New Build Mortgages Explained: Requirements, Deposits and Timelines

Buying a newly built home can come with plenty of exciting choices, from selecting your preferred finishes to making the space your own. But when it comes to getting a mortgage for a new-build, there are a few additional considerations to keep in mind.

Lender criteria, deposit requirements and construction timelines can all affect your mortgage options, and so it’s important to know what to expect when planning your new home purchase.

In this article, we explain the lender requirements for new build mortgages, explore the deposit options available and take you through the mortgage process step by step. Let’s begin.

What Is a New Build Mortgage?

The mortgage application process is broadly the same as buying an existing property. However, lenders may have additional considerations for new-build homes, including:

• Deposit requirements: Lenders may require larger deposits for new-build properties, particularly flats.
• Property eligibility: Lenders may have specific criteria for construction methods, developments and structural warranties.
• Mortgage offer validity: Lenders may offer longer mortgage offer periods or extensions to account for construction delays.

One of the main differences between securing a mortgage on a new-build property and an existing home is that lenders can be more cautious with their valuations.

This is because new-build homes often carry a price premium that may diminish once the property is no longer considered new. As a result, lenders may account for the possibility of a fall in value during the underwriting process when deciding how much they are willing to lend.

Although some lenders have stricter requirements for new-build properties, others offer mortgage products with features tailored to these purchases, such as preferential rates for energy-efficient homes.

How Much Deposit Do You Need for a New Build?

The mortgage deposit you need will depend on the property’s purchase price and the maximum loan-to-value (LTV) ratio your lender is willing to offer.

While some lenders offer a 5% deposit mortgage on new build properties, others may require a minimum deposit of 10% or more.

According to the latest data from the UK House Price Index (May 2026), the average new-build property in England costs £398,000. Based on this figure, here’s how much you would need to save for a deposit at different LTV ratios:

It’s important to note that while meeting the minimum deposit requirement may make you eligible for a mortgage, a larger deposit could give you access to a wider range of new build mortgage deals with more competitive interest rates.

What Are the Mortgage Requirements for a New Build Property?

When applying for any mortgage, lenders will need to assess both your ability to repay the loan and whether the property you are planning to purchase is suitable security for the mortgage.

For example, As with a standard mortgage application, lenders will consider:

• Income and affordability: Your earnings, regular expenses and existing financial commitments to assess whether you can afford the mortgage repayments.
• Credit history: How you’ve managed borrowing and repayments in the past, including any missed payments, defaults or other credit issues.
• Deposit: Whether you have sufficient funds to meet the lender’s minimum deposit and loan-to-value requirements.

For new-build homes, lenders may have additional requirements relating to the property’s construction, valuation and development. These may include:

• Property valuation: The lender’s property valuation may take into account the new-build premium, which could affect how much they are willing to lend.
• Structural warranty: Most lenders require a recognised 10-year new-build warranty, such as NHBC Buildmark. However, some lenders may accept alternative certification.
• Construction methods: Properties built using non-standard materials or modern methods of construction may need additional checks to ensure they meet the lender’s criteria.
• Development restrictions: Some lenders limit their exposure to individual developments, particularly blocks of new-build flats, which can affect mortgage availability.

What Mortgage Incentives Do Developers Offer?

To make their properties more appealing and affordable, developers commonly offer incentives that can make buying a new-build easier.

These benefits can be particularly useful if you’re a first-time buyer or simply struggling to save for a deposit and cover the upfront costs of moving.

The incentives available can vary depending on the developer, property and development. However, some of the most common include:

• Deposit contributions: The developer may contribute a set figure or percentage towards your deposit, helping reduce the total amount you need to provide from your own savings.
• Stamp Duty contributions: The developer pays some or all of your Stamp Duty Land Tax (SDLT), helping reduce your upfront purchasing costs.
• Cashback: The developer provides a straightforward cash incentive. This is usually paid on completion and can help towards moving expenses or other costs.
• Property improvements: Developers may include flooring, kitchen appliances or other fixtures and fittings at no additional cost.

How Do Developer Contributions Affect Your Mortgage?

First and foremost, developer incentives must be disclosed to your mortgage lender, as they can influence the property’s valuation and the amount the lender is willing to offer.

Many lenders accept certain developer incentives worth up to 5% of the property’s purchase price, although limits and the types of incentives accepted can vary. As such, some lenders may deduct incentives exceeding their permitted allowance from the property’s value when calculating the loan-to-value (LTV) ratio.

What this looks like in practice:

• If you’re buying a £300,000 new-build property and the developer offers a 5% deposit contribution, that’s £15,000 towards your deposit.

However, a developer contribution won’t necessarily replace your own deposit. Many lenders still require buyers to contribute some of their own savings, although the amount required will depend on the lender’s criteria.

It’s very important to distinguish between different incentives. Cash contributions, Stamp Duty payments and non-financial extras can all be assessed differently. As a result, the total value and type of incentives offered may affect your mortgage options.

Working with a trusted mortgage broker can help you understand how different lenders assess developer incentives. They can also compare suitable lenders to help you make the most of the incentives available.

Which Lenders Offer Mortgages for New Builds?

