Of all the trades, builders produce the most complex quotes. An electrician quotes circuits and accessories. A plasterer quotes rooms and bags of plaster. A builder quotes a project that might span six or eight weeks, involve three or four different trades, require materials from half a dozen suppliers, need plant hire for a skip and a mixer, include groundworks that can't be fully scoped until you've dug, and carry a genuine risk of hitting something unexpected in a Victorian terraced house that was last touched in 1987.
It's not surprising that building quotes go wrong more often than quotes in any other trade. What is surprising is how little good quoting software exists that's actually designed for how builders work — particularly smaller builders and sole traders who are doing their own quoting without a QS or estimator behind them.
AccuQuote was designed with over 200 UK tradesmen — builders, electricians, plasterers, plumbers — who were all losing money the same way: quoting from memory while material prices kept moving. This guide covers why building quotes go wrong, what good quoting software needs to handle, and how to quote faster and more accurately in 2025.
Why Building Quotes Are Hard to Get Right
There are a few structural reasons why builders consistently struggle with quoting, beyond just "it's complicated":
Multi-trade coordination
Most building projects touch multiple trades — foundations and structure, first and second fix carpentry, plastering, electrics, plumbing, decorating. If you're managing subbies, you need their rates in the quote. If you're doing it all yourself across multiple disciplines, you need to price each phase correctly. Generic quoting software doesn't have a concept of "electrics phase" or "plastering phase" — it's just line items.
Unknowns and contingencies
Every experienced builder knows that the first thing you discover when you open a wall is something that changes the project. Buried pipework running through a structural wall. Damp behind the render. A joist that's half rotten. The question isn't whether there will be surprises — it's whether your quote accounts for them. Most don't. Most builders absorb these costs or have difficult conversations with customers at the worst possible moment.
Materials price volatility
Timber, plasterboard, insulation, cement, steel — all moved substantially in price between 2021 and 2024 and continue to fluctuate. A quote produced with prices from three months ago may already be wrong. If you're buying materials from Travis Perkins, Jewson, or BuildBase, you need current prices in your quote, not last year's.
VAT complexity
New builds attract zero-rated VAT on labour. Conversions and renovations are complex — sometimes reduced rate applies, sometimes not. If you're not VAT-registered and quoting a job where the customer is expecting to claim VAT back on a renovation, it's a conversation you want to have upfront, not at invoice stage.
The margin killer: In a BuildBase survey of small builders, the average project overrun on labour was 18% and on materials was 12%. That's not waste — it's unquoted scope. The fix isn't to work faster. It's to quote more accurately from the start.
What Builders Need from Quoting Software
A quoting tool that actually works for building projects needs to handle:
- Phased quoting. Break the project into phases — demolition and strip-out, groundworks, structure, first fix, second fix, finish — and price each phase separately. This gives the customer a clear picture of the project and gives you a framework for progress payments.
- Multi-trade line items. Labour should be priceable by trade: builder rate (£250–350/day), electrician subbie (£280–320/day), plumber subbie (£250–300/day), plasterer subbie (£200–260/day). These are different costs and should be shown separately.
- Plant hire and skip costs. A skip costs £250–400 in most of England depending on size and location. A mixer hire is £80–120/week from Brandon Hire or HSS. These always get forgotten.
- Contingency line. A 10–15% contingency on a building project is standard practice, not padding. Present it explicitly in the quote as a contingency line rather than burying it in labour margins. Customers who understand what contingency means don't argue about it — it's the ones who feel surprised by costs who cause problems.
- VAT treatment. Whether you're VAT registered or not, the quote needs to handle this correctly.
- Real materials pricing. From Travis Perkins, Jewson, Wickes, or Toolstation. Not made-up ballpark figures.
How AccuQuote Helps Builders Quote Faster
AccuQuote's AI is trained on the specific vocabulary and scope of building projects — not just generic trade work. On a site visit, the workflow is:
- Scan the relevant spaces. For an extension or loft conversion, scan the existing rooms and the proposed footprint. LiDAR captures floor areas, ceiling heights and wall dimensions that feed directly into material calculations.
- Describe the project by phase. Speak naturally: "Single-storey rear extension, 4 metres by 4 metres. Strip-out existing outbuilding. Concrete strip foundations. Block and beam floor. Cavity wall, standard brick to match. Flat roof with EPDM. First fix plumbing and electrics. Plasterboard and skim internally. UPVC bifold doors." AccuQuote breaks this into structured phases.
- Review and adjust. The app generates a phase-by-phase BOM with materials quantities and labour estimates. You adjust for site-specific factors — access, parking for the mixer, whether the customer is supplying the doors themselves.
- Add contingency and overhead. Set your contingency percentage (typically 10–15%) and overhead rate. These appear as named line items in the final quote.
