Plasterer Self-Employed Tax UK 2026/27: Materials, CIS and Day Rates
Self-employed plasterers typically work under CIS for building contractors, with materials and hire equipment forming the bulk of deductible costs. Here's a full worked example for 2026/27.
Worked Example: £38,000 Turnover, Mixed CIS and Domestic Work
Self-Employed Tax Calculator
Calculate income tax, Class 2 and Class 4 National Insurance for self-employed and sole traders for 2025/26.
Self-employed tax calculatorGross income: £38,000 (£26,000 CIS subcontract, £12,000 direct domestic jobs)
CIS tax withheld at source (20% of £26,000): £5,200
Deductible expenses:
| Item | Cost |
|---|---|
| Plaster, beading, PVA, jointing compound | £5,600 |
| Spray plastering machine (AIA) | £1,600 |
| Hand tools (trowels, floats, hawks) | £320 |
| Vehicle running costs | £3,400 |
| Public liability insurance | £280 |
| Accountancy | £280 |
| Total expenses | £11,480 |
Taxable profit: £38,000 − £11,480 = £26,520
Income tax: (£26,520 − £12,570) × 20% = £2,790
Class 4 NI: (£26,520 − £12,570) × 6% = £837
Total tax and NI due: £3,627, against which £5,200 already withheld via CIS is credited — a refund of roughly £1,573 in this scenario.
Materials: Who Pays Determines the Deduction
| Job type | Who buys materials | What you deduct |
|---|---|---|
| Labour-only subcontract for a builder | Contractor/builder | Nothing — you have no material cost to claim |
| Labour-plus-materials subcontract | You | Full materials cost |
| Direct domestic job | Usually you (unless agreed otherwise with the homeowner) | Full materials cost |
Getting this distinction right on each job matters both for accurate expense claims and for setting prices that properly reflect whether materials are included.
CIS scheme guideDeductible Expenses Checklist
- Plaster, jointing compound, beading, PVA and other materials you buy
- Spray plastering machine, mixer (via AIA)
- Hand tools: trowels, floats, hawks
- Vehicle: mileage rate or actual running costs (pick one method, use consistently)
- Public liability insurance
- Accountancy and CIS deduction statement tracking
Registering and Filing
Register for Self Assessment and, if subcontracting for CIS contractors, for CIS itself. Keep CIS deduction statements and separate records for domestic (gross) income, and file your Self Assessment return by 31 January following the end of the tax year.
Frequently asked questions
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