Mortgage guide
Self Build Mortgages: detailed guide
Explore self build mortgage options for borrowers building their own home, including custom builds and barn conversions.
- Published
- 13 Apr 2026
- Last reviewed
- 8 Oct 2026
- Reading time
- 2 min
Barn conversion mortgage
A barn conversion mortgage is a specialist form of property finance used to fund the purchase, conversion, or refinance of agricultural or redundant rural buildings into residential dwellings. These cases sit outside standard residential lending due to planning complexity, construction risk, and valuation methodology, and therefore require lenders with explicit appetite for conversion projects.
Development finance for self build
Development finance for self build is a specialist funding route used where a borrower does not meet residential affordability criteria, or where the intended exit is sale or cash repayment rather than long-term mortgage lending. It is fundamentally different from a self-build mortgage and is underwritten on project viability and exit strategy, not personal income.
Home renovation loan
A home renovation loan is a form of specialist property finance designed to fund significant refurbishment, structural alteration, or modernisation of an existing residential property. These loans sit between standard residential mortgages and full development finance, and lender appetite is driven by scope of works, property condition, and valuation risk.
Development finance calculator
Self build mortgage criteria
For context, these are the wider product terms covered by this guide. Availability and eligibility depend on your circumstances and the lender.
| Criteria | Detail |
|---|---|
| Loan to Value (LTV) | Varies by lender, assessed against the land value and the projected completed value |
| Build costs funded | Varies by lender and case, released in stages against build progress |
| Term | Set by the lender, subject to age and affordability |
| Repayment type | Interest only or repayment |
| Product options | Fixed, variable or base rate tracker, depending on the lender |
| Barn conversions | Yes, with lenders that accept conversion projects |
Related case studies
Frequently asked questions
How do self build mortgages work?
Self build mortgages fund the construction of a home instead of the purchase of a finished property. The loan is released in stages as the build progresses and is assessed on affordability, build costs and the projected value of the completed home.
Are self build mortgages regulated?
Usually, if the borrower intends to occupy the property as their main residence. Regulation by the Financial Conduct Authority then applies in the same way as for a standard residential mortgage. In law, a self build mortgage is a regulated mortgage contract where at least 40% of the property is used, or is intended to be used, as a dwelling by the borrower or a close family member.
How do you apply for a self build mortgage?
Applying for a self build mortgage involves providing planning consent, build costings, professional details and personal financial information. Lenders assess affordability, project viability and end value before issuing an agreement in principle.
Do you need a deposit for a self build mortgage?
Yes, a self build mortgage needs a deposit. It is commonly provided as cash, land equity or a combination of both, reflecting the higher risk compared with purchasing a completed property.
Are self-build mortgages more expensive?
They can be. Self build mortgages are often more expensive during construction because of the higher risk and the staged lending. Interest rates are usually higher than on a standard residential mortgage, but rates can reduce once the loan converts to a completed residential mortgage, and pricing varies by lender.
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