Seguro decenal in Spain: the 10-year new-build warranty foreign buyers can (and should) actually claim on (2026 guide)

A Dutch couple buys a €430,000 duplex in a 2019 promotion east of Valencia. The developer is a mid-sized regional operator with a decent reputation. Everything looks fine at handover — the acta de recepción is signed, the cédula de habitabilidad is issued, the IBI transfers into their name. Two winters later, in early 2024, water starts appearing along the north-facing kitchen wall every time it rains hard. By spring the paint is bubbling and the interior render has begun to crumble. They call the developer. The developer's legal representative sends a polite email confirming that the property is out of the 3-year seguro trienal warranty period (habitability defects, 3 years from acta de recepción) and suggests they file a claim on their home insurance instead.

The couple almost does. Their local administrador de fincas stops them: "This isn't a habitability issue. This is a moisture-barrier failure at the foundation-wall junction. That's a structural defect. You're still inside the ten years. This goes to the seguro decenal." Fourteen months later the insurer pays €38,400 to remediate the moisture barrier, re-render the affected walls, and replace two kitchen cabinets destroyed by mould. The developer never contributes a euro. The couple never files on their home insurance. The policy that pays is one they didn't know they had.

That story — repeated in some version thousands of times per year across Spain — is what the seguro decenal is for. It is one of the strongest legal protections a foreign buyer of a new-build property in Spain has, and one of the least understood. This guide walks through what it is, how the three warranty tiers stack together, how to check the policy actually exists before you sign, how to file a claim, and the specific defects where the coverage silently fails.

The three warranty tiers set out in Ley 38/1999 (LOE)

Every new-build home in Spain — every obra nueva — is covered by a three-tier warranty regime established by Ley 38/1999 de Ordenación de la Edificación (the LOE). The three tiers stack on top of each other and are structured by the type of defect:

Tier	Warranty name	Duration	What it covers	Who is liable
1	Seguro / responsabilidad anual	1 year from acta de recepción	Finish defects: paint, tiling, plasterwork, joinery, fittings	The builder (constructor) directly — no mandatory insurance
2	Seguro / responsabilidad trienal	3 years from acta de recepción	Habitability defects: damp, insulation, ventilation, acoustic failures, systems that don't function to spec	The builder and developer jointly — mandatory insurance since 2000
3	Seguro decenal	10 years from acta de recepción	Structural defects that compromise the estabilidad or resistencia mecánica of the building	The developer (promotor) — mandatory insurance under Art. 19 LOE

The seguro decenal is the tier most people mean when they say "the 10-year warranty on Spanish new-builds", but the other two matter — and the boundary between tier 2 and tier 3 is often where the real fight lives. A damp wall could be a habitability defect (year 3 window) or a structural moisture-barrier failure (year 10 window). Which tier applies decides whether you have a claim.

Three points about the tier structure that foreign buyers routinely misunderstand:

• The 10-year clock starts at the acta de recepción de la obra — the formal handover from the builder to the developer — not at your escritura. In practice these are usually days or weeks apart, but on a stalled promotion where the developer sat on completed units for two years before selling them, your effective coverage window can be substantially shorter than you assume. The acta de recepción date is on the libro del edificio (see below); check it.
• The three tiers are cumulative, not exclusive. A defect that appears at month 30 could theoretically fall under tiers 1, 2, or 3 depending on its nature. Your claim goes to the tier that fits the defect, and your right to claim under a shorter-tier warranty doesn't extinguish your right under a longer one.
• All three run from the same date. Not from "when the defect appeared" and not from "when the developer told you it was your problem". From the acta de recepción.

What the seguro decenal actually covers (and doesn't)

Article 17 of the LOE defines the covered defects as those that:

…afecten a elementos estructurales del edificio y comprometan directamente su resistencia mecánica y estabilidad.

