Self-Build Mortgages and Stage Payments

This guide explains how self-build mortgages work, how lenders release funds during construction, what deposit you are likely to need and what has changed following the closure of the Help to Build Equity Loan scheme. Whether you are planning to build on a plot you already own or purchasing land and constructing from scratch, understanding the mechanics of stage payments and lender criteria will help you plan the project and its financing together.

Your home may be repossessed if you do not keep up repayments on a mortgage or any other debt secured on it.

For a free initial consultation about self-build mortgage options, call 01202 155992 or contact Mortgage One.

What Is a Self-Build Mortgage

A self-build mortgage is a specialist product designed for people who are building their own home rather than buying an existing property. Unlike a standard purchase mortgage, which releases the full loan amount on completion, a self-build mortgage releases funds in stages as construction progresses. During the build phase, you typically pay interest only on the funds drawn down so far. Once the build is complete, the mortgage converts to a standard repayment basis.

Self-build mortgages are distinct from new build mortgages, which are used to purchase properties built by a developer. With a self-build mortgage, you are the one managing or commissioning the construction, and the lender needs to be satisfied that the project is viable, properly costed and adequately supervised. Mortgage One’s new build mortgages guide explains the differences between self-build and new build lending.

How Stage Payments Work

The defining feature of a self-build mortgage is the stage payment structure. Rather than receiving the full loan at the outset, the lender releases funds at agreed points during construction. The typical stages for a conventional brick and block build are land purchase, foundations, wall plate or eaves height, wind and watertight, first fix, second fix and completion. The exact stages and number of releases vary by lender and construction method.

There are two main types of stage payment:

Arrears stage payments. Funds are released after each stage is completed and inspected by a valuer or surveyor. This is the more common type. Because you need to fund each stage yourself before being reimbursed, arrears mortgages require you to have savings or access to other funds during the build. Lenders may offer more competitive rates on arrears products because the completed work provides security at each draw-down point.

Advance stage payments. Funds are released before each stage begins, giving you the cash to pay for materials and labour upfront. Advance products are less widely available and typically carry slightly higher rates, but they are essential for borrowers who do not have substantial savings to bridge the gap. They are also particularly useful for timber frame and other off-site manufactured construction methods where the structure may need to be paid for in full before delivery.

Some specialist providers offer cost-based mortgages where the stage payments are guaranteed based on your project costs rather than being subject to interim valuations. This gives greater certainty that you will receive the agreed amount at each stage, regardless of the valuer’s assessment of the property’s value at that point.

To discuss which stage payment structure suits your project, call 01202 155992 or contact Mortgage One.

Deposit and Loan-to-Value Requirements

Self-build mortgages generally require a larger deposit than standard residential mortgages. Most lenders require a minimum deposit of 25 per cent of the total land and build costs, giving a maximum loan-to-value of 75 per cent. Some specialist providers offer up to 85 per cent LTV on cost-based products, and a small number may go higher in specific circumstances.

If you already own the land, some lenders will take the land value into account as part of your equity contribution, which can reduce the cash deposit required. The land must usually be unencumbered or, if there is an existing mortgage on it, the self-build lender must be willing to take a first charge.

What Lenders Require

Self-build mortgage applications are more complex than standard purchase applications. Lenders typically require:

•       Full planning permission for the proposed build. Some lenders may consider outline planning permission, but most require detailed permission before they will issue an offer.

•       Detailed architectural plans and specifications, including drawings, a schedule of works and a realistic construction timeline.

•       A comprehensive project costing, broken down by stage, showing estimated costs for materials, labour, professional fees and contingency.

•       Evidence of how the build will be managed, whether you are using a main contractor, managing individual trades yourself or using a project manager.

•       A structural warranty or architect’s certificate arrangement. Most lenders require a 10-year structural warranty from an approved provider such as NHBC, Premier Guarantee, LABC Warranty or Protek. The warranty must be in place before the first stage payment is released.

•       Standard mortgage affordability checks, including income verification, credit assessment and existing commitments.

Construction type can affect lender choice. Conventional brick and block builds are accepted by most self-build lenders. Timber frame, structural insulated panels, oak frame, and modular or off-site manufactured construction methods are accepted by some lenders but not all. Mortgage One’s non-standard construction mortgage guide explains how construction type affects lender choice more broadly.

