7 Warning Signs Your Builder Is Overcharging (And What to Do About It)

The quote lands in your inbox. You open it. Scroll to the total. £92,000.

Your chest tightens. Is that normal? Are they taking advantage? You've got nothing to compare it to. The builder seemed nice enough. But ninety-two thousand pounds?

In short: The clearest signs are a quote significantly above regional benchmarks with no explanation, a labour-to-materials ratio above 60%, vague line items, and pressure to pay large deposits before work begins.

That nagging feeling - somewhere between suspicion and helplessness - is why you're here. So let's talk about it honestly.

The truth about "overcharging"

Sometimes builders are overcharging. Sometimes they're pricing work fairly and you're just experiencing sticker shock. And sometimes the quote that feels expensive is actually comprehensive, while the "good value" one is full of hidden gaps.

The problem is telling the difference.

Here's what we're going to do. We'll walk through seven concrete warning signs that suggest a builder might be taking the piss. Each one comes with real examples, real numbers, and what you should actually do about it.

But first, an important distinction.

High price vs overcharging: not the same thing

A £95,000 quote isn't automatically a rip-off. If it's for a 30m² double-storey extension in Berkshire with bi-fold doors and underfloor heating, that might be bang on.

Overcharging means you're being charged significantly more than the work is worth - either through inflated margins, padded costs, or intentionally vague scope that leads to extras. Our guide on whether your builder's quote is too high covers fair pricing benchmarks in detail.

Sometimes high prices are justified:

• Premium materials cost more
• Experienced builders with proper insurance and qualified staff charge more
• London and the South East are just more expensive
• Complex work (structural steel, listed buildings) costs more

So don't panic at a big number. Panic when the number doesn't match the work. That's what we're checking for.

Right. Let's get into it.

Warning sign 1: No breakdown - just a single lump sum

What it looks like:

"Supply and install rear extension as discussed: £78,000"

That's it. One line. No materials, no labour split, no trade-by-trade breakdown. Just a number.

Why it's a red flag:

A single lump sum means you can't see where the money's going. You've no idea whether the brickwork is priced fairly, whether the electrician's rate is reasonable, or whether the builder's marking up materials by 10% or 40%.

It's not illegal. But it's opaque. And opacity protects the builder, not you.

Real example:

Builder quotes £68,000 as a single line item. Homeowner asks for a breakdown. Turns out £22,000 is for "labour and management" - that's 32% of the total. Industry standard is 15–20% for main contractor overhead and profit.

Once itemised, the real cost of the work was closer to £58,000. The builder was adding a 17% margin on top of already-marked-up labour.

What to do:

Ask for an itemised breakdown. Most builders will provide one if you ask. If they refuse or get defensive, that's a red flag on its own.

You don't need to see every screw and rawl plug. But you should see costs split by trade - groundworks, brickwork, carpentry, electrics, plumbing, roofing - and a clear line for main contractor overhead. See how to read a builder's quote for a section-by-section walkthrough.

If they won't show you, walk away.

Warning sign 2: Vague line items with no detail

What it looks like:

"Works as discussed: £12,000" "Making good and finishing: £8,500" "Additional works: £4,200"

Why it's a red flag:

Vague descriptions are the builder's escape hatch. "Works as discussed" could mean anything. When something crops up that wasn't explicitly listed, the builder can argue it wasn't part of "the discussion" and charge extra.

"Making good" is a favourite. It's construction-speak for tidying up, filling holes, painting over mess. But it's vague enough that it can be stretched to cover almost anything - or exclude almost anything.

Real example:

A homeowner was quoted "Decoration and making good: £3,800" for a loft conversion. When the job finished, the walls were plastered but not painted. The builder argued decoration meant "prep for decoration" and charged an extra £1,600 to actually paint the room.

Semantics? Yes. But £1,600 worth of semantics.

What to do:

Ask the builder to define each vague item. What does "making good" include? Does decoration mean primed walls or two coats of Dulux? Does "works as discussed" mean the written scope or the verbal chat over tea?

Get it in writing. If the builder says "don't worry, we'll sort it," that's not an answer. You need specifics before you sign.

Warning sign 3: Massive markup on materials you can price yourself

What it looks like:

You mention you'd like a specific kitchen - say, the Howdens Greenwich range in Cashmere. Trade price for that kitchen is around £3,200. The builder quotes "Supply and fit kitchen: £7,800."

Fitting a kitchen - first and second fix plumbing, electrics, tiling, worktop templating - is about £2,000–£2,500 labour. So the builder is charging £7,800 for £5,700 of work and materials.

