,000
• Garage conversion (to habitable room): £8,000–£20,000
• Internal wall removal — load-bearing (inc. RSJ supply and fit): £2,000–£5,000
• Internal wall removal — non-load-bearing: £800–£2,000
• New damp proof course: £2,000–£5,000
• Underpinning (per linear metre): £800–£1,500
• New build detached house (turnkey build cost, exc. land, architect, planning): £1,500–£2,500/m²

These figures assume a standard specification. High-spec finishes, unusual structural requirements or awkward access can push costs well above the top of these ranges.

The Per-m² Approach

For larger projects — extensions, conversions and new build — it's common to quote (and benchmark) on a cost per square metre of build area. For a typical extension in 2026, expect £1,500–£2,500/m² supply and fit for the complete shell. That figure should cover groundworks, foundations, external walls, roof structure and covering, external windows and doors, first fix (electrical, plumbing, joinery) and second fix, plastering and basic floor finish.

The per-m² figure is useful for a quick sense-check on your quote before you submit it. If you're quoting an 18m² extension and your total is £18,000, something is wrong — either you're underpricing significantly or you've missed major scope items.

Key drivers of where a project lands within the range:

• Specification: standard block-and-render vs high-end timber frame with triple glazing and underfloor heating
• Structural complexity: flat roof vs pitched, standard openings vs large steel spans
• Ground conditions: solid chalk vs made ground requiring deeper foundations or engineered solutions
• Access: side access for skips and deliveries vs rear-only through a narrow alley
• Local labour market: rural vs urban, North vs South
• Materials specification: standard block, standard timber vs structural insulated panels, engineered timber

How to Quote a Building Project Correctly

1. Survey Before You Quote

Never quote from a phone call, a photo or a set of planning drawings alone. Visit the site. Look at access, existing structure, services locations, ground type if possible, and anything that could affect the programme or cost. A 30-minute site visit can save you a five-figure loss later.

2. Scope It Precisely

Your quote must be explicit about what's included and what's not. A typical extension quote should state clearly:

Included: groundworks and slab, external walls, roof structure and covering, external windows and doors, first fix carpentry, first fix electrical and plumbing (by named sub-trades), second fix carpentry, plastering, screed, basic floor finish.

Not included: kitchen units and appliances, bathroom sanitaryware and tiling, internal decoration, landscaping, architect fees, structural engineer fees, building control fees, planning fees.

Being explicit about exclusions is not about being difficult — it's about making sure the client understands what they're buying so they can budget the full project. Builders who leave this vague are the ones who end up being asked to do the kitchen "because it was included in the quote."

3. Use Provisional Sums Where Genuine Uncertainty Exists

Some items genuinely cannot be priced until the work starts — groundworks are the classic example. You do not know how deep you need to go until you excavate. The right approach is to include a provisional sum (PS) in your quote: "PS for groundworks and foundations: £8,000. This is an estimate based on standard ground conditions. Final cost will be adjusted based on actual depth and ground conditions found on site, agreed with the client before works proceed."

Explain this clearly to the client before they sign. A client who understands provisional sums is far less likely to dispute them later than a client who thought the price was fixed and then gets a bill adjustment.

4. Handle Client-Supplied Materials Carefully

Some clients want to supply their own materials to reduce cost. If you allow this, reduce your price accordingly — and reduce your liability. Your quote should state: "Labour only for [item] — materials supplied by client. Trade2Base accepts no responsibility for the quality, suitability or warranty of client-supplied materials." The moment something goes wrong with a client-supplied material and it affects your work, you're in a difficult position. If you're not comfortable with reduced control, it's reasonable to decline.

Getting Payment Terms Right

Staged payments are non-negotiable on any building project over a few thousand pounds. You should never be significantly out of pocket on materials and labour while waiting for a client to pay. A typical staged payment structure for an extension:

• Mobilisation deposit (10–15%): paid before any work starts, covers initial ordering and plant mobilisation
• Groundworks complete (20–25%): slab poured and inspected
• Watertight (25–30%): walls up, roof on, windows and external doors installed
• Practical completion (25–30%): all works complete, snagging list issued
• Retention release (5–10%): typically 3–6 months after practical completion, once snagging is resolved

The retention is common on larger projects and gives the client comfort that you'll return to address defects. Make sure the retention release date and conditions are clearly written into your contract — vague retention clauses lead to retention funds that are never released.

Managing Variations (Change Orders)

Clients change their minds. On a building project, those changes cost money. Every variation — whether it's moving a window, upgrading roof tiles or adding a downstairs WC — needs to be priced, agreed in writing and signed off before you do the work.

A variation order should state: what is changing, what the fixed-price impact is (or a provisional sum if the cost is genuinely unknown), and whether it affects the programme. Both parties sign before the work starts. Builders who do variations on a handshake and invoice for them later find those invoices disputed.

If a client asks for a variation verbally on site, it is fine to acknowledge it and say you'll get the variation order over before the work is done. Do not start the work first. The variation order is your protection.

Why Builders Get Under-Paid: The Most Common Quoting Mistakes

The most frequent reasons builders end up doing work for less than it cost them are not lazy pricing — they're items that get forgotten or underestimated:

• Waste disposal and skip hire: a 6-yard skip in 2026 costs £250–£450 depending on area. A full extension will burn through several. Include every one.
• Scaffolding: for anything more than single-storey, you need scaffold. Price it in. Do not leave it as a "we'll sort it" item — get a quote from your scaffolding contractor and add it to the estimate.
• Plant hire: excavator hire, dumper hire, concrete pump — all have daily or weekly rates that add up fast.
• Building control fees: vary by project but typically £500–£2,000+ for a full-plans application on an extension. If you're managing the build control process, include this or make clear it is excluded.
• Structural engineer fees: required for load-bearing work, extensions, loft conversions. £500–£2,000 depending on complexity. Again, include or explicitly exclude.
• Underestimating groundworks: this is where most fixed-price extension quotes bleed. Use a provisional sum unless you have genuinely investigated the ground.
• Sub-trade price increases: if your quote sits live for three months before a client signs, material costs and sub-trade rates may have moved. Include a quote validity period of 30–60 days.

A good rule of thumb: once you've built your cost estimate, add a contingency of 5–10% for a new build or complex project and make sure your overhead and profit margin sits on top of that, not inside it.