Assessed on your gross earnings — not your take-home after the CIS deduction. Specialist mortgage advice for Construction Industry Scheme workers.
Under the Construction Industry Scheme, contractors have 20% tax deducted at source by the main contractor before payment. What lands in your bank account is 80% of what you earned. This causes a specific problem with mainstream lenders: they see your bank statements, observe the net figures, and assess your income on those numbers.
A CIS contractor earning £800/week gross receives £640/week net. Over a year that’s £41,600 gross vs £33,280 net. At a 4.5× income multiple, the difference is £37,440 in borrowing power — a meaningful gap when you’re trying to buy a home.
Specialist CIS mortgage lenders understand the scheme. They assess income on gross CIS earnings as evidenced by CIS deduction statements — the formal records issued by main contractors showing gross payment and deduction. This gives an accurate picture of what you actually earn.
Your main contractor(s) issue monthly or weekly CIS deduction statements showing gross payment and the 20% deduction. These are the primary income evidence for a CIS mortgage.
Most lenders want 12 months of CIS statements to calculate average weekly or monthly gross earnings. Some accept 3 months. Gaps are noted and explained.
Total gross CIS earnings are annualised and an income multiple of 4–4.5× applied. Bank statements confirm the payment trail.
Figures are illustrative. Actual borrowing depends on lender criteria, deposit, credit profile, and individual circumstances.
The critical distinction. Using gross CIS earnings rather than net pay is what separates a specialist CIS lender from a standard one. Make sure your broker understands this before submitting any application.
If you work for multiple main contractors, income from all of them can typically be combined, provided all are evidenced with CIS statements.
CIS contractors submit self-assessment tax returns annually. SA302 forms and a tax year overview from HMRC are often requested alongside CIS statements, particularly for larger loans.
Some experienced CIS contractors hold gross payment status (no deduction at source). If this applies to you, income is evidenced through bank statements and self-assessment rather than deduction statements.
Yes. Specialist lenders assess CIS contractors on their gross earnings as shown on CIS deduction statements — not on net pay after the 20% CIS tax deduction. This produces a significantly higher and more accurate affordability figure.
Typically 12 months of CIS deduction statements from your contractor(s), 3–6 months of bank statements, and SA302 self-assessment forms or a tax overview from HMRC. Some lenders accept 3 months of CIS statements.
Specialist CIS mortgage lenders use gross earnings before the CIS deduction. Standard lenders may only use net pay, which significantly reduces the mortgage offer. Using the right lender is the critical difference.
Some lenders require 12 months of CIS history. Others are more flexible. If you have fewer than 12 months, it’s worth a conversation before assuming you can’t proceed.
Yes, slightly. If you operate through a limited company registered under CIS, income evidencing follows a different path — company accounts and HMRC records rather than individual deduction statements. Specialist advice is particularly important in this scenario.
We understand how CIS income works. No obligation — just a straight conversation about what you can borrow.
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CII CF1 · CF6 · ER1 — Contractor mortgage specialist
30 years inside UK mortgage lending. Chris has helped CIS contractors and construction workers secure mortgages assessed on gross earnings, not take-home.
Page reviewed July 2026.