That's a 37% markup.

Why it's a red flag:

A 10–15% markup on materials is normal. Builders have trade accounts, they handle delivery and storage, they take responsibility if something's damaged. Fair enough.

But 30–50% markups? That's taking the piss.

Real example:

A builder quoted £9,400 to "supply and fit bathroom suite." The homeowner later Googled the exact model numbers listed in the quote. The suite - bath, basin, toilet, taps, shower, tiles - came to £2,100 retail. Trade price would've been closer to £1,600.

Even allowing £2,500 for plumbing and tiling labour, the builder was charging £5,300 over cost. That's a 129% markup.

When challenged, the builder said the quote was "all-in" and included "project management." Maybe. But it wasn't explained upfront.

What to do:

If the quote lists specific products, Google them. Check Screwfix, Toolstation, or the manufacturer's site for rough pricing. Add 10–15% for trade markup and reasonable labour.

If the total's way off, ask the builder to separate materials and labour. A good builder won't mind. A dodgy one will get defensive.

Warning sign 4: Labour-to-materials ratio is way off

What it looks like:

Total quote: £85,000. Materials: £28,000. Labour: £57,000.

That's a 67% labour share. For most projects, labour should be 40–55% of the total cost. Anything above 60% suggests inflated labour rates or padded hours.

Why it's a red flag:

Unless you're doing something extremely labour-intensive - like hand-cutting a slate roof or restoring original sash windows - labour shouldn't dominate the budget that heavily.

Most residential projects are roughly 50/50 labour and materials, give or take 10%. If the split's drastically skewed, someone's numbers are off.

Real example:

Single-storey rear extension, 18m². Builder quoted £72,000 total: £48,000 labour, £24,000 materials.

Materials breakdown:

• Bricks, blocks, cement: £4,200
• Structural steel: £2,800
• Roof (EPDM, insulation, joists): £3,600
• Windows and bi-folds: £6,500
• Electrics and plumbing materials: £2,400
• Flooring and finishes: £4,500

Total: £24,000. Reasonable.

Labour breakdown:

• Groundworks: 8 days @ £350/day = £2,800
• Bricklaying: 15 days @ £280/day = £4,200
• Carpentry and roofing: 12 days @ £280/day = £3,360
• Plastering: 5 days @ £220/day = £1,100
• Electrics: £2,800
• Plumbing: £2,200
• Tiling and decoration: £3,000

Total labour at market rates: £19,460. The builder quoted £48,000.

Where's the extra £28,540? "Main contractor management and overheads." That's a 147% markup on labour.

What to do:

Check the labour-to-materials ratio. If it's heavily skewed, ask for a breakdown of labour by trade and by estimated days.

Standard day rates in 2026 (outside London):

• Groundworker: £250–£350/day
• Bricklayer: £250–£300/day
• Carpenter: £220–£280/day
• Plasterer: £200–£250/day
• Electrician: £200–£300/day
• Plumber: £200–£280/day

Main contractor overhead and profit: 15–20% of total cost is normal. 30%+ is steep.

Warning sign 5: No exclusions list (or a suspiciously short one)

What it looks like:

The quote runs to four pages. Detailed scope. Payment schedule. Terms and conditions. But no exclusions section.

Or there's one line: "Exclusions: structural engineer's design, building regulations fees."

Why it's a red flag:

Every quote should list what's not included. If it doesn't, you've no idea where the boundaries are. When something comes up mid-project, the builder can claim it was never in scope - and charge extra.

A short exclusions list isn't necessarily bad, but it's worth checking. A good builder will list 8–15 excluded items - not because they're trying to exclude things, but because they've thought carefully about what's in and what's out.

Real example:

Homeowner accepts a quote for £58,000 with no exclusions. Three weeks in, the builder says scaffolding wasn't included: "You're arranging that separately, yeah?" Homeowner wasn't. Scaffolding hire: £2,200.

Then skips. Not included. Four skips at £320 each: £1,280.

Then party wall agreement fees. Not mentioned. £1,400.

Then building regs inspection fees. Not in the quote. £680.

Total extras: £5,560. The "£58,000 quote" is now £63,560, and the homeowner's got no leverage because none of it was documented as included.

What to do:

Look for an exclusions section. If there isn't one, ask the builder to provide a written list of what's not covered. Our what a builder's quote should include post covers the full checklist. You can also use our Red Flags in Builder Quotes resource for a quick scan.