- Output a professional PDF. The quote is structured by phase, shows materials and labour separately, includes contingency, and presents a clear total with VAT calculated correctly.
Example: Single-Storey Kitchen Extension Quote
Here's a worked example for a 4m x 4m single-storey rear extension in the East Midlands, with a flat EPDM roof, bifold doors, and full internal finish. This is a realistic scope for a 6-week project.
| Phase / Item | Supplier | Qty / Unit | Total |
|---|---|---|---|
| Phase 1 — Demolition & Groundworks | |||
| Skip hire (3 x 8-yard skips) | Local hire | 3 loads | £870 |
| Concrete (strip foundations, 1m deep) | Aggregate Industries / readymix | 3m³ | £480 |
| Labour — groundworks, 4 days | — | — | £1,100 |
| Phase 2 — Structure | |||
| Commons bricks (external skin) | Jewson / Ibstock Anglian | 1,800 | £720 |
| Dense concrete blocks (internal skin) | Jewson / Tarmac 7N | 180 | £216 |
| Cavity wall insulation (Knauf Frametherm 80mm) | Travis Perkins | 20m² | £180 |
| Wall ties, DPC, lintels | Toolstation | — | £140 |
| Labour — bricklaying, 6 days | — | — | £1,800 |
| Phase 3 — Roof | |||
| Flat roof joists (C24 47x175mm) | Travis Perkins | 16 lengths | £320 |
| OSB3 18mm deck | Travis Perkins | 8 sheets | £240 |
| EPDM membrane (4.5m x 4.5m) | Permaroof / Toolstation | 1 | £360 |
| Insulation — 100mm PIR board | Kingspan / Travis Perkins | 20m² | £440 |
| Fascia, soffit, guttering | Toolstation | — | £180 |
| Labour — roof, 3 days | — | — | £900 |
| Phase 4 — Internal Finish | |||
| Gyproc Wallboard (12.5mm, 1200x2400) | Travis Perkins | 18 sheets | £230 |
| Thistle MultiFinish 25kg bags | Travis Perkins | 12 | £174 |
| Plasterboard screws, jointing tape, beading | Toolstation | — | £55 |
| Labour — plasterboard & skim (subbie), 3 days | — | — | £750 |
| Bifold doors (UPVC, 2400 x 2100, white) | Customer supply / Anglian quote | 1 set | £1,400 |
| Door installation labour | — | — | £280 |
| Phase 5 — Services | |||
| First fix electrics (subbie, 1.5 days) | — | — | £420 |
| Second fix electrics + EIC | — | — | £380 |
| Plumbing — extend radiator circuit (subbie) | — | — | £320 |
| Materials & labour subtotal | £11,735 | ||
| Contingency (12%) | £1,408 | ||
| Overhead & profit (15%) | £1,971 | ||
| Total (ex. VAT) | £15,114 | ||
| Total (inc. 20% VAT) | £18,137 | ||
This is a realistic mid-range price for this scope in the East Midlands in 2025. Prices in London and the South East would be 25–40% higher. The point of presenting it this way isn't to publish a price guide — it's to show what a good builder's quote looks like. Every line is justified. The customer can see exactly what they're buying. There are no surprises at invoice time because everything that's going to cost money is in the document upfront.
Pricing Different Types of Building Work
Extensions (single and double storey)
Single-storey rear extensions in the UK typically run from £1,500–2,500/m² depending on spec, location and roof type. A flat-roof extension is cheaper than pitched. Add 20–30% for a full kitchen fit-out within the extension. Always price groundworks separately — they're the biggest variable.
Full house refurbishments
A typical full refurb (replaster, rewire, replumb, new kitchen and bathroom) on a 3-bed Victorian terrace runs £60,000–120,000 depending on spec and location. The key is phasing: structure and services first, then plastering, then second fix, then decoration. Trying to start decoration while services work is still live creates rework and bad feeling.
Garage and loft conversions
Loft conversions range from £35,000 (basic dormer with Velux rooflights) to £80,000+ (full hip-to-gable with full height headroom and en-suite). Garage conversions are simpler — typically £15,000–25,000 for a full habitable conversion with insulation, new floor, plastering, glazing and electrics. Always confirm permitted development vs. planning permission status before quoting.
Get Started with AccuQuote
Building quotes are too important — and too profitable to get wrong — to rely on rough mental arithmetic and spreadsheets. AccuQuote is designed for UK tradespeople who want to quote accurately, look professional, and win more of the right jobs at the right price.
AccuQuote was built by tradesmen who were tired of quoting from memory while prices moved under their feet. Start with three free quotes — no card required, no salesperson, no Calendly. Just download and try it.