In practice — reading the case law of the Tribunal Supremo across the last 15 years — the seguro decenal has been held to cover:

• Foundation defects. Settlement cracks, differential settlement, foundation-slab movement, ground-improvement failures on soft or fill soils.
• Load-bearing structure defects. Cracks in load-bearing walls, columns, beams, floor slabs (forjados) that compromise structural integrity. This is where aluminosis claims land when the affected building is under 10 years old (rare, but it happens).
• Roof structural failures. Distinguish carefully from finish defects: a leaking tile is tier 1; a sagging truss or failed structural insulation-support member is tier 3.
• Moisture-barrier and waterproofing failures at structural elements. Foundation-wall junctions, roof-slab waterproofing, terrace waterproofing on top of a habitable room — these are structural in the LOE sense because they compromise the building's ability to remain habitable and protect its load-bearing elements from water damage.
• Thermal-bridge failures that cause structural condensation damage. Where a design or execution error creates persistent condensation that damages structural elements.
• Systemic concrete failures. Poor concrete mix, insufficient rebar cover, incorrect curing that leads to spalling and reinforcement corrosion in load-bearing elements.

What the seguro decenal does not cover, and where insurers routinely deny claims:

• Aesthetic cracks that don't compromise structural integrity. Hairline cracks in interior plaster, shrinkage cracks in non-load-bearing walls — these are finish defects (tier 1) or nothing at all.
• Defects caused by owner alterations. If a previous owner knocked down a load-bearing wall (permitted or not) and the resulting movement causes a claim, the insurer will decline.
• Defects caused by fuerza mayor. Earthquakes above the norma sismorresistente threshold, exceptional floods, wildfires — these fall to the standard home insurance market.
• Systems installations — heating, plumbing, electrical, air conditioning — even when the failure damages structural elements. These sit in the tier 2 window and, after 3 years, are the owner's problem.
• Cosmetic damp — a leaking pipe under a sink that stains a wall is not a seguro decenal claim, even if it happens in year 4.

The line between tiers is contested and litigated. This is why the way you frame a claim in the initial comunicación fehaciente matters as much as the underlying defect.

Confirming the policy exists — before you sign the escritura

This is the single most important paragraph in this guide.

Since 6 May 2000 (LOE Art. 19.1.c and the linked disposiciones adicionales), the developer of any new residential building in Spain is legally required to contract a seguro decenal policy before selling any unit. The developer cannot obtain the declaración de obra nueva terminada — the notarial declaration that the construction is complete — without producing evidence of the policy to the notary. In theory this makes the policy check foolproof.

In practice, three loopholes exist and foreign buyers walk into all three:

1. Self-promoted single-family homes exempt. Under LOE Art. 19.1 second paragraph, the seguro decenal is not mandatory when the developer is a persona física (private individual, not a company) building a single home for their own use, provided they are not selling it during the coverage period. If they subsequently sell — even at year 2 — they must retroactively contract the policy or offer the buyer a written waiver. Most private-build sellers do not do this. Foreign buyers routinely purchase such properties without a seguro decenal and only discover the gap when a structural defect emerges.
2. Pre-2000 builds have no policy at all. The LOE 10-year insurance requirement only applies to buildings whose licence was granted after 6 May 2000. A building "completed in 2001" whose licence was granted in 1998 may not have a seguro decenal — check the licencia de obras date, not the acta de recepción.
3. Off-plan buyers who complete before the promotion is finished may have no policy at that moment. The insurance is contracted before the final declaración de obra nueva terminada. If you sign your escritura against a partial delivery — with communal areas still unfinished — the policy may not yet be in force. This is unusual but happens on distressed promotions.

Before you sign your escritura for any new-build purchase, ask your lawyer to obtain from the developer, in writing:

• A copy of the certificado de la póliza de seguro decenal, showing the policy number, the insurer's name, the coverage limits, and the effective date.
• Confirmation of the acta de recepción de la obra date — this is your 10-year clock start.
• The nota simple registral of the building (not just your unit) showing the seguro decenal is annotated in the property registry against the building as a whole.
• The libro del edificio — the mandatory building manual (LOE Art. 7) that includes the seguro decenal certificate, the ITE / IEE schedule, and the maintenance obligations.

