Tax Guide for Self-Employed Bathroom Fitters in the UK
What expenses can a self-employed bathroom fitter claim? CIS deductions, tools, tanking kits, subcontractor costs — with a worked tax calculation and refund.
Tax Essentials
- CIS Status
- Yes — 20% deduction
- Typical Income
- £30,000–£55,000
- HMRC Flat Rate
- £60/year (tools & clothing)
- VAT Threshold Risk
- Monitor turnover
- Industry Body
- Bathroom Manufacturers Association (BMA) / CIPHE
- Key Certifications
- CSCS card (Blue Skilled Worker or Gold Advanced Craft) · NVQ Level 2 in Fitted Interiors or Plumbing
Bathroom fitting falls under the Construction Industry Scheme (CIS) when you work for a contractor on new builds or refurbishments. Your contractor deducts 20% from your labour and sends it to HMRC, and you file Self Assessment at year end to reconcile your allowable expenses and claim any refund. Work paid directly by a homeowner — a one-off domestic bathroom replacement, for example — sits outside CIS, so no deduction applies, but the income is still taxable and reported on the same Self Assessment.
Bathroom fitters are multi-skill tradespeople — plumbing, tiling, and carpentry in one job. That breadth means a wider tool collection and higher material costs than single-trade workers, plus subcontractor costs for gas and electrical work you can't legally do yourself.
What You Can Claim
| Expense | Examples | Typical Annual Cost |
|---|---|---|
| Plumbing tools | Pipe cutters, pipe benders (Irwin Hilmor ~£80), basin wrenches, water pump pliers, silicone gun (Cox PowerFlow ~£25) | £100–£400 |
| Tiling tools | Manual tile cutter, wet tile cutter (Vitrex ~£250), diamond hole cutters, grout floats, mixing paddle | £100–£400 |
| Power tools | Makita or DeWalt SDS drill, multi-tool, jigsaw, angle grinder, cordless drill/driver | £200–£500 |
| PPE & workwear | Safety boots, knee pads, dust masks, safety glasses | £150–£300 |
| Vehicle costs | Van fuel, insurance, MOT, servicing, road tax | £4,000–£6,000 |
| Materials & consumables | Pipes, fittings, silicone, sealant, adhesive, grout, tanking kits (~£130–£180 each) | £500–£2,000 |
| Trade account purchases | Wickes, Victorian Plumbing, Bathstore, Trade Centre Plus, Screwfix, Plumbase | Included in materials |
| Subcontractor costs | Gas Safe engineer for boiler/gas work, Part P electrician for bathroom circuits | £300–£1,500 |
| Insurance | Public liability, tool cover | £80–£250 |
| Training & certifications | CSCS card renewal, NVQ assessment fees, Mira/Triton shower installer CPD | £100–£500 |
| Phone & apps | Mobile contract (business portion), job management apps | £150–£300 |
| Accounting fees | Tax return preparation, bookkeeping | £150–£400 |
Tanking and Waterproofing
Wet rooms and walk-in showers need proper waterproofing. A tanking kit (primer, membrane, sealing tape) costs £130–£180 per bathroom. If you buy these for jobs where they're not supplied by the client, they're fully deductible.
Subcontractor Costs: Gas and Electrics
You can't connect gas appliances or do notifiable electrical work in a bathroom without separate certification. If you include a Gas Safe engineer or Part P electrician in your quote and pay them directly, their cost is a deductible business expense. Bathrooms are classified as "special locations" for electrics, so most wiring work requires a qualified electrician.
HMRC Flat Rate Alternative
HMRC allows a £60/year flat rate deduction for tools and specialist clothing. For bathroom fitters, knee pads and tile cutters alone exceed this — claim the real figures with receipts.
Expenses You Can't Claim
- Commuting to a regular workplace — travel to the same location for over 24 months isn't deductible. Travel to different customer bathrooms is deductible.
- Everyday clothing — jeans and trainers don't qualify. Only specialist PPE counts (safety boots, knee pads, dust masks)
- Your original fitting qualification — your initial NVQ isn't deductible. Only renewals, upgrades, and CPD count
- Fines and penalties — parking tickets, PCNs, late-filing penalties
- Food and drink — unless you're working away from your normal area overnight
Example: How Much Tax Does a Bathroom Fitter Pay?
