Shower Installer
Tax & MTD Guide

Fitting showers is a low-overhead, high-skill trade, and the tax that goes with it has one feature that catches almost every installer out: the Construction Industry Scheme. If you work for a builder, a bathroom company or a main contractor, money has already been taken off your pay before it reaches you. That 20% deduction is not a tax you have lost; it is tax paid in advance, and for most subcontractors it means a refund is waiting at the end of the year, not a bill.

This guide is built around how a shower installer actually earns and spends: CIS deductions and the refund they create, the specific tools, materials, van and PPE costs that make up your deductions, the VAT reverse charge that trips up so many trades, and the record-keeping habits that turn a stressful January into a five-minute job. Get the basics right and you keep more of what you fit.

How Tax Works for a Self-Employed Installer

As a sole trader you pay Income Tax on profit, which is your total income minus allowable expenses, not on the full amount you invoice. For 2025/26 the personal allowance covers the first GBP 12,570, then you pay 20% to GBP 50,270, 40% to GBP 125,140 and 45% above, with the personal allowance tapering away between GBP 100,000 and GBP 125,140 to create an effective 60% band. Class 4 National Insurance is 6% on profit between GBP 12,570 and GBP 50,270 and 2% above, while Class 2 NIC is settled through Self Assessment.

Scottish installers pay Scottish Income Tax on profit through six bands (19%, 20%, 21%, 42%, 45% and a 48% top rate) and carry an S-prefixed tax code, while National Insurance stays UK-wide. Welsh installers have a C-coded tax code at rates currently matching the rest of the UK. If your code looks wrong, perhaps because CIS deductions or a part-time PAYE job have distorted it, run it through the tax code checker.

CIS: Deductions and the Refund You Are Probably Owed

If you fit showers for a contractor rather than directly for the householder, your work almost always falls under the Construction Industry Scheme. Before paying you, the contractor verifies your status with HMRC and deducts a percentage from the labour element of your invoice.

The crucial point is that CIS is deducted from your turnover, before any expenses come off. Your actual tax is calculated on profit, which is far lower once tools, van, materials and other costs are deducted. The gap between the 20% taken at source and the smaller amount you genuinely owe is your refund. Always keep every CIS deduction statement (payslip) the contractor gives you, because that is your proof of tax already paid. Our CIS subcontractor guide explains verification, gross payment status and the refund process in full, and the CIS tax calculator shows roughly what you should expect back.

Allowable Expenses for Shower Installers

An expense is allowable when it is incurred wholly and exclusively for the business. For an installer the list is dominated by tools, materials, PPE and vehicle costs. Claiming them properly is what turns those CIS deductions into a refund.

Van and Mileage in Detail

Your van is usually one of the biggest deductions. You can use HMRC's simplified mileage rate of 45p per business mile for the first 10,000 miles and 25p after that, which needs only a mileage log, or you can claim a fair business proportion of the actual running costs: fuel, insurance, road tax, servicing, repairs, tyres and finance interest. Pick one method per vehicle and stick with it for that van. A high-mileage installer covering a wide patch often does better on actual costs, while someone working mostly local can find simplified mileage simpler and just as generous. Either way, travel between jobs counts, but ordinary commuting from home to a regular fixed workplace does not.

Tools and the Annual Investment Allowance

Buy a wet saw, an SDS drill or a new van outright and you can usually deduct the full cost in the year of purchase under the Annual Investment Allowance, rather than spreading it over years. Hand tools, consumables and protective gear are claimed as ordinary running costs. Keep receipts for everything, including the small stuff bought from the merchant on the way to a job, because a fortnight of silicone, blades, spacers and fixings adds up to a meaningful deduction over a year.

What You Cannot Claim

The private share of dual-use costs must come out: your phone, your van and any tool used at home for personal jobs. Everyday clothing is not allowable even if you only wear it for work, though branded workwear and genuine PPE are fine. Fuel and mileage for the school run or weekend trips are private. And meals are only allowable in limited circumstances, not as a daily lunch on site.

