Illegal Builds in Spain — What to Check Before Buying

Spain experienced a construction boom from the late 1990s to 2008, during which planning controls were inconsistently enforced. Developers, and individual owners alike, routinely built extensions, swimming pools, garages, and even entire houses without proper licencia de obras (building licence). In rural areas, homes were constructed on agricultural land where residential use was technically prohibited.

The problem is particularly acute in Andalusia, the region that includes the Costa del Sol. Estimates suggest that tens of thousands of properties across the region have some form of planning irregularity — ranging from minor (an unlicensed terrace enclosure) to severe (an entire house built on protected land).

After the 2008 financial crisis, Spanish authorities began enforcing planning regulations more strictly. High-profile demolition cases — including the Cantoria and Algarrobico cases — brought international attention to the issue. For UK buyers, the message is clear: never assume a property is legal just because it exists, looks finished, and has people living in it.

Even properties listed for sale by reputable estate agents can have planning issues. The agent is not legally required to verify planning status, and many do not. This is why independent legal advice from your own property lawyer is non-negotiable.

A competent Spanish property lawyer (abogado) should carry out the following planning and construction checks before you commit to purchasing:

• PGOU check (Plan General de Ordenación Urbanística): This is the municipal urban plan that classifies every plot of land. Your lawyer must verify that the property sits on suelo urbano (urban land) or suelo urbanizable (land designated for development), not suelo rústico (rural/protected land) where residential construction may be prohibited.
• Building licence verification: Confirm that the original construction has a valid licencia de primera ocupación (first occupation licence) or licencia de obras. Without this, the property was never legally authorised.
• Catastro vs Registro comparison: The Catastro (tax office register) and the Registro de la Propiedad (Land Registry) should broadly agree on the property's size, boundaries, and built area. Significant discrepancies — for example, the Registro showing a 100m² house but the Catastro recording 160m² — indicate undeclared extensions.
• Physical inspection vs registered area: Compare what is physically built on the ground with what appears in the official records. A swimming pool, garage, or extra bedroom that does not appear in the escritura (deed) or Catastro is a red flag.
• Planning infringement history: Check with the town hall (ayuntamiento) whether any enforcement actions, complaints, or demolition orders have been filed against the property.

If your lawyer does not routinely perform all of these checks, find a different lawyer. See our glossary for explanations of these Spanish terms.

Watch out for these warning signs when viewing properties on the Costa del Sol:

• No first-occupation licence — The seller cannot produce a licencia de primera ocupación. This is the single biggest red flag.
• Property larger than registered — The actual built area exceeds what is recorded in the escritura or Catastro by more than 5–10%.
• Swimming pool not on plans — Pools require a licence in Spain. If the pool does not appear in the Catastro records, it was likely built without permission.
• Located on suelo rústico — Rural land, especially near protected areas (national parks, coastline, riverbeds). Be extremely cautious with country fincas.
• Unusually low price — If a property seems too cheap for its size and location, planning problems are a common reason.
• Seller resists due diligence — Pressure to sign quickly, reluctance to provide documentation, or suggestions that "everyone builds like this" are serious warning signs.
• No certificado de eficiencia energética (energy certificate) — Required by law for any sale. Its absence may indicate wider compliance issues.
• Utility connections via neighbouring property — If electricity or water is supplied through a neighbour rather than directly from the utility company, the property may lack official habitation status.

If any of these red flags apply, do not walk away immediately — some issues are resolvable — but insist on a thorough investigation before proceeding.

Andalusia introduced the AFO certificate (Asimilado a Fuera de Ordenación) to address the backlog of older illegal constructions. The AFO does not make a property fully "legal" in the traditional sense — it recognises that the building cannot be demolished because the enforcement period has expired, and it grants the property a quasi-legal status that allows it to be registered, sold, mortgaged, and connected to utilities.

Key requirements for an AFO:

• The construction must have been completed more than 6 years ago (the limitation period for planning enforcement in Andalusia)
• The building must not be on specially protected land (green belt, coastal, national park, public domain, etc.)
• No active demolition order or enforcement proceedings must be in place
• A technical report from an architect confirming the building's structural safety is required

AFO costs: Expect to pay approximately €3,000–8,000 in total, including the architect's report (€1,000–2,500), town hall fees (€1,000–3,000), and legal fees. The process typically takes 3–6 months.

An AFO allows you to register the property's true dimensions in the Land Registry and Catastro, obtain or regularise utility connections, and sell the property in the future with clear documentation. However, you should be aware that the property will carry the fuera de ordenación notation permanently, which means you cannot extend or significantly renovate the building — only essential maintenance and repairs are permitted.

Illegal or partially illegal construction has direct consequences for both insurance and mortgage finance:

Insurance:

• Most Spanish insurers will cover the property's registered area only. Unregistered extensions, pools, or outbuildings may not be covered, leaving you exposed in the event of fire, flood, or structural damage.
• If a claim arises relating to an unlicensed structure, the insurer may refuse to pay out entirely.
• Buildings liability insurance (seguro de responsabilidad civil) may be void if the property does not comply with planning regulations.

Mortgages:

• Spanish banks commission their own valuation (tasación) before approving a mortgage. The valuer will note any discrepancies between the physical property and the registered dimensions.
• If significant illegal construction is identified, the bank will typically reduce the valuation to reflect only the legal portion, or refuse the mortgage altogether.
• Properties on suelo rústico without proper licences are extremely difficult to mortgage through Spanish banks.
• Even with an AFO certificate, some banks may apply a lower loan-to-value ratio (50–60% instead of the standard 60–70% for non-residents).

The takeaway: buying an illegal build does not just risk demolition — it also limits your ability to insure, finance, and eventually resell the property. Proper due diligence upfront is far cheaper than dealing with problems later. For more on the purchase process, see our step-by-step buying guide.

Countryside properties — fincas, cortijos, and rural houses — are particularly high-risk for planning issues. Many were built decades ago on agricultural land, with no formal building licence, and passed through generations without anyone questioning their legality.

Key risks with rural properties:

• Land classification: Many fincas sit on suelo no urbanizable (non-developable land). Even if the house has been there for 50 years, its legal status may be precarious.
• Minimum plot size: Andalusian planning law typically requires a minimum plot size of 2,500m² to 10,000m² (depending on the municipality) for rural construction. If the plot is too small, the build may be inherently unlicensable.
• Water and electricity: Legal rural properties should have their own water supply (well with extraction licence) and electricity connection. Informal connections are a warning sign.
• Access rights: Ensure the property has a legally registered right of access. Many rural properties are reached via tracks that cross neighbouring land without any formal servidumbre de paso (right of way).

This does not mean you should avoid rural properties entirely — many beautiful, fully legal fincas exist, and an AFO certificate can resolve issues with older builds. But you must engage a lawyer experienced in rural property and insist on comprehensive planning checks before committing a single euro. Use our cost calculator to budget for the additional legal and survey costs that rural purchases typically require.