Decennial liability and party wall: when the risk of collapse is not a certainty

Imagine the scene: you are the owner of a pretty villa in Roquebrune-Cap-Martin, with a breathtaking view of the Mediterranean. Your neighbour, owner of the adjoining land, decides to raise the wall separating your two properties. The work is entrusted to a craftsman, everything seems in order. But a few months later, cracks appear, the wall begins to lean dangerously. You worry: what if it collapses? Who will pay for the repairs? This situation, unfortunately common, raises a crucial legal question: can a mere risk of collapse, not yet realised, be covered by the builders' decennial liability?

Decennial liability is compulsory insurance for building professionals covering, for ten years after the handover of the works, damage that compromises the solidity of the structure or renders it unfit for its purpose. But the damage must be actual, not merely potential. This is where the decision of the Court of Cassation of 23 October 2013 (No. 12-24.201) provides essential clarification.

In this case, the High Court overturned a court of appeal which had recognised that the risk of collapse of a party wall constituted an impairment to the solidity of the structure falling within the decennial liability, but had refused to apply this liability on the ground that it could not be proved that the collapse would occur within the ten-year period. For the Court of Cassation, this is contradictory: if the risk is established, the liability applies, even if the collapse is not certain within ten years. A decision with concrete consequences for owners and professionals.

The facts: a story like many that happen every day

To understand the issue, we must go back to the facts. In 2006, two neighbours, whom we will call Mr X and Mrs Y, owners of adjoining plots in Beausoleil, in the Alpes-Maritimes, decided to modify the party wall separating their lands. They agreed to raise it by four "cairons" (hollow bricks) and to build a new connecting wall, which they described as party, over a length of 19.10 metres. The work was carried out by a contractor, Mr Z, who acted as builder.

But quickly, defects appeared: the wall had cracks, it leaned, and an expert appointed by the insurance company concluded that there was a risk of collapse. The owners sued the contractor before the tribunal de grande instance of Nice, relying on decennial liability. The contractor argued that the mere risk of collapse, not realised, did not constitute damage entitling them to decennial liability. The tribunal ruled in his favour, and the court of appeal of Aix-en-Provence upheld the judgment.

But the owners did not give up and appealed to the Court of Cassation. The Court of Cassation quashed the appeal judgment on the ground that the court of appeal had failed to draw the legal consequences from its own findings. Indeed, it had held that the risk of collapse constituted an impairment to the solidity of the structure, which falls within decennial liability. But it then noted that it could not be specified whether the loss of the structure would occur within the ten-year period. For the Court of Cassation, this is contradictory: once the risk of collapse is established and it compromises the solidity of the structure, decennial liability is owed, regardless of whether the collapse actually occurs within ten years.

The reasoning of the court — broken down

The heart of the dispute lies in the interpretation of Article 1792 of the Civil Code, which defines decennial liability. This article provides that "any builder of a structure is strictly liable to the owner or purchaser of the structure for damage, even resulting from a defect in the ground, which compromises the solidity of the structure or, by affecting it in one of its constituent elements or one of its equipment elements, renders it unfit for its purpose." In other words, the builder is automatically liable, without needing to prove fault, for damage that impairs the solidity or purpose of the structure, for ten years after the handover of the works.

But what does "compromises the solidity" mean? Does the collapse have to have already occurred, or is it sufficient that it is probable? The lower courts (tribunal and court of appeal) had considered that a mere risk, even serious, was not enough as long as the collapse was not certain within the ten-year period. The Court of Cassation says no: if the risk is established, the liability applies. In other words, it is not necessary to wait for the wall to collapse to hold the builder liable. What matters is that the wall, in its current state, presents such a danger that its solidity is compromised, even if the collapse might occur after the ten-year period.

This reasoning is part of a jurisprudence protective of owners. The Court of Cassation considers that the purpose of decennial liability is to protect the owner against serious defects affecting the structure, not to wait for them to materialise before providing compensation. This is a notable evolution from a more restrictive approach that required certain and current damage. However, this does not mean that all aesthetic or minor defects are covered. The damage must be of a nature to compromise solidity or render the structure unfit for its purpose. What few people know is that case law has clarified that a mere risk of collapse, if established by an expert, constitutes an impairment to solidity.

The parties' arguments were classic: the owners relied on decennial liability, the contractor argued that the damage was not certain. The court of appeal had followed the contractor, but the Court of Cassation restored the balance in favour of the owners. undefined, I have come across cases where owners hesitated to act because the wall had not yet collapsed. This decision gives them a solid legal weapon: as soon as an expert identifies a serious risk, they can trigger decennial liability.

What this means for you — concretely

Concretely, this decision has important practical implications for several reader profiles.

