Ask whether the property supports the use you intend
Planning due diligence should test both the existing building and the buyer’s intended use. A dwelling that can continue to be occupied may not permit an extension, an additional apartment or tourist accommodation. A commercial unit fitted out as a home may look convincing while lacking an authorised residential use. Begin by describing what you intend to do and which features are essential to the purchase, so the enquiries address your actual decision.
Spain combines national land and registration rules with autonomous-community planning legislation, municipal plans and sectoral restrictions. A generic assertion that a property has “all licences” is therefore inadequate. Identify the relevant municipality, parcel and building history, then ask which instruments apply. A sound report separates existing authorisations, future permissions and unresolved enforcement questions instead of compressing them into a single green light.
Legal framework and sources: BOE · Texto refundido de la Ley de Suelo y Rehabilitación Urbana ↗
Read the planning classification and the detailed rules
Request current planning information for the exact parcel and identify the applicable plan, amendments and any relevant suspension or management instrument. Classification alone is insufficient. The detailed rules may address use, minimum parcel size, setbacks, height, density, building coverage and heritage protection. Establish whether the plot is ready for building or subject to urbanisation, land readjustment, transfers or outstanding infrastructure obligations.
A cadastral description as urban is not equivalent to municipal confirmation that a residential development can be carried out immediately. Nor does an existing neighbouring house prove that identical construction is permissible on your parcel. Ask a technician to compare the proposed project with the actual planning parameters and obtain written clarification of material uncertainty. Where the plan is changing, distinguish an approved rule from a proposal; the purchase should not depend on anticipated development rights being treated as already secured.
Legal framework and sources: BOE · Texto refundido de la Ley de Suelo y Rehabilitación Urbana ↗
Match the building licence with what was actually built
Obtain the licence, approved project and any authorised amendments. Compare the house’s footprint, floor count, area, use and ancillary structures with the approved documents. A licence for the original dwelling does not necessarily cover a later pool, garage conversion, enclosed terrace or additional floor. The purpose is to reconstruct the authorised building, then identify any divergence from the current property.
Check conditions attached to the permission and evidence that they were satisfied. These can concern access, services, sectoral approvals or technical requirements. A payment receipt for a municipal works tax is not the licence itself. Where only a summary or an illegible old copy is available, seek the underlying file or an appropriate municipal response. Do not infer a broad permission from a document whose subject, plans or conditions cannot be established reliably.
Legal framework and sources: BOE · Texto refundido de la Ley de Suelo y Rehabilitación Urbana ↗BOE · Ley 38/1999, Ordenación de la Edificación ↗
Completion and occupancy are distinct stages
A final works certificate is technical evidence about completion and conformity within its scope. The occupancy instrument addresses the administrative conditions for occupying or using the completed building under the applicable regional regime. Depending on location and circumstances, the process may involve a licence, responsible declaration or another instrument. Ask which one was required when the building was completed and which documentation is necessary for the transaction or proposed use now.
A responsible declaration should not be treated as an unconditional municipal endorsement merely because it was submitted. Review its supporting documents, scope and any subsequent inspection or adverse response. Similarly, an old occupancy licence may not cover a later conversion into several units. Trace the continuity between the authorised project, completion documentation and current configuration, and investigate any break rather than assuming that one historic occupancy document validates all subsequent changes.
Legal framework and sources: BOE · Texto refundido de la Ley de Suelo y Rehabilitación Urbana ↗BOE · Ley 38/1999, Ordenación de la Edificación ↗
Differentiate lawful nonconformity from unlawful building
A building may have been lawfully erected but become inconsistent with a later plan. Regional law may then limit works or define a particular out-of-planning status. That is different from construction undertaken without the necessary authorisation. The distinction matters for maintenance, alterations, rebuilding after damage, financing and resale. A short label such as fuera de ordenación does not explain the whole legal position.
Obtain the relevant administrative decision and identify the exact works or uses allowed. In Andalucía, for example, the statutory recognition of an assimilated out-of-planning situation does not legalise the irregular building. Its conditions and consequences must be read in the applicable framework. Do not transfer that regional terminology automatically to Murcia, Valencia, Madrid or the Balearic Islands. The report should explain what the status permits in practical terms and which proposed actions remain prohibited or conditional.