Record-Keeping That Survives MTD

The installers who get the biggest refunds are simply the ones who keep the best records. Three habits cover almost everything:

• Bank everything through one account. A dedicated business account makes income and expenses obvious and keeps your private spending out of the figures.
• Photograph receipts as you get them. Merchant tickets fade and fall out of the van. Snap them the moment you are paid or you pay, and the figure is captured before it is lost.
• Log your CIS statements and mileage. File every CIS deduction statement and keep a running mileage note. These two records are what unlock your refund and your van claim.

Do this and the leap to digital record-keeping under MTD is barely a change, because you are already capturing each transaction as it happens rather than reconstructing the year from a shoebox in January.

Worked Example: A Shower Installer on GBP 45,000

Take a CIS subcontractor fitting showers and bathrooms for local builders, invoicing GBP 45,000 of labour for the year, with 20% deducted at source.

Income: GBP 45,000 (labour, CIS deducted)

CIS already deducted at 20%: GBP 9,000

Allowable expenses:

• Power tools, wet saw and tile cutter (AIA, claimed in full): GBP 2,200
• Sealant, grout, adhesive, fixings and consumables: GBP 1,400
• PPE and workwear: GBP 350
• Van running costs (actual, business share): GBP 4,200
• Public liability insurance: GBP 450
• Phone, quoting apps and admin: GBP 400
• Accountancy and bank fees: GBP 500
• Total expenses: GBP 9,500

Taxable profit: GBP 45,000 minus GBP 9,500 = GBP 35,500

Income Tax: GBP 35,500 minus GBP 12,570 = GBP 22,930 at 20% = GBP 4,586

Class 4 NIC: GBP 22,930 at 6% = GBP 1,376

Tax and NIC due: GBP 5,962. CIS already paid: GBP 9,000. That leaves an estimated refund of around GBP 3,038, because the 20% was taken off the full GBP 45,000 while the real liability is calculated on the GBP 35,500 profit. Run your own figures through the CIS tax calculator or the sole trader tax calculator to sanity-check what you are owed.

VAT and the Domestic Reverse Charge

You must register for VAT once taxable turnover passes GBP 90,000 in any rolling 12-month period. Once registered, construction trades meet the domestic reverse charge, which changes who accounts for the VAT. When you supply CIS-covered labour to another VAT-registered business in the construction chain, you do not add VAT to your invoice; the contractor accounts for it on their own return instead. You note on the invoice that the reverse charge applies and that the customer must account for the VAT.

The reverse charge does not apply when you bill a homeowner directly, an end user who is not a VAT-registered business in the construction chain. There you charge VAT in the normal way. Either way, registration lets you reclaim VAT on tools, the van, materials and overheads, which for a tool-heavy trade can be worth having even before you hit the threshold. If most of your work is for contractors, the reverse charge also means you are no longer holding the VAT cash, which removes a common cash-flow headache.

MTD for Income Tax: What Changes for Installers

Making Tax Digital for Income Tax Self Assessment replaces the once-a-year return with quarterly digital submissions and a year-end finalisation. The thresholds are based on gross income before CIS deductions and expenses, not profit:

• April 2026: Combined self-employment and property income over GBP 50,000
• April 2027: Over GBP 30,000
• April 2028: Over GBP 20,000

For an installer this is the moment loose paperwork stops working. Instead of bagging up CIS statements and receipts for a January scramble, you record each invoice, deduction and material cost digitally as it happens and send HMRC a summary every quarter. Because the threshold is on gross income, a busy subcontractor turning over GBP 50,000-plus in labour is caught from April 2026 even though profit is far lower. Our guide to MTD for sole traders walks through what the quarterly rhythm looks like in practice.

Common Mistakes Shower Installers Make

Treating the CIS deduction as the final tax. It is an advance payment. Once expenses are deducted your real liability is lower, and the difference is a refund you must claim through Self Assessment.

Throwing away CIS statements. Without your deduction statements you cannot prove the tax already paid, and your refund stalls. Keep every one.

Forgetting the small merchant receipts. Silicone, blades, spacers and fixings bought across the year add up to a real deduction. Photograph the ticket every time.

Missing the van claim or mixing methods. Choose mileage or actual costs per vehicle and apply it consistently; do not claim both for the same van.

Ignoring the VAT reverse charge. Once registered, adding VAT to a contractor's invoice when the reverse charge applies creates a mess for both of you. Check whether your customer is an end user first.

People also ask

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