1. Does the plot have suitable planning permission?
Most self-build lenders need detailed or full planning permission before releasing funds for the build. Outline permission alone is rarely enough. Check what the permission allows, any conditions attached and when it expires.
Look at access, services and ground conditions too. Connecting water, power and drainage can be costly on rural plots. A soil or ground survey may reveal foundation issues. Trees, rights of way, covenants and flood risk can also limit what you can build. Your solicitor should review the title carefully. Some buyers agree a purchase subject to planning, which reduces the risk of owning land they cannot build on.
2. How do self-build mortgages release money?
Self-build mortgages release money in stages as the build progresses, rather than as one lump sum. Typical stages include land purchase, foundations, wall plate, watertight and completion. The lender usually sends a surveyor to check each stage before paying.
- Arrears stage payments: funds are released after each stage is finished. You need cash to pay for the work first.
- Advance stage payments: funds are released before each stage starts. This can ease cash flow but is offered by fewer lenders.
Lenders often fund up to around 75% of land and build costs, but criteria vary widely. Each stage inspection needs to happen before money moves, so build a few days into your schedule for surveyor visits. Delays at one stage can hold up payments for the next. Our self-build mortgages page explains the options.
3. Are my build costs realistic?
Lenders want detailed costings, ideally from a quantity surveyor, architect or main contractor. Vague estimates can lead to a lower loan or a decline. Underestimating costs is one of the most common reasons self-builds run short of money.
Include professional fees, building control, utility connections, landscaping and fit-out, not just the shell. Get several contractor quotes and check what is excluded. Material and labour prices can change during a build, so review your figures before you commit.
Decide how you will manage the build. Using a main contractor on a fixed-price contract gives more cost certainty but usually costs more. Managing trades yourself can save money but takes time and experience. Lenders may ask about your approach and who is supervising the work.
4. How much contingency should I keep?
Keep a contingency fund for overruns, delays and surprises. Many self-builders aim for 10% to 15% of build costs or more, depending on the complexity. Lenders may ask how you will cover cost increases.
Also plan where you will live during the build. Rent or an existing mortgage adds to monthly outgoings. Interest on the self-build mortgage is usually charged only on the amount released so far, so payments rise as more money is drawn.
Some self-builders reclaim VAT on eligible new-build costs through the HMRC scheme for DIY housebuilders. The rules are specific, so take advice early and keep every invoice. A reclaim usually arrives after completion, so do not rely on it to fund the build.
5. What warranty or supervision does the lender need?
Most lenders need a structural warranty or an architect's certificate to cover the build. This protects you, the lender and future buyers against major defects. Arrange it before work starts, because it often cannot be added later.
Self-build insurance, including site liability and works cover, is also important. Your lender will usually ask to see it. Speak to providers early, as some warranties require inspections at specific stages.
Building control sign-off is separate from the warranty and is also essential. Without a completion certificate, you may struggle to remortgage or sell later. Keep a tidy file of certificates, inspections and invoices from day one. Lenders and future buyers will ask for them.
6. Should I sort my mortgage before buying the land?
Yes, ideally. Speaking to a broker before you buy the plot helps you understand how much you can borrow and how funds will be released. Some lenders will fund the land purchase as the first stage, which may reduce the cash you need upfront.
You will also need a plan for how the project ends. Some borrowers remortgage onto a standard residential mortgage once the home is finished. Others use bridging finance for speed, which is expensive short-term borrowing and needs a clear exit. Self-build mortgages are FCA-regulated when you plan to live in the home. Developers building to sell or let should look at development finance instead.
A clear plan for land, build, cash flow and exit makes lenders more comfortable. It also gives you a better chance of finishing on time and on budget.
Self-build mortgagesStage-release mortgages to buy land and build or substantially renovate your own home.
Explore self-build mortgagesFrequently asked questions
Can I get a mortgage to buy land for a self-build?
Yes, some self-build lenders will fund the land purchase as the first stage of the mortgage, typically at a lower loan-to-value than the build. You usually need planning permission and detailed build plans. Without a firm build plan, lending on land alone is much harder to arrange.
How much deposit do I need for a self-build?
Lenders often fund up to around 75% of land and build costs, so you may need 25% or more from your own money. You also need cash for contingencies and, with arrears stage payments, to pay for each stage before the lender releases funds.
What is the difference between arrears and advance stage payments?
With arrears stage payments, the lender releases money after each build stage is completed and inspected. With advance stage payments, money is released before each stage begins. Advance products help cash flow but are offered by fewer lenders and may cost more.
Do I need a structural warranty for a self-build?
Most lenders require a structural warranty or an architect's certificate of practical completion. It covers major defects and helps when you sell or remortgage later. Arrange it before work starts, because many providers need to inspect the build at set stages.
Can I live in my current home while I build?
Yes. Many self-builders stay in their current home or rent during the build. Lenders will assess whether you can afford your existing housing costs alongside the self-build mortgage payments. Some borrowers sell first to release cash and reduce borrowing. Keep enough cash for both.
Is a self-build mortgage regulated?
A self-build mortgage is FCA-regulated when you, or a close family member, will live in the finished home. If you are building to sell or let, the borrowing is usually not FCA-regulated and may be arranged as development finance instead.
Important: This guide is general information, not personal advice. Rules, rates and lender criteria change; speak to an adviser about your circumstances. Your home may be repossessed if you do not keep up repayments on your mortgage.