If any of these four documents are missing, do not sign. This is not a procedural nicety — it is your only proof, ten years from now, that you have a claimable policy.

For off-plan purchases and bank-owned properties, the same rule applies with extra care: on bank-owned inventory that has passed through a servicer, the libro del edificio is frequently mislaid and reconstructing the seguro decenal trail is a nightmare when a claim arises.

The libro del edificio — your claim file, delivered in advance

The libro del edificio is required by LOE Art. 7 and — for residential buildings — by the equivalent autonomous-community regulation (Decret 67/2015 in Catalonia; Decreto 349/1999 in Andalucía, and so on). It is delivered to the comunidad de propietarios at handover, and every individual unit owner has the legal right to consult it.

A properly assembled libro del edificio contains:

• The acta de recepción de la obra (structural handover certificate).
• The proyecto de ejecución — the executed construction drawings.
• The certificado final de obra signed by the arquitecto and arquitecto técnico.
• The cédula de habitabilidad (habitability certificate).
• The certificado de eficiencia energética — see our CEE guide.
• The seguro decenal policy certificate.
• The building maintenance plan and the ITE / IEE schedule — see the technical inspection guide.
• Contact details for all professionals involved (architect, engineer, builder, developer).

When a defect appears and you need to file a seguro decenal claim, the first three documents you will need — the acta de recepción, the policy certificate, and the proyecto de ejecución (to establish that the defect is a construction failure, not a design decision) — are all in the libro del edificio. If your building's administrador cannot produce it, spend a Saturday at the comunidad AGM and put its reconstruction on the agenda. Missing libro del edificio is not an obscure defect — it is a live risk to every future claim, on every unit, for the remainder of the coverage period.

How to file a seguro decenal claim — step by step

The mechanics of a seguro decenal claim are formal and unforgiving of missed deadlines. The good news: they are also well-litigated, and the courts are consistently on the buyer's side when the paperwork is right.

Step 1: Document the defect, immediately

The moment a structural defect appears — a new crack that changes size, water intrusion at a foundation junction, a slab movement — start a defect file:

• Dated photographs from consistent angles (a smartphone photo tagged with GPS metadata is legally acceptable evidence in Spanish civil courts).
• Written observations: when did the defect first appear, in what conditions (rain, temperature change, works elsewhere in the building), how has it evolved.
• If the defect is in a communal element (foundations, structural walls, terrace waterproofing on top of a shared space), notify the presidente of the comunidad de propietarios in writing. The claim will typically be filed by the community, not the individual owner.

Step 2: Instruct a technical report (informe pericial)

You cannot file a seguro decenal claim on the strength of your own observations. You need a dictamen pericial prepared by an arquitecto técnico (or, for foundation issues, a geotécnico) that:

• Describes the defect precisely.
• Establishes that it affects elementos estructurales and compromises resistencia mecánica o estabilidad — the LOE Art. 17 language.
• Identifies the probable cause as a construction or design failure.
• Quantifies the remediation cost.

A competent informe pericial for a seguro decenal claim costs €800-€2,500 depending on complexity. In a large communal claim the comunidad pays; in an individual-unit claim you pay upfront and recover from the insurer if the claim succeeds.

Step 3: Send the comunicación fehaciente to the insurer and the developer

The claim opens formally with a burofax con acuse de recibo y certificación de contenido sent to both:

• The insurer named on the seguro decenal certificate.
• The developer (promotor).

The burofax — a state-guaranteed registered communication delivered by Correos — is the standard comunicación fehaciente under Spanish civil procedure. Email is not sufficient; a certified letter is legally weaker; a burofax is what the courts recognise. Cost: €35-€60 for a two-page communication.