Items that should be clearly marked as included or excluded:

• Building regulations fees
• Party wall agreements
• Structural engineer's design and calcs
• Scaffolding
• Skip hire (and how many skips)
• Decoration (primer only, or full two-coat finish?)
• Landscaping and garden reinstatement
• Kitchen or bathroom supply (fit-only or supply-and-fit?)
• Utility diversions (gas, water, drains)
• Asbestos survey and removal (for older properties)

If any of these aren't mentioned, ask.

Warning sign 6: Day rates for big jobs (instead of fixed price)

What it looks like:

"Loft conversion: 6–8 weeks @ £1,200/week = £7,200–£9,600 plus materials."

Why it's a red flag:

Day rates are fine for small jobs. Hanging a door. Fitting a radiator. Repointing a chimney. Anything under £2,000.

But for anything bigger, day rates are a problem. The builder has no incentive to finish quickly. A six-week job drifts to eight weeks. Eight becomes ten. You're paying for time, not outcomes.

Fixed-price quotes incentivise efficiency. The faster the builder finishes (without cutting corners), the better their margin. That's alignment of interests.

Day rates do the opposite. The longer it takes, the more they earn.

Real example:

Builder quoted "4–6 weeks labour @ £1,400/week" for a garage conversion. Homeowner agreed, thinking it'd probably be five weeks. Four months later, the job still wasn't finished. The builder kept finding "unexpected issues" - some legitimate, some suspiciously convenient - and the labour bill hit £22,000.

A fixed-price quote for the same job from another builder: £16,500 including materials and labour.

What to do:

For any job over £5,000, push for a fixed price. If the builder won't quote fixed, ask why. The answer is usually one of two things:

1. "There are too many unknowns" - fair enough if it's a renovation with hidden issues. But then ask for a fixed price for the known work, with a provisional sum or hourly rate for unforeseen extras.

2. "I prefer day rates" - that's not a reason, that's a preference that benefits the builder at your expense. Walk away.

If you must accept a day rate (e.g. for investigative work or remedial repairs), agree a cap. "Day rate up to a maximum of £X, after which we renegotiate." That way you're not writing a blank cheque.

Warning sign 7: Quote is 40%+ above other quotes with the same scope

What it looks like:

You get three quotes for the same project. Builder A: £68,000. Builder B: £72,000. Builder C: £102,000.

Same house. Same drawings. Same spec. Same site visit.

Why it's a red flag:

A 5–15% spread between quotes is normal. Different overheads, different profit margins, different labour rates. That's fine.

But 40%+? Either Builder C has wildly inflated their price, or they've misunderstood the scope, or they've included things the others haven't.

All three are worth investigating.

Real example:

Three quotes for a kitchen extension. Builder A and B both quoted £64,000–£67,000. Builder C quoted £95,000.

Homeowner asked Builder C to break it down. Turned out they'd included:

• Full house rewire (not in the brief): £8,500
• New boiler and central heating (not asked for): £6,200
• Landscaping the entire back garden (just wanted the patio reinstated): £7,800

Remove those and Builder C's quote was £72,500 - still high, but within 12% of the others. The difference was scope creep, not overcharging.

But if Builder C hadn't been questioned, the homeowner might've just thought they were expensive and dismissed them. Or worse - accepted the quote and paid for work they didn't want.

What to do:

If one quote is drastically higher, don't just reject it. Ask the builder to explain the difference. Walk through their quote line by line. They might've included something valuable that the others missed. Or they might've misunderstood the scope.

If the explanation doesn't add up - "Well, we're just better quality" isn't an explanation - then yes, they're probably overcharging. But give them a chance to justify it first.

And if one quote is drastically lower, apply the same logic in reverse. What's missing?

When expensive doesn't mean overcharging

Before you accuse anyone of taking the piss, here are legitimate reasons a quote might be higher:

They've included more

Builder A quotes £58,000 but excludes scaffolding, skips, and decoration. Builder B quotes £67,000 and includes them. Builder B isn't more expensive - they're more comprehensive.

Always compare scope, not just totals.

Better materials

Aluminium windows cost 2–3× more than uPVC. Quartz worktops cost double what laminate does. Engineered oak flooring is pricier than vinyl.

If one builder has specced premium materials, the price will reflect it. That's not a rip-off, it's just a different spec.

Proper insurance and qualified staff

A builder running a legit operation - public liability insurance, employers' liability, CITB-registered workforce, proper site management - has higher overheads than a bloke with a van and a couple of mates.

