Record Keeping for Self-Employed Builders: What HMRC Expects

‍‌‌‌‌‌‌​‌​‌​‌‌‌​‌​‌‌‌‌‌​​‌‌‌​‍SiteKiln gives you plain-English information, not legal advice. If you need advice specific to your situation, talk to a qualified accountant or tax adviser.

The short version

If you're self-employed (or filing Self Assessment), HMRC expect you to keep enough records to back up every figure on your return, and to keep them for at least 5 years after the 31 January deadline for that tax year. That includes income, expenses, CIS statements, bank statements and any other documents you'd need to prove you've filed a "correct and complete" return under TMA 1970 section 12B.

Why it matters

If HMRC open an enquiry and you can't back your numbers up, they're allowed to estimate, shift the burden of proof onto you, and could fine you for failing to keep proper records. Good records make Self Assessment easier, make HMRC checks shorter, and stop you overpaying tax because you've forgotten half your costs.

Section 12B of the Taxes Management Act 1970 says anyone who might be required to submit a return must:

• Keep all such records as may be requisite to make and deliver a correct and complete return; and
• Preserve those records until at least the end of the "relevant day" -- in practice, the retention period HMRC set out in their guidance.

HMRC's published guidance for the self-employed joins this up by telling you what records they expect, and the standard 5-year retention rule.

5.15.1 What records HMRC expect you to keep

If you're self-employed as a builder/tradie, HMRC's overview and record-keeping guides say you should keep at least:

Income records

• Invoices and sales receipts.
• Bank statements (all accounts used for the business).
• CIS payment and deduction statements.
• Any other evidence of money coming in (for example, remittance advices).

Expense records

• Purchase invoices and receipts (materials, fuel, tools, kit, insurance, phone, etc.).
• Mileage logs if you claim mileage.
• Contracts, hire agreements and finance documents for vehicles and plant.

Other supporting documents

• Copies of tax returns and computations.
• VAT records if registered (VAT returns, workings, sales/purchase listings).
• Payroll/pension records if you have staff.

Section 12B specifically mentions keeping records of "all amounts received and expended in the course of the trade" and supporting documents, and HMRC manuals echo that.

Digital is fine: scanned copies, photos, software records and PDFs all count, as long as they're readable and complete.

5.15.2 How long you must keep records

For self-employed Self Assessment:

• HMRC say you must keep your business records for at least 5 years after the 31 January submission deadline of the relevant tax year.

Example:

• 2024/25 tax year, online filing deadline 31 January 2026.
• You must keep records for that year until at least 31 January 2031.

If you send a very late return (more than 4 years after the deadline), HMRC say you must keep the records for at least 15 months after you send the return.

For other situations:

• Employees who only have PAYE generally need to keep pay and tax records for 22 months after the end of the tax year.
• Limited companies often need to keep records for 6 years (Companies Act plus tax rules), sometimes longer if there are investigations or special circumstances.
• If there's an ongoing HMRC enquiry, you should keep records until it's formally closed, even if that's beyond the normal 5 years.

5.15.3 What "good enough" looks like in practice

HMRC's own guides and tax-adviser commentary boil "good record keeping" down to:

• Complete -- every sale and purchase is captured somewhere (software, spreadsheets, bank + CIS statements).
• Consistent -- figures on your tax return can be traced back to underlying records without gaps.
• Readable and accessible -- HMRC must be able to understand a record if they ask to see it; a faded or unreadable photo may not cut it.
• Backed by bank statements -- these are often the backbone; they should match your sales and expense records.

HMRC manuals note that if you fail to keep records under section 12B, they can still accept other evidence, but you're starting from a weaker position if they're reconstructing from scraps.

5.15.4 What happens if you don't keep proper records

If you don't keep or preserve records as required:

• HMRC can penalise you separately for failing record-keeping obligations (up to £3,000 per tax year in some situations).
• In an enquiry, they may estimate your income/expenses less generously if you can't produce documents, and it becomes harder to challenge their view.
• Poor records also increase the risk of errors, which can then attract penalties on top under the normal error penalty regime.

For a small builder, the real cost is often that you can't prove legitimate expenses or CIS deductions, so you overpay tax and lose out on refunds.

Minimum kit -- records a one-man builder should keep

If you do nothing else, keep these and you'll be miles ahead of most:

Bank statements (business account if you have one):

• Download a PDF for every month and save it -- this is your spine if HMRC ever ask questions.

CIS payment and deduction statements:

• One for every pay from each contractor.
• Keep them in date order -- these prove both income and CIS tax already paid.

Sales invoices / job sheets:

• A simple invoice for each job or week, even if it's just labour.
• Number them and match them to payments in your bank.

Receipts for expenses:

• Fuel, merchants, tool shops, insurance, phone -- keep either the paper or a clear photo in an app or a folder.
• For mileage claims, keep a basic log (date, from/to, miles, job).

Big-ticket documents:

• Finance or HP agreements for vans and kit.
• Insurance policies and renewal docs.

Tax copies:

• PDF of each Self Assessment return and HMRC's tax calculation for that year.

If you can throw all of that into one organised digital folder per tax year (or into decent bookkeeping software), you're at the level HMRC describe as "good record keeping" -- and you'll find your own tax returns a lot less painful.

What to do next

• Set up one digital folder per tax year and save bank statements, CIS statements, invoices and receipts in it.
• Download bank statements as PDFs every month -- this is your backbone if HMRC ever ask questions.
• Keep CIS payment and deduction statements in date order so they match your tax return.
• Keep everything for at least 5 years after the 31 January submission deadline for that tax year.

Sources and legislation

• Taxes Management Act 1970 -- section 12B: duty to keep and preserve records for correct and complete returns. legislation.gov.uk/ukpga/1970/9
• Finance Act 2004 -- CIS record-keeping and reporting obligations. legislation.gov.uk/ukpga/2004/12
• Income Tax (Trading and Other Income) Act 2005 -- trading income records and allowable deductions. legislation.gov.uk/ukpga/2005/5

Related guides on this site

• 5.3 Filing Self Assessment -- construction-specific deductions
• 5.6 Expenses you can claim
• 5.7 HMRC investigation
• 5.8 Making Tax Digital
• 5.14 Self Assessment penalties
• S9 Setting up as a sole trader -- step by step

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