The burofax should:

• Cite Ley 38/1999 (LOE), Art. 17 and Art. 19.
• Attach the informe pericial.
• Attach the seguro decenal certificate and the acta de recepción.
• State the remediation demanded and the deadline (typically 15-30 working days).
• Reserve the right to file suit in the Juzgado de Primera Instancia if the claim is not addressed.

This is the point at which most claims resolve. Insurers know the LOE-liability case law; they know that a well-prepared burofax backed by a competent informe pericial will almost certainly succeed at trial. The typical insurer response is either (a) an inspection visit by their own perito, followed by a settlement offer within 3-4 months, or (b) an explicit denial that opens the door to the next step.

Step 4: If the insurer denies — the Juzgado de Primera Instancia

If the insurer denies the claim or fails to respond within the deadline, the next step is a civil suit in the Juzgado de Primera Instancia of the partido judicial where the property is located. The action is a juicio ordinario under Art. 249 LEC.

Timeline: 18-30 months to first-instance judgment in most provinces. Cost: €4,000-€12,000 in legal fees for a €50,000-€150,000 claim, recoverable from the losing party under the condena en costas regime.

Success rate for well-prepared claims backed by an independent informe pericial is high — Tribunal Supremo case law under Art. 17-19 LOE consistently favours the buyer, and lower-court judgments follow. The insurer's defence is almost always either (a) that the defect is not structural (tier 2 or lower), (b) that the defect is outside the coverage period, or (c) that the defect was caused by owner alterations. Each of these is defeated by a strong informe pericial filed at Step 2.

The four situations where the coverage silently doesn't apply

Foreign buyers should be alert to four scenarios where the seguro decenal protection is either absent or effectively unclaimable:

1. Self-promoted homes without retroactive coverage. As above — a private individual building for their own use is exempt. On resale, the seller must either contract the policy or waive the coverage in the sale contract. Never accept an obra nueva purchase from a persona física without verifying which of these applies.
2. Pre-6-May-2000 licences. The LOE regime does not apply. Older buildings rely on the earlier — much weaker — Civil Code Art. 1591 "ruina" framework, which requires proving ruina funcional, is much harder to win, and has no mandatory insurance backing.
3. Substantial owner alterations. Load-bearing wall removal, unauthorised terrace enclosures (cerramientos), roof extensions — anything that alters the elementos estructurales the seguro decenal covers. Insurers will decline. If you are buying a resale property that has had significant works done, order a technical inspection before the escritura to establish which defects pre-date the works and which do not.
4. Developer dissolved and seguro decenal insurer insolvent. Rare, but it happens. In this case the Consorcio de Compensación de Seguros (state-owned reinsurer of last resort) may cover, but the claim mechanics are slow and coverage is capped. For a €80,000+ structural repair, this is a serious gap.

None of these situations is a reason to avoid new-build purchases in Spain — they are reasons to do the pre-signing due diligence properly.

What the seguro decenal costs the developer — and why it matters for pricing

The premium a developer pays for the seguro decenal is baked into the sale price of every new-build unit. In 2026, typical premiums run:

Building type	Typical premium	As % of construction cost
Standard mid-rise residential (5-15 units)	€5,000-€12,000 per unit	1.5-2.5%
Single-family home in a promotion	€3,500-€8,000 per unit	1.2-2.0%
High-rise (30+ units)	€8,000-€20,000 per unit	1.8-3.0%
Complex ground conditions (fill soils, high water table)	+30-50% surcharge	2.5-4.5%

That premium already sits inside the price you are quoted. The insurer requires an Organismo de Control Técnico (OCT) — an independent technical control body — to inspect the works at multiple stages and certify compliance. The OCT report is often the single most useful piece of technical evidence when a defect emerges years later, because it establishes the as-built condition of every structural element.

