Accountants for construction businesses in Winchester and Hampshire
CIS, reverse charge VAT, payroll and year-end handled properly, and monthly numbers that tell you which jobs are actually making money. Fixed monthly fee from £275, Xero included, and you deal directly with Chris Sullivan, an ICAEW Chartered Accountant based at Abbey Mill in Winchester.
From, per month, with your Xero subscription and CIS returns included
Chartered Accountant, member C011009337, not a call centre or a junior
Management accounts and a rolling cash-flow forecast, not just year-end
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Profitable on paper, short of cash in practice
Most construction businesses we talk to have the same three problems, and none of them show up in a set of year-end accounts.
The cash never matches the profit
You pay subcontractors on Friday, the main contractor pays you in 45 days, HMRC takes 20% off the top under CIS, and a retention sits on someone else's balance sheet for a year. The job was profitable. The bank account doesn't look like it.
You don't know which jobs make money
Turnover is up, the van is always out, and at the end of the year the profit is thinner than it should be. Without costs tracked by job, you can't tell whether the problem is pricing, materials, labour or one customer who never pays on time.
Compliance you can't quite see
CIS deductions on the wrong amount, reverse charge VAT applied the wrong way round, a subcontractor who HMRC would call an employee. Nobody tells you until the letter arrives.
A year-end accountant can't fix any of these, because they only see your numbers once a year. That is the gap Lumi is built for: an ICAEW Chartered Accountancy practice at Abbey Mill, Winchester, acting as construction accountant for builders, contractors and trades across Hampshire, with CIS, reverse charge VAT, payroll, management accounts and cash-flow forecasting on one fixed monthly fee.
Correct for the 2026/27 tax year · last reviewed October 2026 · Chris Sullivan ACA
What a construction accountant should actually be doing for you
Filing your accounts and corporation tax is the minimum. For a construction business it should also mean:
- Monthly CIS returns and subcontractor verification done before anyone gets paid.
- VAT returns where the domestic reverse charge is applied correctly on every invoice, in and out.
- Payroll that handles employees, the director and CIS subcontractors without mixing them up.
- Bookkeeping that separates labour, materials, plant and subcontractors by job, so your numbers mean something.
- Monthly management accounts you can read in ten minutes.
- A cash-flow forecast that shows next quarter's VAT and PAYE before they land.
- Someone who picks up the phone when a customer is 60 days late and you need to know whether you can still take on the next job.
Not sure whether your current accountant is giving your construction business enough support? Let's have a conversation →
CIS, VAT and payroll without the letters from HMRC
CIS returns, verification and deductions
If you pay subcontractors, you are a CIS contractor. That means verifying each subcontractor with HMRC, deducting 20% (or 30% if they're not registered) from the labour element only, filing a CIS300 return every month and issuing deduction statements. Miss a month and the penalty starts at £100.
We take the whole cycle on: verification, deduction calculations, the monthly return, statements for your subcontractors, and the bookkeeping behind it so CIS suffered and CIS deducted are never muddled. If you're a subcontractor yourself, we claim back the tax deducted from you through your payroll or year-end return, and we'll tell you honestly whether gross payment status is realistic before anything is applied for.
VAT and the domestic reverse charge
Since 2021, most VAT-registered construction work between businesses is reverse charged: you don't charge VAT to a contractor, they account for it themselves. New-build housing is zero-rated, some conversions are 5%, repairs are 20%, and an end user has to tell you in writing that they are one. Get it wrong and you either under-collect, over-pay, or have a subcontractor's invoice you can't reclaim VAT on.
We set Xero up so the right treatment is applied automatically, review the reverse charge position on every return, and check new clients' books for the errors we see most: VAT charged where it should have been reverse charged, and the other way round. Where cash accounting helps your cash flow, we'll say so.
VAT returns for construction →
Free toolNot sure about an invoice? Check it in 30 seconds with our CIS deduction & VAT reverse charge checkerEnter an invoice, get the deduction, the reverse charge answer and the wording the invoice needs. →Payroll, subcontractors and PAYE
Construction payroll is rarely just "staff". You might have two employees on PAYE, yourself on a director's salary, six subcontractors under CIS and a labourer who is somewhere in between. We run the payroll alongside the CIS returns so each person is treated the right way, pension auto-enrolment is handled, and the PAYE and CIS liabilities are reported together so you know what's due to HMRC on the 22nd.
If HMRC would see one of your subcontractors as an employee, we'll tell you before they do and help you put the arrangement on a sound footing.
Monthly numbers that tell you what to do next
Management accounts and job profitability
Each month you get a short set of accounts that answers the questions that actually matter: what did we invoice, what did each job cost in labour, materials, plant and subbies, what margin did each job make, what are overheads running at, who owes us money, who do we owe, and how much cash is in the bank after the VAT and PAYE that's coming.
We set your Xero up with a construction chart of accounts and job tracking from day one, so this isn't a spreadsheet exercise at year-end. It is how you find out that the extensions make 28% and the kitchens make 9% before you price the next one.
