New Build Mortgages for Couples with Unequal Deposits

Turn Unequal Deposits Into a Strong New-Build Offer

Buying a new-build home as a couple is exciting, but it can get awkward fast when one of you has a much bigger deposit. Maybe one partner has been saving for years, or has money from selling a previous home, while the other is starting from scratch. You both want the same front door, but you are not bringing the same cash to the table.

This matters even more when you are getting a mortgage for a new-build property. Prices can be higher, reservation deadlines can be tight, and lenders often have stricter rules for new-builds. In this guide, we will walk through how unequal deposits affect your mortgage options, how to protect each partner’s contribution, and how to put forward a strong new-build offer as a couple without losing time or sleep.

‍Understanding New-Build Mortgages for Modern Couples

First, it helps to be clear on what lenders mean by a new-build. In simple terms, a new-build is a property that has been newly constructed and has not been lived in before. Some lenders also treat homes that are newly converted, such as an office turned into flats, in a similar way.

Mortgages for new-build homes are often treated differently because of things like:

• Builder incentives such as cashback, paying your legal fees, or including extras  

• Concerns about valuation if the market cools before you complete  

• Possible delays between reserving, exchanging, and actually moving in  

In busy periods, build schedules can be tight, exchanges are pushed quickly, and developers may encourage you to use their preferred broker or lender. That can feel easier in the moment, but it may not suit your situation, especially with uneven deposits or more complex income.

Unequal deposits also sit right at the heart of:

• Affordability checks on both your incomes  

• Loan-to-value (LTV) bands that drive your interest rate  

• How gifted deposits or schemes like shared ownership are treated  

If one partner is putting in much more money, that bigger chunk can help you hit a better LTV band on a mortgage for a new-build property, but it can also raise fair questions about who owns what.

‍How Different Deposit Sizes Affect What You Can Borrow‍

LTV is simply the percentage of the property price you are borrowing. If you buy at £300,000 and put down £60,000, you are borrowing £240,000, which is 80 per cent LTV. The lower your LTV, the less risk the lender is taking, so the pricing of the deal often improves.

With a couple:

• Both incomes are usually used to check affordability  

• The total deposit from both of you sets the LTV  

• The person with the larger deposit often tips you into better rate territory  

So one partner’s bigger deposit can:

• Help you move from a 90 per cent LTV band down to 85 or 80 per cent  

• Open up lender options that are stricter for higher LTV new-build deals  

• Reduce the impact of some new-build restrictions, such as lower maximum LTVs  

New-build properties often have their own quirks. Some lenders ask for a higher minimum deposit for new-build flats than for older houses. There can be retention policies, where the lender holds back part of the funds if they have concerns about value or finish. Incentives from the developer can also affect what is counted as your real deposit, because some lenders will treat incentives as part of the price rather than extra cash.

This is where careful structuring matters. The headline number you pay is not the only figure that matters to the lender. The mix of incentives, your cash, and any gifted funds all feed into the LTV on a mortgage for a new-build property, and the bigger depositor will often be the one shifting that dial.

‍Protecting Unequal Contributions Without Slowing Your Purchase

When one partner is putting in more money, it is natural to want that reflected in the ownership. There are two main ways couples usually own property together:

• Joint tenants, where you each own the whole property together  

• Tenants in common, where you each own a set share  

For couples with unequal deposits, tenants in common usually makes more sense. You can agree that one partner owns a larger share, or that your shares will adjust as the mortgage is paid off. This does not have to be complicated, but it does need to be set up properly.

A Deed of Trust, also called a Declaration of Trust, is often the key document. It can record:

• How much each of you is putting in at the start  

• How the sale proceeds will be split if you sell or separate  

• What happens if one person pays more of the mortgage later  

To keep things smooth:

• Instruct a solicitor early, as soon as you reserve the plot  

• Tell them about the deposit split and that you want a Deed of Trust  

• Make sure the legal work lines up with exchange and completion dates from the developer  

It is also worth thinking about protection. Life cover and other policies should reflect your real stakes. If one partner is putting in far more, you will both want to know the mortgage can still be covered if something serious happens.

‍Choosing the Right New-Build Mortgage as a Couple

Once you are clear on ownership and deposits, you can focus on the actual mortgage for a new-build property. Different products can work well for couples with uneven deposits, for example:

• Fixed rates to give stable payments while you settle into the new home  

• Higher LTV products if one partner has a smaller deposit but you still want to move soon  

• Specialist new-build deals from lenders who are more comfortable with new developments  

Whole-of-market advice becomes especially helpful when:

• One of you is self-employed or has variable income  

• There is any past credit blip that might worry a mainstream lender  

• Family are helping with part of the deposit or gifting funds  

• You are using schemes like shared ownership or First Homes  

An independent broker with access across the market can help you:

• Match the lender to your income patterns and deposit split  

• Work within new-build timescales, from reservation to completion  

• Structure the mortgage so both partners’ long-term goals are supported  

At Prosper Home Loans, based in Sussex and working with clients across the UK, we regularly help couples balance unequal deposits with the right ownership and mortgage setup for new-builds and more complex lending.

‍Secure Your New-Build Future Together This Summer

If you are hoping to move into a new-build home later in the year or next, early planning makes everything calmer. Before you reserve a plot, it helps to:

• Get an Agreement in Principle so you know your borrowing power  

• Check your credit files and tidy up anything obvious  

• Talk openly as a couple about budgets, deposits, and long-term plans  

Unequal deposits do not have to be a problem. With clear legal protection, a thought through ownership structure, and a carefully chosen mortgage for a new-build property, you can both feel confident that the move is fair as well as affordable. Working with a whole-of-market broker like Prosper Home Loans can give you space to focus on the fun parts of choosing your new home, while the technical details are handled in the background.

‍Secure Expert Support For Your New-Build Purchase Today

If you are considering a mortgage for a new-build property, we can guide you through each step so you know exactly what to expect. At Prosper Home Loans, we take the time to understand your plans and match you with options that fit your budget and timescales. Speak to our advisers to get clear, straightforward answers to your questions and a tailored recommendation. To book a no-obligation chat, simply contact us.