Ask the developer, before signing:

• Which insurer wrote the seguro decenal policy? (The three market leaders in Spain in 2026 are Mapfre, Asefa, and Musaat, with Zurich and Allianz active in the higher-value segment.)
• Which OCT signed off the works? (Applus, Bureau Veritas, TÜV Rheinland, SGS Tecnos and the local OCTs — a familiar name is a reassurance signal.)

Neither answer will change the price, but they establish quickly whether you are dealing with a professional promotion or a corner-cutting one.

Seguro decenal on resales — does it transfer?

Yes. The seguro decenal attaches to the building, not to the original buyer. When you buy a 4-year-old new-build resale, you inherit the remaining 6 years of coverage automatically — the policy is annotated in the property registry against the building, and successive owners are all beneficiaries during the coverage window.

Two consequences for resale buyers:

• You do not need to negotiate a warranty transfer. It is automatic.
• You do need to obtain the seguro decenal certificate and confirm the coverage window. Ask the seller for the libro del edificio; if they don't have it, get it from the administrador de fincas. If it cannot be located, treat this as a red flag under our red-flags framework and use it in negotiation.

For a resale in year 8 of the coverage — with 2 years of the seguro decenal remaining — the practical value of the residual coverage is limited but still real. Structural defects in year 9 of a new-build's life are uncommon but not rare, and a working policy that you can file against is worth several thousand euros of buyer negotiating leverage.

How this connects to the rest of your due diligence

The seguro decenal sits inside a broader technical-and-legal due-diligence stack that our other guides cover:

• The ITE / IEE technical building inspection becomes mandatory for buildings 45+ years old. A well-maintained libro del edificio — including the seguro decenal trail and the OCT records — makes the ITE cheaper and faster.
• The cédula de habitabilidad is a separate document — the habitability certificate — but is signed off at the same handover as the acta de recepción and lives in the same libro del edificio.
• The energy performance certificate (CEE) is another handover document. A missing CEE is a lesser gap than a missing seguro decenal but points at the same underlying issue: paperwork discipline at the developer.
• Where the defect turns out to be aluminosis or a related concrete pathology, the seguro decenal is likely to apply if the building is under 10 years old and the developer's concrete supplier is on the hook.
• Where the defect involves servidumbres or easements — a neighbour's water pipe cracking a foundation, for example — the claim can involve both the seguro decenal and a separate civil action against the neighbour.

For remote buyers and buyers using a power of attorney, all four libro del edificio documents should be reviewed by your independent lawyer before the POA-holder signs on your behalf. Adding this to your closing checklist takes twenty minutes and closes a claim risk that will otherwise sit on the property for a decade.

The bottom line

The seguro decenal is the single largest legal protection a foreign buyer of a Spanish new-build has. It is mandatory, well-litigated, and consistently paid out — but only for buyers who verify the policy exists before signing, keep the libro del edificio somewhere they can find it in year 8, know the distinction between the three warranty tiers, and act on defects with a proper informe pericial and burofax rather than an angry email to the developer.

For any new-build purchase in Spain, treat these four steps as non-negotiable:

1. Get the seguro decenal certificate before the escritura, with the policy number, insurer name, coverage limits, and acta de recepción date.
2. Confirm the policy is annotated on the building's nota simple registral.
3. Get a full copy of the libro del edificio and store it — digital and physical — with your escritura.
4. If any structural defect appears within 10 years of the acta de recepción, do not call the developer first. Instruct an arquitecto técnico for an informe pericial and file a burofax on the insurer.

For resale buyers of properties under 10 years old, the same file matters: the seguro decenal transfers automatically, but you need the paperwork to claim on it.

If you are still narrowing down which new-build or recent-resale properties match your criteria — and want to see what agents and owners have in your target zone without paying a percentage-of-price fee — you can post a request on Buvivo in about three minutes. The reverse-search model surfaces the inventory; the due-diligence checklist in this and our other guides makes sure the one you pick is one you can still defend, on paper, ten years from now.