CIS accounting

CIS compliance at scale for housebuilders.

A housebuilder running two or three active sites will typically engage 20 to 50 subcontractors simultaneously across groundworks, brickwork, carpentry, roofing, first fix and second fix. Every one of those subbies must be verified before the first payment. Every month's CIS300 must be filed by the 19th. Every payment triggers a deduction statement obligation. In stop months, nil returns are now mandatory from 6 April 2026. At that volume, the CIS compliance cycle is a full administrative workstream in its own right. The April 2026 anti-fraud rules make the due-diligence requirement at each verification event equally non-negotiable: one poorly documented subcontractor relationship is now enough to trigger GPS revocation.

Book a free call CIS refund service

£100

Penalty on day one for a late CIS300 (including nil returns)

20%

Knowledge-based penalty on payments under FA 2004 s.62A (April 2026)

Due-diligence steps required before each subcontractor payment

The specific challenges

What makes housebuilders accounting different.

Verification at scale across a rotating subcontractor pool

Housebuilders rarely work with the same subcontractor pool from one site to the next. New groundworkers for a new phase, different bricklayers on a second site, replacement roofers mid-contract: each introduction requires a fresh HMRC verification before the first payment. Managing 30 or 40 live verification records, tracking expiry and change events, and ensuring no payment is made without a current verified status is a compliance load that grows faster than headcount.

Nil returns in stop and start months

Housebuilding is inherently stop-start. A site may be paused between planning consent and groundworks start, or between first-fix completion and second-fix engagement. In any tax month where no subcontractor payments are made, a CIS300 nil return is now mandatory from 6 April 2026. The penalty for missing a nil return is £100 on day one. Many housebuilders have not yet adjusted their monthly compliance calendar to include nil-return months, because the obligation did not exist between 2015 and April 2026.

Due diligence at scale under the April 2026 anti-fraud rules

Finance Act 2026 introduced the 'knew or should have known' standard for GPS revocation and the 20%-of-payment knowledge-based penalty under FA 2004 ss.62A/62B. For a housebuilder paying 40 subcontractors, the due-diligence obligation (CIS re-verification, Companies House legitimacy check, bank account name verification before each payment) must be applied to every subcontractor, every payment cycle. One undocumented payment is not a minor omission under the new regime: it is evidence of failing the 'should have known' standard.

Deduction statement volume

A housebuilder making payments to 40 subbies in a month has 40 deduction statements to issue within 14 days of each payment. Where subbies hold GPS, no statement is required (no deduction is made). Where subbies are registered or unregistered, statements are mandatory. Managing the statement run alongside the CIS300 filing deadline in the same fortnight is a compression problem that manual processes handle poorly.

How we help

What we do for housebuilders.

Full monthly CIS cycle management

We run the complete monthly contractor-side compliance cycle for your business: subcontractor verification across your pool, CIS300 preparation and filing by the 19th, nil returns in stop months, and deduction statement issuance within the 14-day window. We maintain the verification record archive and flag status changes between payment cycles.

Due-diligence documentation system

We build and operate the pre-payment due-diligence record for each subcontractor: timestamped HMRC verification result, Companies House active-entity check, and bank account name verification. The record is maintained in a format that HMRC can be shown in the event of a supply-chain fraud investigation, demonstrating that you met the 'should have known' standard under Finance Act 2026.

GPS management and protection

If your business holds GPS, we manage the annual three-test compliance review (business, turnover, compliance) and ensure the due-diligence records that protect GPS from immediate revocation under the April 2026 rules are in place and current. We model the cash-flow cost of GPS loss so you understand what is at stake and why the documentation matters.

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“Running three sites with 35 to 40 subbies, the paperwork was a mess. The April 2026 rules made us take it seriously. Having the verification records, Companies House checks and nil returns all handled as a managed service has removed a significant source of director anxiety.”

Director, regional housebuilder, North West

Composite snapshot based on client patterns. Name and figures anonymised. The tax mechanics are real.

Questions from housebuilders

We have a site that is paused for three months. Do we need to do anything with CIS in those months?

Yes. From 6 April 2026, a nil return is mandatory for every tax month in which you make no subcontractor payments. You can either file a CIS300 nil return by the 19th of the following month or pre-notify HMRC that you will be inactive for a defined period. A pre-notification covers the quiet period without requiring a monthly return for each individual month. We manage whichever route suits your project schedule.

We use a mix of sole traders and limited companies as subbies. Does the due-diligence process differ?

Yes. For a sole trader, you verify their name and UTR with HMRC. For a limited company, the Companies House check is particularly important: you are confirming the company is active, its registration matches what you have been told and the bank account name matches the registered company name. The bank account name verification step is critical for limited companies because supply-chain fraud often involves misdirected payments to look-alike entities. Both checks need to be documented per payment cycle under the April 2026 rules.

How quickly do we need to issue deduction statements after paying a subcontractor?

Within 14 days of each payment where a CIS deduction has been made. There is no grace period. The statement must show the gross payment amount, the materials cost excluded from the deduction base, the amount liable to deduction and the net payment made. If a subcontractor holds GPS, no deduction is made and no statement is required. Where you are paying 30 or 40 subbies a month, the statement run needs to be built into the payment process rather than treated as a separate administrative task.

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Talk to a specialist housebuilders accountant

Book a free call. We will talk through your CIS position, your deduction history and whether there is anything worth changing. No hard sell, no obligation.

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Specialist in CIS and construction accounting, not a generalist practice

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24-hour response guarantee

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Fixed fees, quoted before we start

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Other trades we work with

Plumbers Electricians Joiners and Carpenters Groundworkers Roofers

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