A strong CIS income can put you in a better position than a standard high street affordability calculation suggests. Yet many subcontractors are still told they need a large deposit, years of accounts or a permanent contract before they can buy. The reality is more practical. CIS mortgage deposit options can start from 5% of the property price, provided the lender understands how you are paid and your wider application is packaged correctly.
Your deposit matters, but it is only one part of the decision. A lender will also look at your CIS income, work history, credit profile, monthly commitments and the property itself. Getting the right combination is what helps you move forward without changing your tax position or forcing your income into a salaried mould.
How much deposit do CIS workers need for a mortgage?
For many CIS workers, a 5% deposit is possible. On a £300,000 property, that means £15,000, with a mortgage of £285,000. However, the number of lenders available and the interest rates offered tend to improve as your deposit rises.
A 10% deposit is often a useful turning point. It can open more product choices and may make an application easier where there are minor credit issues, variable hours or a shorter contracting history. At 15% or 20%, rates can become more competitive again because the lender is taking on less risk relative to the property value.
That does not mean you should delay buying solely to reach the next deposit band. If the right property is available now, your income supports the borrowing and the monthly payment remains comfortable, a 5% or 10% deposit can be the sensible route. The right choice depends on the cost of waiting, likely property price movement and whether keeping some cash back for legal fees, moving costs and an emergency fund is more valuable than putting every pound into the deposit.
CIS mortgage deposit options that lenders can accept
The source of your deposit needs to be clear, traceable and acceptable to the lender. This is where applications can slow down unnecessarily if paperwork is left until the last minute.
Savings built from CIS earnings
Savings from your own income are usually the most straightforward option. Lenders will normally want bank statements showing the money accumulating and evidence of where any larger credits came from. CIS payslips, bank statements and contracts can help demonstrate that the deposit has been built from legitimate earnings.
If your money is spread across several accounts, that is not automatically a problem. The key is being able to show the full trail. Avoid moving funds around repeatedly shortly before applying, as this can make a simple source-of-funds check look more complicated than it needs to be.
A gifted deposit from family
A gifted deposit is common, particularly for first-time buyers. Most lenders accept gifts from close family members, although their definitions vary. The person providing the money will usually need to sign a declaration confirming it is a genuine gift, not a loan that must be repaid, and that they will have no ownership interest in the property.
They may also need to provide identification, proof of address and bank statements showing where the funds came from. Be upfront if the gift comes from abroad, from a business account or follows the sale of an asset. These can all be workable, but they can require extra checks.
A loan from family is different. If you need to repay it monthly, a lender may treat that repayment as a commitment and reduce the amount you can borrow. Never describe a repayable arrangement as a gift. Full disclosure protects the application and prevents problems with the solicitor later.
Equity from an existing property
If you already own a home, the equity in it can form the deposit for your next purchase. This might come from the sale proceeds, or from a remortgage where you are raising capital for a buy-to-let or another property purchase.
The important calculation is not just how much equity you have on paper. You need to account for your current mortgage balance, estate agency and legal costs, any early repayment charge, and the affordability of the new borrowing. A larger deposit is useful only if the overall plan remains affordable and sustainable.
Lifetime ISA and other government-backed savings
A Lifetime ISA can be used towards a first home if the scheme rules are met. This may be particularly valuable where you have saved consistently but need help reaching a 10% deposit. The provider and solicitor will manage the withdrawal process, so timings matter.
Help to Buy equity loans are closed to new applications in England, Scotland and Wales, but buyers who already own through the scheme may have specific remortgage or repayment considerations. Specialist advice is worthwhile before changing lender or borrowing more against the property.
Deposit from a property sale, inheritance or investment
Sale proceeds, inheritance and funds released from investments can all be acceptable sources. Expect more documentation where the money has recently arrived or has passed through several accounts. Keep completion statements, probate documents, investment statements and bank records available from the outset.
Why the deposit is not the whole CIS mortgage picture
A bigger deposit does not automatically solve an affordability problem. Some mainstream lenders assess CIS applicants using net income after deductions, or ask for accounts that do not reflect the way an established subcontractor actually works. This can limit borrowing even when your day rate, contract pipeline and gross CIS earnings are strong.
Specialist contractor lenders may assess your income using CIS payslips and bank statements, often taking a more realistic view of gross earnings before tax deductions. Their exact criteria differ. Some want a minimum period working under CIS, while others focus on continuity in the same trade and the strength of the current contract.
This is why a 10% deposit with the right lender can be more powerful than a 20% deposit sent to a lender that does not understand CIS income. Deposit size affects loan-to-value and pricing. Income assessment determines whether you can borrow enough to buy the property you want.
Choosing between a 5%, 10% and 15% deposit
The cheapest rate is not always the cheapest overall mortgage. A lower-deposit product may have a higher interest rate, but it could allow you to buy sooner and keep a healthy cash reserve. A larger deposit may reduce your rate, but not if it leaves you short when the boiler fails, work slows temporarily or you face a gap between contracts.
Look at the full monthly payment, fees, product term and any early repayment charges, not just the headline rate. If you expect to remortgage within two years after building more equity, a product with a large fee may not be the best value. If you want certainty while working on a long-term project, a longer fixed rate may suit you better.
New-build properties can have their own deposit rules. Some lenders require a higher deposit for new-build flats than houses, and developer incentives must be declared. Shared ownership can also be an option, but affordability includes the mortgage payment, rent on the unsold share and service charges. It can reduce the upfront purchase price, although it is not right for every buyer.
Preparing your deposit before you apply
A well-prepared deposit can help keep a time-sensitive purchase moving. Before an Agreement in Principle, gather recent bank statements for every account holding deposit money, your CIS payslips, proof of your current and previous contracts, and evidence for any gifted or inherited funds.
Avoid taking out new credit, missing payments or using an undisclosed personal loan to top up the deposit. Lenders and solicitors carry out checks for good reason, and last-minute surprises can delay or derail an offer. If your deposit has an unusual element, explain it early so the lender can be chosen around the facts rather than around assumptions.
At Residential Mortgage Hub, we match CIS applicants with lenders that assess contractor income properly, then package the deposit and income evidence clearly from the start. That can mean more suitable borrowing options, fewer avoidable questions and a faster route from offer to mortgage approval.
The best deposit is not simply the largest amount you can gather. It is the amount that gives you access to the right lender, keeps your monthly costs comfortable and still leaves you financially secure once you have the keys.
