If you work in construction under the Construction Industry Scheme — whether as a subcontractor, sole trader, or limited company — choosing the right mortgage assessment is crucial. The wrong lender may treat you as self-employed and base affordability on net profit, while the right lender will assess your gross earnings to reflect your true income.
Mortgage Knight works with lenders who understand CIS, assess income correctly, and offer competitive mainstream rates.
The Construction Industry Scheme (CIS) is a tax arrangement operated by HMRC that applies to contractors and subcontractors in the construction industry. Under CIS, contractors deduct tax at source — typically **20% for registered subcontractors** and 30% for unregistered — before paying subcontractors for their work.
CIS workers include: groundworkers, bricklayers, electricians, plumbers, carpenters, roofers, plasterers, scaffolders, steel fixers, civil engineers, and others working on construction projects.
You may be registered as a sole trader, a limited company, or through an umbrella arrangement. Each structure is treated differently by mortgage lenders — and each has lenders that handle it well.
Many lenders use SA302 net profit, which often understates your real income and reduces borrowing.
Some lenders use gross income from recent payslips/remittances, giving a more accurate and higher affordability.
Income is calculated using your daily/weekly rate, often producing the highest borrowing potential.
Halifax, NatWest, Nationwide, TSB, TML and others assess CIS income correctly.
Requirements vary by lender and method. Typical documentation:
3–6 months’ CIS remittance slips (showing gross income before deductions) — most commonly requested
12 months’ bank statements (some lenders use deposits to determine gross income)
SA302 and tax year overviews (where self-employed route is used)
Current contract or order confirmation (where day rate method is used)
Proof of CIS registration (some lenders request this)
We identify which evidence your specific case requires before any application is submitted.
Most commonly assessed using remittance slips or SA302. The gross income on remittance slips is the most accurate reflection of earnings. Three months' slips averaged and annualised is the standard approach with CIS-friendly lenders.
Can access both the CIS remittance slip route and, where applicable, the day rate contractor route. Lender selection is more nuanced — we assess which method produces the best outcome for your specific figures.
Treated as PAYE. Payslips from the umbrella company are used. The gross contractual rate should be reflected in payslips — if it is not, the lender will use the lower payslip figure.
Mortgage Knight is a whole-of-market FCA-authorised broker (FCA No: 994617) based in Watford, operating nationally. We place CIS contractor applications across the UK and work with lenders who assess CIS income correctly — using gross remittance slips, not just what appears on a tax return.
Broker fee: £495, payable on application.
Based on gross annualised earnings assessed by the lender, most contractor-friendly lenders offer 4.5× to 5× income.
| Gross Weekly Earnings | Annualised (×46) | At 4.5× | At 5× |
|---|---|---|---|
| £600/week | £27,600 | £124,200 | £138,000 |
| £900/week | £41,400 | £186,300 | £207,000 |
| £1,200/week | £55,200 | £248,400 | £276,000 |
| £1,500/week | £69,000 | £310,500 | £345,000 |
| £2,000/week | £92,000 | £414,000 | £460,000 |
Yes. A number of lenders including Halifax and Nationwide specifically accommodate CIS contractors, assessing income from gross remittance slips rather than net profit from accounts.
The most common method with CIS-friendly lenders is to average the most recent 3 months of gross CIS remittance slips and annualise the figure. This is significantly more favourable than a standard self-employed assessment based on net profit.
Not necessarily. Several lenders will assess CIS income using remittance slips without requiring full accounts. Requirements vary by lender and we identify the right approach for your situation.
Yes. Sole trader CIS subcontractors are assessed using remittance slips or SA302 depending on the lender. Gross remittance slip income typically produces the best borrowing figure.
Yes, with qualifying lenders. A larger deposit improves the rate and broadens lender choice.