For the landlord owner: if you own a rental property in Nice or Grasse, and a party wall shows signs of weakness (cracks, leaning), you can hold the builder liable on the basis of decennial liability, even if the wall has not collapsed. You will need to demonstrate through an expert report that the risk of collapse is real. The cost of repairs can be high: expect between €5,000 and €15,000 for underpinning a 20-metre wall. Decennial liability allows you to obtain compensation without having to prove the builder's fault. However, the ten-year period runs from the handover of the works. If you bought the building after handover, you benefit from the liability until its expiry.

For the tenant: you are not directly a beneficiary of decennial liability, as it only benefits the project owner (owner) or subsequent purchasers. But if a threatening wall collapses, you can report the danger to the owner. The owner has a duty of safety and maintenance, and if they do not act, you can apply to the urgent applications judge for emergency works. In Beausoleil, for example, a tenant whose courtyard wall threatens to collapse can request a judicial expert report and an interim payment for works.

For the purchaser: when buying a property, check the condition of the party wall. If defects exist, you can ask the seller to justify the existence of decennial liability or building damage insurance. In the case of a hidden defect, you can take action against the seller, but decennial liability is more protective as it directly engages the builder. If you buy a co-ownership property, the managing agent must ensure the maintenance of common parts, including party walls. In the event of damage, it is the co-ownership association that acts against the builder.

For the co-owner: if the party wall is a common part (which is often the case), co-owners are jointly liable for repair costs. But they can seek recourse against the builder on the basis of decennial liability. It is therefore essential that the managing agent arranges an expert report as soon as the first signs of disorder appear. In a case I handled in Nice, a retaining wall between two co-ownerships threatened to collapse. The expert concluded a serious risk, and the managing agent obtained compensation of €80,000 under decennial liability, avoiding a heavy burden on the co-owners.

If you are in this situation, you must act quickly. The limitation period for decennial liability is ten years from handover, but it can be interrupted by a court summons. Do not delay: as soon as you notice a risk, consult an expert and a lawyer lawyer.

Four tips to avoid this type of dispute

• Have a soil study carried out before any work to raise a party wall. An improperly founded wall can become unstable. In Roquebrune-Cap-Martin, the land is often sloping, requiring suitable foundations. The cost of a geotechnical study (around €1,500) is negligible compared to the risk of collapse.
• Require your builder to have valid decennial liability insurance. Check the insurance certificate before work begins. In the event of damage, you can directly claim against the insurer. Without this insurance, you may have to advance repair costs.
• Sign a written and detailed construction contract. Mention the materials, techniques, and applicable standards (DTU). In case of dispute, this document will serve as proof. Avoid informal agreements without writing: they are a source of litigation.
• Have the defects recorded by an expert at the first signs. Do not wait for the situation to worsen. An amicable expert report may suffice to initiate proceedings, but a judicial expert report is often necessary to obtain compensation. The cost of the expert report (€2,000 to €5,000) can be advanced by legal protection insurance.

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Further reading: related case law and developments

This decision is part of a jurisprudential trend favourable to owners. Already, in a judgment of 17 January 2006 (No. 04-16.516), the Court of Cassation had ruled that decennial liability covers damage that compromises the solidity of the structure, even if it only manifests after the expiry of the ten-year period, provided it originates from a defect existing before handover. The 2013 decision goes further by admitting a mere risk.

But this solution is not absolute. In a more recent judgment of 12 July 2018 (No. 17-17.688), the Court of Cassation clarified that the risk of collapse must be certain and not hypothetical. In other words, a mere fear is not enough: a solid technical diagnosis is required. Courts will therefore assess the reliability of the expert report. undefined that a non-adversarial or too vague expert report may be disregarded.

What this case law means for the future: builders must be more vigilant about the quality of their work, as they can be held liable before the damage even materialises. For owners, this is enhanced protection, but it requires them to react quickly as soon as the first signs appear.

Key points to remember

Practical FAQ:

1. Is the mere risk of collapse covered by decennial liability? Yes, if the risk is established by an expert report, even if the collapse is not certain within ten years.
2. Who can invoke decennial liability? The project owner (owner who had the construction done) and subsequent purchasers of the property. Tenants cannot invoke it directly.
3. What is the time limit to act? Ten years from the handover of the works. After this period, you can no longer act on this basis, but you may possibly invoke the warranty for hidden defects (two-year period from discovery of the defect).
4. What should I do if my wall has cracks? Immediately have the defects recorded by an expert (amicable or judicial). Consult a lawyer lawyer to initiate proceedings against the builder or their insurer.
5. Can I obtain compensation without waiting for the collapse? Yes, the 2013 decision confirms this. You can claim in court the cost of remedial works, even if the wall is still standing.

Are you in a similar situation? A first 30-minute consultation with Maître Zakine (€45) can save you months of proceedings — and often much more. Book an appointment →