Outsourced finance director for construction firms

A part-time finance director for builders, contractors and specialist subcontractors: job costing, work in progress valued every month, CIS and the VAT reverse charge planned into the cash flow, and retentions tracked until they are paid. Peter Allen, Buzz’s Financial Director, from £2,000 + VAT a month.

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For construction firms

Job costing against the estimate
Work in progress valued monthly
CIS and reverse charge in the forecast
Retentions tracked to release
Quarterly board meeting with Peter

See the finance director service

A job from tender to final account

Every live job has its own budget, its own cost to date and its own place in the cash flow forecast.

The Buzz finance team posts the costs to each job in Xero every week. Peter reads the jobs together at the quarterly board meeting.

Each job, from start to finish

The same four stages on every contract, in the monthly board pack.

Tender

The estimate split into labour, materials, plant and subcontract, so the job is costed against it from the first week.

Stage payments

A construction contract of 45 days or more gives a right to stage or periodic payments (Housing Grants, Construction and Regeneration Act 1996, section 109). The forecast carries each application and its due date.

Work in progress

Each month, cost to date compared with the value of work done on every live job, so the monthly profit matches the work on site.

Final account and retention

The retention held by the client recorded as owed to you, with the date each part is due, and chased on that date.

Cash on a £10,000 application

A subcontractor’s application for £10,000 does not put £10,000 in the bank.

The contractor holds back the retention and deducts CIS from the labour. Contractors do not take CIS from materials the subcontractor paid for, or from VAT (GOV.UK, CIS). The forecast shows the cash that arrives, the CIS credit against your tax and the retention due later.

One application from a subcontractor

Application: £6,000 labour, £4,000 materials: £10,000
Retention held at 5%: −£500
CIS at 20% on the £6,000 of labour: −£1,200
Paid into the bank: £8,300

The £1,200 counts towards your tax and National Insurance bill. The £500 arrives when the retention is released.

An illustrative example with invented figures. The contractor accounts for the VAT under the domestic reverse charge.

CIS and retentions

Under CIS a contractor deducts 20% from a registered subcontractor’s payments and 30% if the subcontractor is not registered. A subcontractor with gross payment status is paid in full (GOV.UK). A contractor files a CIS return by the 19th of each month, with a £100 penalty for a return one day late (GOV.UK).

The VAT domestic reverse charge has applied to most building and construction services between VAT-registered businesses since 1 March 2021 (GOV.UK). A subcontractor under the reverse charge stops receiving VAT from the contractor, which changes the cash the business holds between VAT returns.

In March 2026 the UK Government proposed a ban on retention payments under construction contracts, and will consult on how the ban is put in place (UK Government, late payment consultation response). Until then, retentions owed to you sit in the forecast as cash due on a date.

Northern Ireland firms can read our CIS guide for Northern Ireland.

Peter Allen, co-founder and Financial Director of Buzz Accounting

Your finance director is Peter Allen

Peter is Buzz’s co-founder and Financial Director, with more than 20 years’ experience.

He writes the one-page plan with you, owns the job-by-job forecast and the KPI dashboard, and runs your quarterly board meeting. The Buzz finance team does the weekly bookkeeping, payroll and VAT in Xero.

Book a call with Peter Meet the team

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Questions from construction firms

Do you file our CIS returns?

The Buzz finance team can file CIS returns. CIS is priced separately and confirmed in writing before work starts.

How do you value work in progress?

For each live job we compare the cost to date with the value of the work done, using your applications, valuations and the cost records in Xero, and put the result into the monthly management accounts.

Are retentions being banned?

In March 2026 the UK Government proposed a ban on retention payments under construction contracts and said it will consult on how the ban is implemented. Until a ban takes effect, retentions in your contracts still apply.

How much does a part-time finance director cost?

From £2,000 + VAT a month. The fee includes the day-to-day finance work as well: weekly bookkeeping in Xero, payroll and expenses, VAT returns, a monthly board pack, customer invoicing and chasing, supplier payments and cash monitoring. The fee is confirmed in writing before work starts.

Talk to us about a finance director for your firm

Tell us about the business and what you need. A named person replies within one working day.

Book a call with Peter The finance director service

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