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.
Planning the work? Check what it usually costs, or work out your own estimate. The free quote form is at the top of this page.
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
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.
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.
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.
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.
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.
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.
Compare Bathroom Quotes That Won't Fail at Year 7
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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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