Self Build Mortgages > Best Self Build Rates

Best Self Build Mortgage Rates in the UK 2025

Why are Self Build Mortgage rates different from standard mortgage rates?

It all comes down to risk. From a lender’s point of view, a self build mortgage is more complex and comes with more unknowns:

  • There’s no physical house to secure the loan against at the start

  • Delays, planning issues, and overspending are all common

  • The property value can change during the build

Because of this, self build mortgage rates are usually 0.5% to 1.5% higher than traditional mortgage rates.

That said, once your build is complete, you may be able to remortgage to a standard product with a lower rate.

How do Self Build Mortgage rates work?

Self build mortgage rates work differently to standard mortgage rates because the loan is released in stages, rather than as a single lump sum. That means the lender is taking on more risk, and so the rates are usually a bit higher.

You’ll typically pay:

  • Interest-only payments during the build. This helps keep costs lower while your home is still under construction.

  • Full repayments (interest + capital) once the property is complete and signed off.

There are two types of self build mortgages:

  • Arrears stage payment mortgages, where funds are released after each build stage is completed.

  • Advance stage payment mortgages, where funds are released at the beginning of each stage.

Each type can affect your mortgage rate. Advance payment mortgages often have slightly higher interest rates, but can improve cash flow if you don’t have large savings upfront.

What impacts the self build mortgage rates you’re offered?

Stage payment type

Advance stage payments typically come with slightly higher rates due to the increased upfront risk for the lender.

Lender policies

Each lender has its own risk appetite. Some specialise in self build mortgages and offer more competitive rates.

Deposit size

Most self build lenders will want a deposit of at least 25-30%. The more you can put down, the better your rate will usually be.

Build type

Some construction methods are seen as higher risk, which can impact your rate or narrow down your lender options.

Your credit history

A clean credit score gives lenders more confidence in your ability to repay the loan.

What are the current Self Build Mortgage rates in 2025?

At Mayflower Mortgage, we work with specialist lenders to offer some of the most competitive self build mortgage rates in the UK.

You can also see our latest Self Build Mortgage Rates on our Self and Custom Build page.

Tips to get a better Self Build Mortgage rate

Start early

The more time you have, the more choice you’ll get.

Improve credit score

Even a small bump can impact your rate.

Have a detailed plan

Lenders want to see costs, stages and contingencies.

Speak to a broker

We know who offers what rates.

Why work with Mayflower Mortgage?

We’re proud to be named the "Best Self Build Mortgage Advisory Firm 2025" at the Design and Build Awards. We’re also a finalist for "Best Specialist Broker " at the 2025 Mortgage Strategy Awards and Finalist for Best Specialist Broker at The Financial Reporter Awards 2025.

We work with clients across the UK to:

  • Compare rates from self build lenders on the market

  • Match you to the lender that best suits your build and budget

  • Handle the application from start to finish

  • Give you access to Self Build Saver Solution

  • Winner badge

    Best Self Build Mortgage Advisory Firm

    Design and Build Awards 2025

  • Finalist badge

    Best Specialist Broker

    Finalist at the 2025 Mortgage Strategy Awards

  • Best Specialist Broker

    Finalist at the 2025 Financial Reporter Awards

Want to see the latest Self Build Mortgage rates?

We update our live mortgage rates regularly, so you can always check out the latest information. Head over to our Self Build Mortgage Rates table to see today’s options.

What are you looking to do next?

Frequently asked questions

  • Self builds are seen as higher risk by lenders, especially because the property doesn’t yet exist. This often results in higher interest rates to reflect the extra risk and complexity involved.

  • In many cases, once the build is complete, you can remortgage onto a lower ‘traditional’ mortgage rate. This is a common way to save money long-term and improve affordability once the project is done.

  • Some lenders offer fixed-rate self build mortgages from time to time. Most rates are variable.