What Happens When the Build Is Complete

Once the build is finished and a completion certificate has been issued, the self-build mortgage typically converts from interest-only to a standard repayment mortgage for the remainder of the term. At this point, you may have the option to remortgage to a different lender if a more competitive product is available.

The completed property will usually be valued independently, and the final value may differ from the original cost estimate. If the completed value is higher than the total build cost, you will have built in equity from day one, which could improve your loan-to-value position and give you access to better rates on any subsequent remortgage.

The Help to Build Equity Loan: Now Closed

The Help to Build Equity Loan scheme, which allowed self-builders to secure a mortgage with a 5 per cent deposit supported by a government equity loan of up to 20 per cent of total costs, closed to new applications on 31 March 2025. The scheme is no longer available for new projects.

Self-builders who already hold a Help to Build equity loan should contact Homes England about repayment terms. The equity loan is interest-free for the first five years, after which interest is charged at 1.75 per cent in year six, rising annually by the Consumer Price Index plus 2 per cent.

Alternative Financing Options

If a self-build mortgage is not suitable or does not cover the full project cost, other financing routes may be available:

•       Remortgaging an existing property to release equity for the build. This can work if you have significant equity in your current home, but you will be carrying two mortgages simultaneously.

•       Bridging finance to cover short-term funding gaps, for example between purchasing the land and arranging the self-build mortgage. Mortgage One’s bridging loans guide explains how short-term secured lending works.

•       For larger or more complex projects involving multiple units, development finance may be more appropriate than a self-build mortgage. Mortgage One’s development finance guide covers the criteria and structure for this type of lending.

How Mortgage One Can Help

Self-build mortgages are offered by a relatively small number of lenders, many of which are building societies and specialist providers. As a whole of market mortgage broker, Mortgage One can search across these lenders to find products that match your project type, construction method, stage payment preference and deposit position.

This includes assessing whether an advance or arrears product is more appropriate for your cash flow, identifying lenders who accept your chosen construction method, and ensuring the structural warranty arrangements meet the lender’s requirements. Mortgage One’s mortgage application guide covers the documentation and process involved in applying for a mortgage.

Figures as of April 2026, London time.

For expert guidance on self-build mortgages, call 01202 155992 or contact Mortgage One.

The information provided in this article is for general guidance only and does not constitute personal or regulated financial advice. If you’d like to understand what these moves could mean for you, speak to Mortgage One. We can explain your options and timings based on your specific circumstances.

Some Buy to Let mortgages are not regulated by the Financial Conduct Authority.

FAQs

1. What is a self-build mortgage?

A self-build mortgage is a specialist loan that releases funds in stages as your home is built, rather than as a single lump sum. During the build phase, you typically pay interest only on the funds drawn down so far. Once the build is complete, the mortgage converts to a standard repayment basis.

2. How much deposit do I need for a self-build mortgage?

Most lenders require a minimum deposit of 25 per cent of the total land and build costs. Some specialist providers offer up to 85 per cent LTV. If you already own the land, its value may count towards your deposit.

3. What is the difference between advance and arrears stage payments?

With arrears payments, funds are released after each build stage is completed and inspected. With advance payments, funds are released before each stage begins. Arrears products are more common and may offer lower rates, but advance products are better for borrowers with limited savings.

4. Do I need planning permission before applying?

Most lenders require full planning permission before they will issue a mortgage offer. A small number may consider applications at the outline planning stage, but this can affect rates and product choice.

5. Do I need a structural warranty?

Yes. Most lenders require a 10-year structural warranty from an approved provider such as NHBC, Premier Guarantee, LABC Warranty or Protek. The warranty arrangement must usually be in place before the first stage payment is released.

6. Is the Help to Build scheme still available?

No. The Help to Build Equity Loan scheme closed to new applications on 31 March 2025. Self-builders who already hold a Help to Build equity loan should contact Homes England about repayment terms.

7. Can I build on land I already own?

Yes. If you already own the land, you can apply for a self-build mortgage to finance the construction. The land value may count towards your equity contribution, reducing the cash deposit required.

8. What happens when the build is finished?

The mortgage typically converts from interest-only to a standard repayment mortgage. The completed property will be valued, and you may have the option to remortgage to a different lender if a more competitive product is available.