Some of the main UK lenders currently offering mortgages for new-build properties include:

• Nationwide Building Society: Offers up to 95% LTV on eligible new-build houses and 85% on flats, with mortgage offers valid for nine months.
• Halifax: Offers up to 95% LTV on eligible new-build houses and 85% on flats, with potential green mortgage incentives for energy-efficient properties.
• Skipton Building Society: Offers up to 95% LTV on eligible new-build properties, with its Track Record Mortgage potentially allowing qualifying buyers to borrow up to 100% LTV on eligible new-build houses.
• Principality Building Society: Offers up to 95% LTV on eligible new-build houses for first-time buyers and 90% on flats, with an eight-month mortgage offer and a possible eight-month extension.
• Accord Mortgages: Offers new-build mortgage products with options for eligible houses and flats.

Please note that this isn’t a complete list of lenders, and the mortgage products available will depend on your finances and the property you plan to purchase.

Working with a whole-of-market mortgage broker can give you access to a wider range of mortgage options, helping you find a suitable mortgage deal that matches your circumstances.

For example, here at Boon Brokers, we have access to over 90 lenders. Our expert advisers can compare mortgage options across the market, considering interest rates, fees and lending criteria to help you make an informed decision about selecting your mortgage.

Can You Port Your Existing Mortgage to a New Build?

Mortgage porting can be a great option for existing homeowners who want to minimise change by keeping their current mortgage deal and interest rate while avoiding an early repayment charge (ERC).

However, porting a mortgage is not an option for every borrower. Porting a mortgage generally requires a new mortgage application, as your lender will need to reassess your affordability and confirm that the new-build property meets its lending criteria.

When buying a new-build property, construction timelines can also complicate the porting process. For example, if you sell your home with an outstanding mortgage before the new-build property is ready, you will normally need to repay your existing mortgage when the sale completes. However, this doesn’t necessarily mean you will lose the opportunity to port your mortgage deal.

Some lenders may allow you to transfer your existing deal to a new property within a specified period after the original mortgage has been repaid. The conditions for this will depend on the lender’s terms, but you may be able to reclaim any early repayment charge (ERC) paid when selling your previous home.

Before making a final decision, it’s important to compare the total cost of porting your existing mortgage against taking out a new mortgage deal, particularly if you need to borrow more or want to avoid an early repayment charge.

How Long Does It Take to Get a Mortgage on a New Build?

There are several advantages when it comes to the home-buying timeline when purchasing a new-build property, some of which can help speed up the mortgage and purchasing process compared with buying an existing home. These advantages include:

No Property Chain Delays

When buying directly from a developer, there is usually no onward chain involving the seller. This can help reduce delays caused by other property transactions.

Conveyancing in Advance

Developers often prepare legal information covering the wider development, including planning permissions, building regulations and property titles.

While your solicitor will still need to review the documents and complete the necessary legal work, this can give them a head start and help them carry out their checks more efficiently.

Potentially Quicker Valuations

Many lenders may be familiar with particular developers or new-build sites, especially where they have previously arranged mortgages for properties on the same development.

This can help speed up the valuation process, as the lender may already have information about comparable properties, construction methods and the development itself. In some cases, they may be able to use an online valuation (desktop valuation) rather than arranging a physical inspection.

However, an online valuation is not guaranteed. Most importantly, the lender will still need to assess the property’s value and confirm that it provides suitable security for the mortgage.

Why Can New-Build Purchases Take Longer?

While obtaining a mortgage offer can often be streamlined for new build properties, it is worth noting that the time it takes to move into your new home will largely depend on whether you’re buying a completed new-build property or purchasing off-plan:

• Completed new build: If the property is already finished, you may be able to exchange contracts and complete your purchase relatively quickly, provided your mortgage and legal work are ready.
• Off-plan: If the property is still under construction, you could be waiting several months before moving in, depending on the stage of construction and any potential delays.

This is particularly important when arranging your mortgage, as your mortgage offer must remain valid until the purchase completes. If the property isn’t ready before your offer expires, you may need to request an extension or arrange a new mortgage offer.

What if Your Mortgage Offer Expires Before Your New Build Is Ready?

Once a mortgage offer expires, it becomes invalid, meaning you cannot complete your purchase using the original offer.

If your mortgage offer expires before completion on a new build, or is approaching its expiry date, there are generally two options to explore:

• Request an extension: Some lenders may grant an extension on the mortgage offer. However, you may need to provide updated financial documents or complete a new affordability check.
• Apply for a new mortgage: If an extension is no longer an option, then you will need to secure a new mortgage offer.

If construction delays put your mortgage offer at risk of expiring, it’s important to contact your mortgage broker or lender as soon as possible. They can help explain your options and arrange an extension or new application where necessary.

How Can a Mortgage Broker Help With Buying a New Build?

Buying a new-build property can involve coordinating several different parties, from the developer and your solicitor to your mortgage lender.

Trying to juggle construction schedules,  mortgage offers and expiry dates can be quite overwhelming, especially if you’re new to the world of mortgages. This is where having an experienced broker help can make a real difference.

At Boon Brokers, our expert mortgage advisers can compare thousands of mortgage products from over 90+ UK lenders. We can check different interest rates, fees, affordability requirements and any developer incentives that could help you find a suitable mortgage deal for your new home.

We provide you with a dedicated mortgage expert for free. They will guide you through the new build mortgage process, from identifying suitable lenders and arranging your mortgage application to communicating with the lender and supporting you through to completion. If construction delays affect your mortgage offer, we can also help you explore your options.

Our expert mortgage advice is completely fee-free, meaning you’ll pay £0 in broker fees for our advice or for arranging your mortgage.