Those overheads show up in the price. But they also show up in the quality of the work, the project management, and the likelihood of it finishing on time without drama.

You're not just paying for bricks and labour. You're paying for competence and accountability.

They've added contingency

Some builders pad the quote by 5–10% to cover unforeseen issues. Others quote lean and charge extras.

The padded quote looks more expensive upfront. But it might be cheaper overall if the "lean" quote gets hit with £8,000 of variations.

Ask directly: "Does this include any contingency, or will extras be charged separately?" The answer will tell you a lot.

What to actually do if you suspect overcharging

Right. You've spotted one or more of the warning signs above. The quote feels off. What now?

Step 1: Get comparisons

If you've only got one quote, you've got no frame of reference. The best defence is comparing multiple quotes using a structured method. Get at least two more - our guide on how many quotes to get for an extension explains why three is the minimum for meaningful comparison.

If all three come in around £65,000–£72,000 and one's at £95,000, you know which one's the outlier.

Step 2: Ask for a detailed breakdown

Politely ask the builder to itemise the quote. Most will comply. If they refuse, that's a red flag on its own.

You're not interrogating them. You're trying to understand where the money's going. That's a reasonable request.

Step 3: Check cost per m² against benchmarks

Divide the total by the floor area of the new build. Compare it to the benchmarks in our detailed cost guide.

If you're at £4,200/m² for a standard single-storey extension in Nottingham, something's off. If you're at £3,800/m² for a premium spec in Surrey, that's probably fair.

Step 4: Question the gaps

If materials seem inflated, ask for a materials/labour split. If labour's too high, ask for a breakdown by trade. If one quote is way higher than the others, ask the builder to explain the difference.

Good builders will walk you through it. Dodgy ones will get defensive or vague. And if you're already mid-project and worried about quality, learn how to check the quality of work yourself - poor workmanship is a stronger signal of a problem than price alone.

Step 5: Walk away if it doesn't add up

If the builder can't justify the price, won't provide a breakdown, or gets arsey when questioned, don't proceed. You don't owe them your business.

Trust your gut. If it feels wrong, it probably is. Before committing, run through our what to ask your builder checklist.

Quick sanity check: cost per m² benchmarks

Here's a fast way to check if you're in the right ballpark. These are 2026 averages for England and Wales, excluding VAT.

Adjust for region:

• London: add 25–40%
• South East: add 10–15%
• North East / Wales: subtract 10–20%

If your quote's within 15% of the benchmark, you're probably fine. If it's 30%+ over, dig deeper.

Full regional multipliers and detailed breakdowns in this guide.

FAQs

How do I know if my builder is overcharging?

Compare the quote to regional benchmarks (cost per m²), check for vague line items or missing exclusions, and get at least two other quotes for comparison. If one quote is 30–40% higher without clear justification, that's a warning sign.

What's a normal profit margin for a builder?

Main contractor overhead and profit typically runs 15–20% of the total project cost. Anything over 25% is on the high side unless there's a specific reason (very small job, complex project management, etc.).

Should I accept a quote based on day rates?

Not for large projects. Day rates remove the builder's incentive to finish efficiently. For jobs over £5,000, insist on a fixed price. If the builder won't provide one, ask for a capped day rate or walk away.

Is it rude to ask a builder to justify their price?

Not at all. You're spending tens of thousands of pounds. Asking for a breakdown or clarification is completely reasonable. Good builders expect it. Defensive or evasive responses are a red flag.

What if the cheapest quote is half the price of the others?

It's almost certainly missing scope. Check the exclusions, compare material specs, and ask what's not included. Cheap quotes rarely stay cheap once the missing items get added back in.

Can I negotiate a builder's quote down?

You can ask, but don't expect much movement. Builders price to their margins. If you want a lower price, remove scope - fewer finishes, cheaper materials, or exclude certain trades. Don't just ask for a discount; good builders will say no.

What's a reasonable deposit to pay upfront?

10–15% to secure materials and book the project is normal. Anything over 20% is a red flag. Never pay more than 30% before work starts, and never pay the final balance before the job's finished.

Get a second opinion in 30 seconds

If you want to skip the manual checks and just know whether your quote's fair, upload it to MyBuildAlly.

Our AI compares your quote against regional benchmarks, flags missing scope items, checks for vague descriptions, and tells you whether the pricing looks reasonable.

Takes about 30 seconds. A lot faster than spreadsheets and a lot cheaper than hiring a quantity surveyor. Not sure whether to check yourself or get professional help? We break down the AI quote checker vs quantity surveyor comparison too.