Legal framework and sources: BOE · Texto refundido de la Ley de Suelo y Rehabilitación Urbana ↗BOE · Ley 7/2021, ordenación territorial y urbanística de Andalucía ↗
Old works: registration is not a universal legalisation
Article 28.4 of the national land legislation allows a registration route for certain old constructions when the relevant legal conditions are met. It requires evidence of completion and description and involves checks concerning enforcement and protected interests. Royal Decree 1093/1997 also forms part of the registration framework. The applicable limitation rules depend on the territory, dates and type of land or infringement; there is no universal four-year rule for every building in Spain.
An architect’s or other competent technician’s certificate may support age and physical description. It does not alone establish that restoration powers have expired or that public-domain restrictions are absent. Examine protected land, coastal and water restrictions, easements and any enforcement history. Before agreeing a retention for an old-works declaration, confirm that the proposed route is legally available and distinguish its registration outcome from the building’s planning status afterwards.
Legal framework and sources: BOE · Texto refundido de la Ley de Suelo y Rehabilitación Urbana ↗BOE · Real Decreto 1093/1997, inscripción de actos urbanísticos ↗
Investigate enforcement and sectoral restrictions directly
Request information on enforcement proceedings, restoration orders, penalties and outstanding requirements that affect the property. Ask whether the response covers the whole parcel and all structures, and whether it is confined to current open files. A statement that no proceeding is pending is narrower than confirmation that every existing work is lawful. Keep that distinction visible in the acquisition report.
Planning permission also operates alongside coastal, water, roads, heritage, environmental and other sectoral rules. A municipal licence cannot be assumed to resolve every separate authorisation. Where the property lies close to a public boundary or protected area, obtain the competent authority’s information and have the geometry checked. Allocate responsibility between the legal adviser and technician so that a favourable legal reading is not based on the wrong parcel location, and an accurate map is not mistaken for the necessary administrative permission.
Legal framework and sources: BOE · Texto refundido de la Ley de Suelo y Rehabilitación Urbana ↗BOE · Real Decreto 1093/1997, inscripción de actos urbanísticos ↗BOE · Ley 7/2021, ordenación territorial y urbanística de Andalucía ↗
Negotiate a solution that matches the legal uncertainty
Where documentation is missing but a lawful route is established, require the seller to obtain it by an agreed date and define satisfactory completion evidence. If the issue concerns a proposed change of use or uncertain regularisation, consider whether the purchase should depend on the necessary decision. A promise to apply for a licence is not equivalent to obtaining it. The contract should state what happens if the application is refused or approved only on commercially unacceptable conditions.
Budget the complete remedy: technical work, municipal charges, physical alterations, notarial and Registry steps and any relevant taxes. A retention should reflect a supported estimate and clear control rules. Some defects cannot be priced adequately because they undermine the essential purpose of the purchase. A buyer seeking a family home should not be pushed into accepting an unapproved commercial unit merely because the seller offers a discount.
Legal framework and sources: BOE · Texto refundido de la Ley de Suelo y Rehabilitación Urbana ↗BOE · Real Decreto 1093/1997, inscripción de actos urbanísticos ↗BOE · Ley 38/1999, Ordenación de la Edificación ↗
An example: an old house with a recent guest apartment
In this fictional transaction, historic aerial photographs establish that the main house existed decades ago. The seller presents this as proof that every current structure can be registered by age. A site visit reveals a recently converted garage with a kitchen and bathroom. The old photographs establish the garage’s external existence, but do not establish when its residential conversion occurred or whether an additional dwelling is permitted.
The review separates the main house, garage structure and later change of use. It seeks the relevant plans, age evidence and municipal position for each. The buyer may still proceed if the guest space can lawfully serve the intended purpose, but should not rely on the age of the original shell to justify the later residential use. This distinction can affect financing, insurance, occupancy documentation and the price that the property reasonably supports.
Legal framework and sources: BOE · Texto refundido de la Ley de Suelo y Rehabilitación Urbana ↗BOE · Real Decreto 1093/1997, inscripción de actos urbanísticos ↗BOE · Ley 38/1999, Ordenación de la Edificación ↗
Read the Valencian Community guide to planning infringements →
Sources & further reading
BOE · Texto refundido de la Ley de Suelo y Rehabilitación Urbana ↗BOE · Real Decreto 1093/1997, inscripción de actos urbanísticos ↗BOE · Ley 38/1999, Ordenación de la Edificación ↗BOE · Ley 7/2021, ordenación territorial y urbanística de Andalucía ↗BOE · Ley Hipotecaria ↗Editorial preview: professional legal review is pending. This guide provides general information and does not determine the legal position of a particular property.
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