Claire works as a self-employed bathroom fitter through CIS. Here's her 2025/26 tax year:
| Item | Amount |
|---|---|
| CIS income (gross) | £40,000 |
| CIS deducted (20%) | £8,000 |
| Allowable expenses | £7,500 |
| Taxable profit | £32,500 |
| Income Tax (after £12,570 personal allowance) | £3,986 |
| Class 2 NI (profits above £6,845 SPT) | £0 |
| Class 4 NI (6% on £12,570–£50,270) | £1,196 |
| Total tax + NI due | £5,182 |
| CIS already deducted | £8,000 |
| Refund due | £2,818 |
For 2025/26, Class 2 NI is treated as paid once profits exceed the Small Profits Threshold of £6,845 — Claire's profit is well above this, so she owes nothing. Without claiming expenses, her refund would be around £868. Claiming expenses adds roughly £1,950 to her refund. You can claim back your CIS deductions through your Self Assessment return.
Record Keeping Tips
- Save tanking kit and material invoices — waterproofing costs £130–£180 per bathroom. Keep invoices with the job address for each install
- Track subcontractor payments — Gas Safe engineer and electrician invoices are deductible. Record the job, date, and amount for each subcontractor you pay
- Keep separate receipts for plumbing and tiling supplies — pipes, fittings, adhesive, and grout often come from different suppliers. Photograph thermal receipts from builders' merchants the same day
- Save your CIS payment statements — you need these to reclaim the 20% deduction. Chase your contractor for missing ones before 31 January
- Log every job and journey — note the customer address and mileage for each bathroom install. Most fitters work at a different property each week
Key Deadlines
| Deadline | What |
|---|---|
| 5 April | Tax year ends — finalise your income and expense records |
| 31 January | File Self Assessment and pay any tax owed (or receive your refund) |
| 31 July | Second payment on account (if applicable) |
If this is your first year, register for Self Assessment by 5 October after the tax year ends.
VAT Threshold
With day rates of £200–£350, experienced bathroom fitters working steadily can approach the £90,000 VAT threshold (2025/26) — especially those who supply bathroom suites alongside labour. At £275/day for 48 weeks, that's £66,000 from labour alone. Add material supply through trade accounts at Wickes or Victorian Plumbing and your turnover climbs fast. Monitor your rolling 12-month total, which is based on turnover, not profit.
Frequently Asked Questions
How much tax does a self-employed bathroom fitter pay?
A bathroom fitter earning £40,000 gross with £7,500 in allowable expenses pays around £3,986 in Income Tax plus £1,196 in Class 4 National Insurance for the 2025/26 tax year. Class 2 NI is £0 because profits exceed the £6,845 Small Profits Threshold. If your contractor has already deducted £8,000 under CIS, you'd be due a refund of about £2,818 once your Self Assessment is filed.
Do bathroom fitters need to register for CIS?
Yes — if you fit bathrooms on new builds or major refurbishments for a contractor, the work falls under CIS and the contractor must deduct 20% from your labour. Pure domestic work paid directly by the homeowner is outside CIS. Register as a subcontractor to avoid the 30% unregistered rate, and split materials and labour clearly on your invoices — CIS only applies to the labour portion.
Can I claim tile cutters, tanking kits, and shower installation training on tax?
Yes. Wet tile cutters (around £250), tanking kits (£130–£180 per bathroom), and CPD courses for products like Mira or Triton showers are all allowable expenses. Initial qualifications like your first NVQ aren't deductible, but renewals, upgrades, and product-specific training to keep your skills current all qualify.
Is my Victorian Plumbing or Wickes trade account spend tax-deductible?
Material purchases from Victorian Plumbing, Wickes, Screwfix, or Plumbase for jobs you're billing the customer for are fully deductible. Keep the VAT invoice for each transaction — trade accounts make this easier because they email statements monthly. Don't claim items bought for your own home, even if billed through the trade account.
How do I claim back CIS deductions as a bathroom fitter?
File your Self Assessment return between 6 April and 31 January after the tax year ends. Enter your gross CIS income and the total deducted (from your contractor's payment statements) — HMRC offsets the deductions against your tax bill and refunds the difference. Most bathroom fitters see their refund within 4–8 weeks. See the full CIS refund timeline for what to expect.
This guide is for informational purposes only and does not constitute tax, legal, or financial advice. Tax rules change frequently. Always verify current requirements on GOV.UK or consult a qualified accountant for your specific situation.
Official Sources
- Expenses if you're self-employed — GOV.UK
- Construction Industry Scheme — GOV.UK
- Simplified expenses for vehicles — GOV.UK
- Self-employed National Insurance rates — GOV.UK
- Check if you need to register for VAT — GOV.UK