Cash-flow forecasting for construction
A rolling forecast built around how construction actually gets paid: applications and valuations, retentions, CIS deducted at source, subcontractors paid before customers, and VAT and corporation tax falling in lumps. We update it monthly with your real receipts and payments so you can see a shortfall in eight weeks' time rather than discover it on a Thursday.
It also answers the growth question honestly. Taking on a second crew, buying a digger rather than hiring one, or running three jobs at once can all be profitable and still drain cash for six months. The forecast shows whether growth is generating cash or consuming it, before you commit.
Want to know what your cash looks like three months out? Book a free 30-minute meeting →
Year-end accounts and tax for construction companies
We prepare your statutory accounts and corporation tax with the construction specifics handled properly: work in progress and long-term contracts valued correctly so profit isn't recognised too early or too late, retentions shown as what they are, accrued and deferred income on applications, CIS deductions suffered set against your liability, and capital allowances claimed on vans, plant, tools and scaffolding.
We also plan your tax rather than just report it. You'll know roughly what the corporation tax bill will be months before it's due, and we'll look at the most sensible way to take money out of the company through salary, dividends and pension, and prepare your director's Self Assessment alongside it.
Why construction businesses choose Lumi over a traditional accountant
Every accountant says friendly, professional and experienced. These are the differences you'd actually notice.
You deal with Chris
Not a client manager, not a junior, not a ticket queue. Chris Sullivan ACA is the person who sets up your Xero, reviews your returns and answers the phone. Direct line, email and WhatsApp.
Fixed monthly fee, known in advance
Construction packages from £275 a month, Xero subscription included. No hourly billing, no surprise invoice for a phone call.
Monthly, not annual
You hear from us every month with your numbers, and we talk properly every quarter about where the business is going.
Plain English
We'll explain what the numbers mean and what you might do about them, without the accountant-speak.
Construction is a specialism, not a tick-box
CIS, reverse charge, retentions, WIP, plant finance and employment status are handled in the context of your business, not looked up when they come up.
Built for growth
Sole trader to limited company, first employee, first six-figure contract, three jobs at once: we help you work out whether you can afford the next step, then set up the systems to handle it.
Owner-managed construction businesses across Hampshire
Typically limited companies or sole traders with subcontractors, turning over anywhere from £100k to around £2m. That includes builders and building contractors, groundworkers, electrical and plumbing contractors, roofing and renovation companies, and property maintenance firms.
Many of our clients are in Winchester, Eastleigh, Southampton, Romsey and Andover; we work by video, phone and site visit, so the postcode is rarely the deciding factor.
If you're a one-person subcontractor who only needs a tax return, we're probably more than you need, and we'll say so.
- A free 30-minute meeting. We talk through your business, your CIS and VAT position, and what you want from an accountant. No obligation.
- A fixed quote in writing. Usually within one working day.
- We handle the switch. We write to your old accountant for professional clearance, collect the records, and move or set up your Xero with a construction chart of accounts. You don't need to fall out with anyone.
- Monthly rhythm. Bookkeeping reconciled, CIS and VAT filed, payroll run, management accounts sent, forecast updated. Then a proper conversation each quarter.
Switching accountants is simpler than most people expect; most of the admin is ours, not yours.
Fixed monthly fees for construction businesses
All packages include your Xero subscription, statutory accounts and corporation tax, and CIS returns. Prices exclude VAT and are for businesses turning over up to £250k; larger businesses are priced within a published band on our pricing page.
Turnover over £250k, or something that doesn't fit a package? Request a quote and you'll have a fixed price within one working day.
Every construction client gets Xero configured with a construction-specific chart of accounts, separating labour, materials, plant and subcontractor costs by job, so your numbers are always meaningful.
- Xero with a construction chart of accounts (or your preferred software)
- Statutory accounts & corporation tax
- Director's payroll & personal Self Assessment
- Monthly bank reconciliation (up to 50 transactions)
- Email support
- Monthly CIS returns (as contractor)
- CIS deductions suffered reclaimed
- VAT reverse charge review
- Everything in Lite, plus advanced Xero
- Monthly bank reconciliation (up to 150 transactions)
- Quarterly VAT returns including the reverse charge
- Payroll for up to 5 people
- Email support
- Full CIS contractor & subcontractor management
- Employment status reviews
- Capital allowances & AIA
- Basic job costing reports
- Everything in Core
- Monthly management accounts
- Quarterly strategy & tax review meetings
- Unlimited phone support
- Project-by-project profitability reporting
- Rolling cash-flow forecast
- Retention tracking & management
- Plant & vehicle finance optimisation
- Payroll for a variable / subcontractor workforce
All prices exclude VAT.
A fixed price for your construction business, within one working day
Five quick questions you can answer from memory. Chris reads every request personally and replies with a written fixed monthly fee, not a range. No call needed unless you want one.
Construction accountant FAQs
Talk to a construction accountant in Winchester
Thirty minutes, no obligation, no jargon. We'll look at your CIS and VAT position, talk about where the cash goes, and tell you honestly whether we'd be a good fit.
Or call Chris on 01962 435112 · info@lumiaccountancy.co.uk · Abbey Mill, Winchester SO23 9LH
Construction accountancy guides
Plain-English reads on the issues that catch construction businesses out.
