Self‑Build Mortgage Advice: How it All Works

• A self-build mortgage isn't like a standard home loan; the funds aren't released in one go, but in stages
• Lenders do factor in extra risk with self-build homes, but the correct plan and a reasonable deposit will see the rates comparable to a standard home mortgage.
• Get a mortgage broker to prevent any log jams during the process.

Building your own home is a dream many people have, but often, it doesn’t get past the financing stage. It’s where plans like these falter, mainly because of a lack of understanding when it comes to self-build mortgages - the specialist loan category for this very purpose.

The latest figures show that just under 65,000 people are currently on the government’s custom-build register - most of whom will be doing their best to achieve their dream home with as few hitches as possible.

If you’re thinking of buying a serviced plot, understanding this side of things also matters a lot. So, stick around, as we shine a light on what lenders want from you and what to expect beyond that.

What Is a Self-Build Mortgage?

A self-build mortgage usually needs to cover both the purchase of the plot and the actual construction of your home. However, it doesn’t typically work anything like a standard house loan. Instead of releasing all the funds in one go, lenders release the money in stages - in line with your progress.

How are funds often released?

There are two ways that a self-build mortgage can be paid:

• Arrears: This is the most common payment method for a self-build home. After each stage, you'll be reimbursed by the lender once they are satisfied that this stage is complete.
• Advance payments: Useful for those with low savings. The lender releases the funds at the start of each stage.

What is often overlooked?

Knowing what's expected before you start talking to lenders puts you in a much stronger position. Here are a few things that often get overlooked.

• Professional fees, like architects or project managers, can sometimes be rolled into the loan, which takes some of the pressure off early project costs
• Most lenders want detailed build plans and full cost breakdowns before they'll agree to anything, so having these ready speeds up the whole process up
• Independent inspections may be required before each stage of funding is released, so build these into your timeline from the start
• Getting legal checks done on the plot early stops planning or construction from hitting a wall further down the line
• If you're building something out of the ordinary (modular, off-grid, or unconventional in any way), there are mortgage products built specifically around that
• The process typically takes much longer than a regular mortgage, so factor that into your timeframe.

A broker who knows self-build lending finds you lenders who actually understand how these projects work and can structure the mortgage around your timeline.

Are Self-Build Mortgage Rates Higher Than Standard Ones?

It’s common for people to worry that a self-build mortgage will cost you significantly more than a standard home loan. In reality, the difference isn’t usually that big. Lenders do factor in extra risk, but a solid plan and a reasonable deposit can make the rates very competitive. As of 2025, self-build mortgages are 0.5% to 1.5% more expensive than standard mortgages.

For instance, someone buying a serviced plot with detailed costings and a clear build timeline might pay only slightly more than they would for a conventional mortgage. Using a good mortgage broker can make a big difference, as they can find lenders who properly understand self-builds.

With the right combination, financing your self-build doesn’t have to be stressful - and you won’t be overpaying on interest.

Do I Actually Need a Self-Build Mortgage Broker?

Self-build projects can be incredibly rewarding, but rushing in without proper, expert support can lead to costly mistakes. Many borrowers don’t realise that there’s a lot to scrutinise, like project plans, cost estimates, and drawdown schedules.

Missing a detail early can create a log jam later, and the right broker can ensure you avoid all kinds of issues, like:

• Not having a clear, staged build plan approved by your lender
• Underestimating costs or leaving no room in the budget for the unexpected
• Buying a plot without checking service connections or planning permissions
• Failing to time mortgage drawdowns around actual construction milestones
• Skipping professional conveyancing on the plot purchase

Get these things right from the start, and the project stays on track. Get them wrong, and you might be looking at one problem after another. However, with a great broker and proactive steps, you should be able to keep things moving nicely.

A self-build can throw a lot at you all at once, but having the right people behind you from the beginning can make all the difference. A free consultation with one of our mortgage advisors will give you a clear picture of what type of loan suits your project and whether it’s a viable proposition.

At SAM Conveyancing, we handle self-build plot purchases across England and Wales every day, and our solicitors are on 99% of mortgage lender panels. What’s more, our web portal lets you handle everything in one place.

Get in touch today, and we’ll tell you exactly what's involved, what it costs, and how long your specific situation is likely to take.

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