Accountant for Construction Tradespeople in the UK
If you're a builder, electrician, plumber or run a small construction outfit, your accountant needs to understand CIS deductions, the VAT reverse charge and the cash flow squeeze that comes with retentions and staged payments - not just file a return once a year and disappear.
CIS deductions and what they do to your cash flow
The Construction Industry Scheme means a contractor deducts tax from a subcontractor's payments before it reaches them, then pays that money to HMRC on the subcontractor's behalf. Registering under CIS gets you the lower standard deduction rate; staying unregistered means a higher rate is taken off every payment, which can hit cash flow hard if nobody flags it.
Those deductions are advance payments against your actual tax bill, not extra tax. If you're a sole trader, they get set against what you owe on your self-assessment return. If you run a limited company, they can be offset against PAYE, National Insurance or corporation tax due. A lot of tradespeople have deductions sitting with HMRC that should have come back to them months earlier, simply because nobody reconciled the CIS statements against the return.
The VAT reverse charge for construction services
For most standard and reduced rate construction work supplied between VAT-registered contractors, the reverse charge means the customer accounts for the VAT instead of the subcontractor charging it on the invoice. Get this wrong and you either under-declare VAT you should have charged, or you charge VAT you shouldn't have, both of which invite HMRC correspondence.
Getting invoice wording and VAT coding right from the first job matters more in construction than in most trades, because the reverse charge also changes how much cash actually lands in your account each month - money you might have budgeted as VAT you'd hold before paying it over no longer sits with you at all.
Employment status, retentions and staged payments
Whether the people working for you are employees, self-employed subcontractors, or labour-only subcontractors caught by CIS changes your tax and National Insurance exposure significantly. Getting this classification wrong is one of the more expensive mistakes a growing construction business can make, because HMRC can reassess status retrospectively.
On top of that, retentions and milestone billing mean there's often a real gap between raising an invoice and the cash actually arriving. An accountant who understands how construction contracts are billed can help you plan drawings and build up tax reserves as the work comes in, so you're not caught short when a tax bill falls due.
Sole trader or limited company for a construction business
Trading through a limited company gives you a layer of separation between your personal assets and the business, which matters on sites where damage or injury claims are a real risk. It can also be more tax efficient once profits pass a certain level, but it comes with extra obligations: corporation tax, a confirmation statement, and payroll if you pay yourself a salary.
The right structure depends on your actual numbers, not a rule of thumb, which is why it's worth having an accountant model both options against your real income before you decide. Pairing bookkeeping automation with a qualified chartered accountant reviewing the figures keeps this manageable without needing to hire in-house finance staff.
Frequently asked questions
What is CIS and do I need to register?
The Construction Industry Scheme applies to most mainstream construction operations where a contractor pays a subcontractor for work. If you're a subcontractor doing construction work for a contractor, you'll usually need to register, and registering gets you a lower rate of tax deducted from your payments than staying unregistered. A few professional services, like pure design or surveying work, sit outside the scheme, so it's worth checking whether your specific work is covered.
Can I claim back CIS tax I've overpaid?
Yes. CIS deductions are advance payments against your tax bill, not a final charge. If you're a sole trader, any excess comes back to you through your self-assessment return. If you run a limited company, you can offset CIS deductions against PAYE, National Insurance and corporation tax due, and reclaim what's left over. This only happens if someone is actually reconciling your CIS statements against what you owe, which is easy to miss if it's not being tracked month to month.
Should a tradesperson go limited or stay a sole trader?
It depends on your profit level, how much liability risk you're carrying on site, and how much admin you're prepared to take on. Sole trader status is simpler to run, but a limited company gives you personal liability protection and can be more tax efficient once profits grow. The only reliable way to decide is to have an accountant run both scenarios against your actual figures rather than following a generic rule.