Off-site Build Mortgage (Advanced Payment)
in partnership with
Mayflower Mortgage & Finance
Some off‑site homes need funding earlier in the process — and we’re here to help. Our Off‑site Build Mortgage (Advanced Payment) is designed for projects where your supplier requires funds upfront, giving you the confidence to move ahead with manufacturing.
With borrowing up to 80% LTV, flexible repayment options and rewards for an Energy Performance Rating of EPC B (88+), it’s a simple and sustainable way to build your off‑site home.
Your home may be repossessed if you do not keep up repayments on your mortgage
Heat Pump Cashback
Thinking about undertaking an energy-efficient self-build project or upgrading your home’s heating system? If you’re planning to install an air or ground source heat pump, you can claim for a £500 or £1000 cashback when you apply for a new mortgage at Ecology.
We offer a cashback for eligible residential mortgage applications for projects that include the installation of a heat pump. If you qualify, you can claim:
- £500 cashback for when you install an air source heat pump.
- £1,000 cashback for when you install a ground source heat pump.
To be eligible:
- Make sure that your installer is MCS accredited
- This offer applies to our self-build, renovation, conversion and shared ownership mortgages
- Your property must have existing loft and cavity wall insulation.
How to obtain the cashback
The process is simple and part of the mortgage process.
- When speaking to your appointed mortgage broker or one of our mortgage advisors, they will check your eligibility for the cashback.
- The cashback value and installers accreditation requirements and how to claim will be shown in your personalised illustration and any Offer of Loan.
- The cashback is payable within 18 months of completing your mortgage (i.e. when you receive your first stage release/advance) and with the production of an MCS installer certificate.
- The cashback will be paid when we receive a completion certificate confirming that the heat pump has been installed by an approved installer. If you qualify, your cashback will be paid into the bank account you use to make your monthly mortgage payments.
Other important information
Ecology is not responsible for ensuring the quality of the work carried out and the costs provided. You should carry out your own checks to ensure the costs and the supplier is suitable. If you find that you are not happy with the work carried out, you should speak to your supplier in the first instance. If the work carried out is covered under a scheme provider you should also contact the appropriate provider.
An example of a scheme provider is the Microgeneration Certificate Scheme (MCS) that are the standards and quality assurance organisation for renewable heat technologies such as solar thermal, air/ground source heat pumps and biomass boilers.
C-Change: Energy Efficiency Rewarded
We reward energy efficiency with our C-Change discount—because building a better future should benefit you too. Improve your property’s energy rating and you’ll not only cut energy bills and reduce your carbon footprint, but you could also secure a lower mortgage rate.
94% of our residential mortgage customers qualify for C-Change. It’s our way of saying thank you for making a positive change
How it works:
Take out your mortgage with Ecology
Build your new home or upgrade an existing property
Share your revised energy rating—we’ll calculate your discounted rate
Mortgage Calculator
Work out how much you could borrow and compare monthly payments.
FAQs
If you’re planning to build an energy-efficient off-site construction property, we’re here to help.
At Ecology, we’re not put off by the construction type; we’ll support many types of construction techniques.
Our mortgages are available throughout the UK (England, Scotland, Wales and Northern Ireland).
This mortgage is only available through Mayflower Mortgage & Finance. Please see Mayflower Mortgage & Finance FAQ for further details.
Off-site Build Mortgage (Advanced Payments) – we’ll release up to 80% of the purchase price or value of the property and subsequently, up to 80% of the final value of the property to help you cover your build costs.
We recognise that some customers experience cashflow issues when suppliers require high, upfront payments to pay for their property being built in a factory off-site with the property later mobilised on your land. With our innovative advanced payment mortgage, when your build manufacturer requires payment for the kit deposit, manufacturing, construction and delivery, this mortgage will provide payments up to 80% of the cost value. This ensures you have adequate cashflow to cover the cost of your build.
This type of mortgage may be suitable if you have limited deposit remaining after you have purchased the land and covered some of the infrastructure costs to the land.
As a building society with a unique mission to build a greener society, we lend on projects and properties that support our aims through their reduced impact on our environment. Making your home energy efficient is a major way you can support tackling climate change – while saving on your energy bills.
We reward borrowers whose properties are energy efficient (therefore have lower carbon emissions) with our C-Change discounts off our Variable Rate which helps them save money on their mortgage. We call our discounts ‘C-Change discounts’ simply because we’re aiming to make a ‘sea-change’ of difference to our climate with each property or project we fund.
The level of our C-Change sustainable homes or C-Change retrofit discount that applies is based on the Energy Standard rating achieved on the self-build, off-site build, renovation or conversion when the work is completed. Our C-Change energy improvements discount is based on the qualifying energy measures being installed. The discount is applied from the date we receive evidence that the work has been completed and if applicable the Energy Standard rating required has been achieved.
We’ve carefully selected Mayflower Mortgage & Finance as our exclusive off-site build partner.
A word from Mayflower: ‘Mayflower Mortgage & Finance are award-winning specialists in self-build, renovation and development finance. Having supported thousands of construction projects, we help clients secure funding, navigate lender requirements and structure their projects for success. With access to specialist lenders, exclusive products, industry-leading tools and expert guidance throughout the build journey, we provide far more than a mortgage – we give clients the support, knowledge and confidence needed to turn ambitious building projects into reality. Our focus on exceptional service and construction finance expertise has made us a trusted partner for self-builders across the UK’
What is off-site construction?
Off-site construction is sometimes referred to as modular or Modern Methods of Construction (MMC) housing. It’s constructed off-site, normally in a factory with your property then transported to your land and constructed in a very quick, accurate and energy-efficient manner.
Is this off-site build mortgage available through all suppliers?
Our Off-site Build Mortgages are only available when you are purchasing your build through Mayflower Mortgage & Finance.
Is the offsite build mortgage suitable for me?
We offer a range of mortgages to accommodate all customer types. We recognise that significant, upfront payments are required to the manufacturer to ensure the property can be funded and build off-site. We identified this as a general problem in the off-site market which is why we developed our innovative off-site build (advanced payment) mortgage.
Do I need to provide planning permission for my build?
Yes. We need at least outline planning permission to start the application process and detailed planning permission before the mortgage is released.
What information do I need to progress a mortgage application?
You’ll need to have a specific plot and build in mind which needs to be supported by detailed plans, including a breakdown of the building contract costs provided from your building manufacturer.
What deposit do I need for my build?
You need a 20% minimum deposit to buy the land and a further 15% – 20% of total build costs to start your build. The level of deposit you have available will determine which off-site build mortgage you take from our mortgage range.
Do I still need a deposit for my build if I already own the land and have planning permission?
No, you don’t always need a deposit; we can lend based on the value of your land to start the build, providing you already own the land and it’s mortgage-free. Also, if you need us to, we can help you repay any outstanding finance on the land.
How long do I have to complete the build?
Subject to planning constraints, we allow a maximum of 2 years for you to complete the self-build, although we encourage you to complete earlier to benefit from our C-Change sustainable homes discount which is applied to our Standard Variable Rate from the date we receive evidence that both the work has been completed and the Energy Standard rating required has been achieved.
Can I have interest-only during the build phase?
We offer an interest-only mortgage only when you have a qualifying repayment vehicle to support this for example an established ISA, endowment policies or Pension Plan.
Does the build property have to be my main residence?
Yes. Please bear in mind that the property can’t be a second or holiday home or classed as mobile planning.



