The self-build mortgage is designed for those who want to build their own home rather than buying one already constructed. It is a specific mortgage product with different characteristics and requirements to a conventional mortgage, allowing you to finance both the land purchase and the construction of the property.
How does a self-build mortgage work?
Unlike a traditional mortgage, the capital is not delivered all at once but in partial drawdowns linked to construction progress. The bank releases money in phases, after certification by an architect confirming the percentage of work completed.
Typical drawdown phases:
- Phase 1: Land purchase (if not already owned)
- Phase 2: Foundations and structure
- Phase 3: Roof and enclosures
- Phase 4: Installations and finishes
- Phase 5: Final completion certificate and handover
During construction you only pay interest on the capital drawn down, which reduces the financial burden while the work is ongoing.
What do banks look at?
To approve a self-build mortgage, banks assess:
- Approved project — It is essential to have an architectural project approved by the relevant professional body before applying for the mortgage.
- Building permit — The local council must have granted the construction licence.
- Construction budget — The bank analyses the total cost of the work and compares it with a prior appraisal of the finished property.
- Land ownership — If you already own the land, conditions improve significantly. If not, the bank can also finance its purchase.
- Debt capacity — Monthly payments must not exceed 35% of net monthly income.
- Job stability — Permanent contract or established activity with demonstrable income.
- Available savings — Generally up to 80% of the total construction budget is financed.
What documentation do you need?
- Approved architectural project
- Municipal building permit
- Detailed material execution budget
- Land deed (if already yours)
- Last 3 payslips or tax return
- Income tax returns for the last 2 years
- Bank statements for the last 6 months
- Valid DNI/NIE
When is a self-build mortgage the right choice?
The self-build mortgage is one of the most complex products on the market. Not all banks offer it and those that do apply very different criteria. Duplo Capital knows exactly which institutions finance this type of project and under what conditions.
- You have or want to buy land and build to your specifications.
- You're looking for a customised home you can't find on the market.
- You want to control every detail of the construction process.
- The construction cost is lower than the market price of a similar existing property.
The Duplo Capital advantage
Duplo Capital negotiates simultaneously with over 20 institutions to secure the best conditions on your self-build mortgage — something you could not obtain by going directly to your bank.
Frequently asked questions about self-build mortgages
Yes, with a self-build mortgage, a specific product for people who want to build their own home rather than buy one already built. It can finance both the purchase of the land, if you do not own it yet, and the construction itself. Its requirements and the way it works differ from a standard mortgage. Not every lender offers it on the same terms, and approval depends on the project and on your profile.
The money is not paid out all at once but in partial drawdowns as the construction progresses. Before each release, an architect certifies the percentage of work completed. The usual stages are the land purchase, foundations and structure, roof and enclosure, installations and finishes, and the final completion certificate. During construction you only pay for the capital already drawn, which lightens the financial burden.
A self-build mortgage covers at most up to 80% of the total budget, so you will need at least 20% of your own funds. The final amount depends on the project valuation, against which the bank checks the construction budget. If you already own the land, the financing terms improve considerably. In any case, each lender applies its own criteria and the outcome depends on your profile.
You must have an architectural project approved (visado) by the relevant professional association and a building permit granted by the town council. The bank also checks that the construction budget is consistent with the project valuation. It then assesses your solvency: the instalment should not exceed 35% of the household's net income, and you need job stability and sufficient savings. Duplo Capital supports you at every stage so your application is presented as strongly as possible.
You will need documents about the project and about your financial situation. For the project: the approved architectural plans, the municipal building permit, the detailed construction budget and the land title deed if you already own it. For your profile: your last 3 payslips or your tax return, your income tax (IRPF) returns for the last 2 years, bank statements for the last 6 months and a valid DNI or NIE. The bank may ask for further documents depending on your case.
Yes, owning the land considerably improves the financing terms. If you do not own it yet, the land purchase can be included as the first stage of the self-build mortgage. In that case, the terms will depend on the value of the whole project and on your profile.
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