What a CIS mortgage really is

There’s a common misconception that a “CIS mortgage” is a special, separate product with its own rates and rules. It isn’t. A CIS mortgage is simply a standard residential mortgage where the lender assesses your income using your CIS payslips or statements, rather than putting you through the full self-employed route of two or three years’ accounts and SA302s. The reason this exists as a recognised approach is that CIS subcontractors sit in an awkward middle ground: you’re classed as self-employed, but unlike a typical sole trader, you’re paid through something that looks a lot like a payslip — regular weekly or monthly amounts with a clear gross figure and tax already deducted. That payslip-like structure opens a door: some lenders will read those gross figures directly to work out your income, which is faster and often far more generous than waiting for your accountant to file accounts that show a much lower net profit. It’s a standard mortgage — the difference is purely in how the lender reads your income, and that difference is everything for a CIS worker.

The gross-vs-net difference (worth £100k+)

How CIS works, and why it confuses lenders

The Construction Industry Scheme (CIS) is HMRC’s tax system for the construction sector. Under it, the contractor who hires you deducts a flat percentage from your pay before paying you, and sends it to HMRC as an advance against your annual tax bill. The rates are 20% for registered subcontractors and 30% for those who aren’t registered. You still complete a self-assessment tax return each year, where your actual tax is reconciled (and higher-rate taxpayers may owe more, or lower earners may be due a refund). CIS covers a broad range of construction trades — builders, electricians, plumbers, groundworkers, and even related work like landscaping, demolition and site preparation. The reason this confuses lenders is that it creates a hybrid picture: you’re self-employed, but you’re paid like an employee, with regular statements showing gross pay and tax deducted. Lenders who don’t understand CIS default to treating you as fully self-employed and demand years of accounts, assessing you on net profit. Lenders who do understand it read your CIS statements and assess your gross — which is the whole point of seeking out a CIS-friendly lender.

What you need to apply

One of the biggest advantages of the CIS route is that the documentation is often lighter than the full self-employed process. Typically, a CIS-friendly lender will ask for:

• Recent CIS payslips or statements — usually the last 3 to 6 months, sometimes up to 12, showing your gross pay and deductions. Lenders average these to work out your annual income.
• Bank statements — commonly 3 to 6 months, to verify the income landing in your account.
• Proof of CIS registration and evidence of continuous work history in the industry.
• Standard ID and proof of deposit, as with any mortgage.

Crucially, this means many CIS workers can get a mortgage with much less trading history than a standard self-employed applicant — where a sole trader might need two or three years of accounts, a CIS subcontractor can often be assessed on just a few months of payslips. That’s a genuine advantage if you’re relatively new to self-employment or haven’t built up years of accounts yet. It’s a similar principle to how a day-rate contractor can be assessed on their contract rate — the payslip-style evidence unlocks a simpler route than full self-employed underwriting.

Which lenders are CIS-friendly

Not every lender offers CIS-based assessment, and this is where it pays to know the market. Several mainstream and specialist lenders are known for reading CIS income properly — working from gross payslips rather than defaulting to net-profit accounts. The pool includes high-street names alongside specialist lenders, but their criteria vary significantly: some want three months of payslips, others six or twelve; some accept a shorter industry history than others; and their income multiples and rates differ. Because the pool of genuinely CIS-friendly lenders is smaller than the whole market, and their criteria are so varied, this is a situation where a whole-of-market broker adds real value — they know which lenders read CIS payslips the right way, which default to the self-employed route, and where the higher borrowing and cleaner approvals actually are. Applying to the wrong lender can mean a needlessly low offer or a decline; being matched to the right one can mean tens of thousands more in borrowing. We don’t recommend specific lenders here — the right one depends on your circumstances, which is exactly what a broker assesses.

Deposit, credit and borrowing

Beyond the income assessment, CIS mortgages work like any other residential mortgage. A few practical points:

• Deposit — the usual rules apply; a larger deposit opens better rates. Aiming for at least 10% is sensible, though lower-deposit options exist. See loan-to-value for how your deposit affects your rate.
• Credit history — as with any mortgage, your credit profile matters. CIS workers with adverse credit can still get mortgages, but the pool of willing lenders narrows further, making specialist broker knowledge even more valuable.
• Borrowing amount — most CIS-friendly lenders offer around 4 to 5.5 times your gross income, so on £50,000 gross you might borrow up to roughly £275,000, subject to your wider profile.
• First-time buyers and remortgages — the CIS approach works whether you’re buying your first home or remortgaging; the income assessment is the same principle.

CIS mortgages: FAQs

Last updated: August 2026. CIS rules and lender criteria verified at the time of writing and subject to change.