In Spain, there are thousands of properties that, for various reasons, do not have all the required permits or licences. These may include older buildings constructed before stricter urban planning regulations were introduced, undeclared extensions, or even works carried out without a municipal permit. Legalising a property is not only important to comply with the law, but also to avoid fines, facilitate the sale or rental of the property, and ensure access to basic utilities.

This article explains step-by-step how to legalise a property in Spain, the process involved, and the documents typically required, with a particular focus on old constructions, unlicensed works, and the regularisation of extensions.

1) Initial assessment: determining the planning status

Before starting any process, it is essential to understand the legal and planning status of the property. This analysis usually includes:

• Land Registry: checking ownership, encumbrances, and the registered description.
• Cadastre: verifying cadastral reference, built surface, usage, and location.
• Municipal planning: requesting a planning report or consultation from the town hall.
• Construction date: gathering evidence (invoices, photos, contracts, technical certificates) to prove the age of the building.

With this “legal map” you can determine whether the property can be legalised, which procedure applies, and any limitations.

2) Older constructions: prescription and AFO-type procedures

Many irregular properties are old enough to fall within the prescription period for planning infringements (the time limit varies by autonomous community). In such cases, full legalisation as if with an original licence is not possible, but a recognition of existing status can be obtained, such as the Spanish Asimilado a Fuera de Ordenación (AFO) or equivalent local arrangements.

This usually requires:

• Technical certificate of age, safety, health, and stability.
• Report or technical statement justifying compliance with minimum requirements (access, sanitation, utilities, etc.).
• Payment of municipal fees and taxes.

The result: the property is “regularised in practice” (with planning restrictions), providing security for its use and for future transactions (sale, inheritance).

3) Regularising undeclared extensions or renovations

If there are extensions (enclosed terraces, additional floors, garages, porches) not included in the original licence, the actual physical and legal situation must be updated in official records:

1. Survey and plans prepared by a qualified technician (architect/technical architect).
2. Report or project as required by the municipality (legalisation of minor/major works).
3. Municipal validation and payment of fees.
4. Updating the Cadastre and, if applicable, the Land Registry.

This ensures the official record matches the reality, avoiding problems when selling or insuring the property.

4) Properties built without a licence (not prescribed)

This is the most complex scenario. If the construction is recent and has no licence, the town hall may impose fines and, in some cases, order a restoration of legality (demolition or adaptation).

To attempt legalisation, at least these conditions must be met:

• The use and volume must comply with the current planning regulations.
• It must be possible to apply for a retrospective building licence with a complete technical project.
• The building must not be located on protected non-developable land or in areas with strict restrictions (coastal zones, rivers, roads, heritage sites, etc.).

If any of these requirements are not met, legalisation may be very limited or impossible.

5) Commonly required documentation

• Title deeds and updated Land Registry extract.
• Cadastral reference and graphical data.
• Technical project / technical statement and certificates of safety, habitability, and age.
• Plans (current state and, if applicable, legalisable state).
• Photographic report and proof of age (invoices, contracts, sworn statements, etc.).
• Proof of payment of municipal or regional fees and taxes.

6) Special cases: protected land, coastal areas, and restrictions

Properties in specially protected areas (natural parks, maritime-terrestrial public domain, riverbanks, roads, historical heritage) face very strict limitations. In such locations, legalisation is often impossible or only allowed under very specific conditions. It is essential to verify this before starting any procedure.

7) Costs, timelines, and fees (indicative)

Costs depend on the technical scope (plans, reports, project), municipal fees, and any regional taxes. Timelines vary depending on the town hall’s workload and the complexity of the file. It is advisable to allow extra time for additional requests and for coordinating updates to the Cadastre and Land Registry.

8) Benefits of legalisation

• Legal security for use, sale, inheritance, and financing.
• Access to utilities (water, electricity, gas) and municipal services.
• Increase in value and improved marketability of the property.
• Reduced risk of fines or enforcement measures.

9) Quick checklist: key steps

1. Gather title deeds, registry extract, and cadastral reference.
2. Request a municipal planning report or consultation.
3. Commission a technician to prepare the survey, plans, and certificates.
4. Define the appropriate route: AFO/equivalent, work legalisation, or retrospective licence.
5. Submit the application and respond to any requests.
6. Update the Cadastre and, if necessary, the Land Registry.

Conclusion

Legalising a property in Spain is achievable with a proper diagnosis and by following the appropriate route based on the age of the construction, its planning compatibility, and local regulations. For older buildings, prescription may allow recognition as AFO or similar; for undeclared extensions, the key is to update and validate the existing situation; and for recent works without a licence, everything depends on compliance with planning and the possibility of obtaining a licence with a complete technical project.

Acting in time protects your investment, avoids fines, and facilitates future transactions such as sale, inheritance, financing, or rental. If your property has irregularities, start with an analysis and a clear technical-legal plan.

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