Compare Bathroom Renovation Builders: How to Choose in 2026
Choosing the right bathroom builder is a 9-point check, not a price race. The cheapest quote almost always misses TrustMark accreditation, Part P electrical sign-off, WRAS-approved plumbing, or a stage-payment schedule. Use the framework below to filter the four quotes you should always collect — and walk away from the two that hide the gaps.
Bathroom Builder Quote Tiers — What the Price Tells You
A 6 m² family bathroom in 2026 should land between £6,500 and £14,000 fitted (excluding sanitaryware). The cluster of quotes you receive is itself diagnostic — here is what each tier signals.
Too low to cover tradespeople properly. Usually one fitter doing electrical & plumbing without Part P / WRAS — illegal & voids your insurance.
FMB / TrustMark fitter, separate Part P electrician, written warranty, mid-range tile and sanitaryware. Best value tier.
Get quotes →Bespoke tiling, large-format porcelain, walk-in wet rooms, brassware spec, in-house electrician + plumber, design service.
The 9-Point Bathroom Builder Comparison Checklist
| Check | What "Pass" Looks Like | Common Fail |
|---|---|---|
| 1. TrustMark / FMB | Verified on trustmark.org.uk or fmb.org.uk | Logo on website, no membership number |
| 2. NICEIC Part P | Separate electrician with current Part P | "My fitter does the lights" |
| 3. WRAS plumber | Gas Safe (boiler) & WRAS-approved fittings | Push-fit only, no scheme number |
| 4. Insurance £2m+ | Public liability cert, named on quote | "I have insurance" — no document |
| 5. Fixed-price quote | Itemised, signed, dated, valid 30 days | Daywork rate or "ballpark" |
| 6. Stage payments | Deposit + 2-3 milestones, never >30% upfront | 50%+ deposit demanded in cash |
| 7. Written warranty | Min 2-year workmanship + manufacturer parts | Verbal "any issues just call" |
| 8. Recent references | Three local bathrooms in last 6 months, photos & phone | "Lots of happy customers" only |
| 9. Building Control | Notifies BC for electrics or moving WC waste | "Not needed for bathrooms" — false |
10 Questions to Ask Every Bathroom Quote
- Will you provide a fixed price or a daywork rate? Fixed only — daywork is a blank cheque.
- Who is doing the electrics and are they Part P registered? Should name a separate trade and accreditation number.
- Are your plumbing fittings WRAS-approved? Required by Water Regs — non-WRAS pipework can void insurance.
- What's in your warranty and what voids it? A serious builder hands you a printed warranty card.
- Can I see three recent local bathrooms? Phone numbers, not just photos.
- What's your stage payment schedule? Anything >30% upfront is a red flag.
- Who removes the spoil and old suite? Should be included; "extra skip cost" is a common upcharge.
- What allowance is in the quote for tiling? A specific £/m² figure, not "tiles supplied separately".
- How long is the on-site programme? Standard family bathroom is 7-12 working days; faster than 5 cuts corners.
- What's your contingency policy on hidden defects? Should be a written agreed hourly rate, not "we'll see".
Quote-Stage Red Flags You Can Spot in 5 Minutes
- VAT not shown separately or "cash discount" offered
- No company number on the quote letterhead — sole trader operating without limited liability
- Logo claims (Which? Trusted Trader, FMB) without a verifiable membership number
- Quote written in WhatsApp messages, not on letterhead
- Refusal to provide a written specification with brand and model numbers for sanitaryware and brassware
- Demand for cash payments only, or for the full balance before snagging
- "Lifetime guarantee" with no underwriter — meaningless if the firm folds
Comparing Bathroom Builders FAQ
How many quotes should I get for a bathroom renovation?
Three to four. Less and you can't spot outliers; more and you waste time. Reject the highest and lowest, then compare the middle two on spec, not price.
What accreditations should a UK bathroom builder hold in 2026?
TrustMark or FMB for the main contractor, NICEIC (or equivalent) Part P for the electrician, and WRAS approval for plumbing fittings. Gas Safe for any boiler work.
Is a Which? Trusted Trader badge enough?
It's a useful signal but not a substitute for TrustMark/FMB plus the trade-specific accreditations. Always verify the membership number directly on the scheme website.
Should I pay a deposit upfront?
A deposit of 10-25% to secure materials is normal. Anything above 30% upfront is a red flag — reputable builders use stage payments tied to completion milestones.
How long should a bathroom renovation take?
Standard family bathroom: 7 to 12 working days on site. Wet rooms or full re-plumbs: 12 to 18 days. Quotes promising 4-5 days are cutting corners on tiling cure time or first-fix testing.
Do bathroom builders need Building Control approval?
Yes for new electrical circuits (Part P) and for moving the WC waste pipe more than 1.5 m. Many bathroom-only fits notify under a Competent Persons Scheme — the builder should explain which.
Get Vetted Bathroom Builder Quotes — Free
We pre-screen every BestBuilders firm against the 9-point checklist. Tell us your post-code and bathroom size — get up to four written, comparable quotes from accredited fitters, typically within 4 working days.
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