Dommages-ouvrage insurance: pre-financing repairs for a decennial defect without waiting
Dommages-ouvrage insurance, mandatory for every project owner since the Spinetta law of 4 January 1978 (Article L.243-1 of the French Insurance Code), pre-finances the repair of defects covered by the decennial (10-year) warranty without waiting for a court to rule on liability. In practice, as soon as a decennial-type defect appears on a building less than ten years old, the owner reports the claim to their dommages-ouvrage insurer, who must decide whether to cover it and, if applicable, fund the works before pursuing the liable contractors and their decennial liability insurers.
In reality, this protective mechanism often runs into expert reports drawn up by the assessor appointed by the insurer, who tends to downplay the scale of the defect, dispute its decennial nature, or undervalue the cost of the repair works. Cassini Expertise, an independent building expert based in Antibes and covering the whole of the Alpes-Maritimes (06) and Var (83), supports owners at every stage: technical identification of the defect, preparation of the claim file, attendance at the joint expert assessment, and a well-argued challenge to the insurer’s report where it is undervalued.
Which defects are covered by dommages-ouvrage insurance?
The decennial warranty, and therefore the dommages-ouvrage insurance that pre-finances it, covers two categories of defects:
- Defects affecting the structural soundness of the building: through-cracks affecting the structure, foundation subsidence, defects affecting the roof frame or load-bearing elements.
- Defects making the building unfit for its intended purpose: recurring water infiltration compromising normal use of the property, extensive and lasting condensation, insulation or waterproofing defects rendering the premises uninhabitable as they stand.
Purely cosmetic defects or normal wear and tear (surface cracking, finishing issues) generally do not fall under the decennial warranty, which explains many of the coverage refusals that should be technically verified before any challenge is raised.
Common cases on the Côte d’Azur (06 and 83)
Along the coast and in the hinterland of the Alpes-Maritimes and Var, certain defects come up repeatedly in dommages-ouvrage claims:
- Structural cracking linked to clay shrink-swell movement (RGA), common on the region’s clay soils and capable of affecting the structural soundness of the building.
- Waterproofing defects on accessible terraces or flat roofs, widespread in Mediterranean-style architecture, causing infiltration into the floors below.
- Shell swimming pools with cracked or structurally compromised shells, a common decennial defect for this type of installation, particularly prevalent in the 06 and 83 departments.
Step-by-step claim declaration
The claim must be sent to the dommages-ouvrage insurer by registered letter with acknowledgement of receipt, as soon as possible after the defect is discovered. It must include:
- A copy of the dommages-ouvrage insurance policy taken out at the time of construction or renovation;
- The decennial insurance certificates of the parties involved (builder, tradespeople, project manager) concerned by the defect;
- Dated and captioned photographs of the defect(s) observed;
- A precise, dated description of when the defect appeared and how it has developed.
On receipt of a properly completed declaration, the insurer has a statutory deadline to notify its decision on coverage, before appointing an expert to assess the nature of the defect and estimate the cost of the repair works.
A common and costly mistake: a vague, incomplete or late declaration (particularly where the defect is reported long after it was discovered, or without sufficient technical description) can justify the insurer rejecting cover, on the grounds that the policyholder failed to meet their contractual obligations. Having an expert review the declaration before it is sent helps avoid this kind of avoidable rejection.
The joint dommages-ouvrage expert assessment
The insurer appoints an expert to examine the defect, determine its nature (decennial or not) and cost the repair works. This expert is structurally aligned with the economic interests of the insurer who pays them, which explains why assessments can be restrictive, exclusions questionable, and excesses sometimes wrongly applied.
During this joint expert assessment, Cassini Expertise’s role is to:
- Measure and technically document the actual scope of the defect;
- Assess the defect against the criteria of the decennial warranty (structural soundness or unfitness for purpose);
- Provide an independent cost estimate for the repair works, often higher than the insurance expert’s figure;
- Challenge, with supporting evidence, any unjustified excess or wrongly invoked forfeiture of cover.
Once the assessment is complete, the insurer has a statutory deadline of 90 days from the claim declaration to put forward a compensation offer. If no offer is made within this period, or if the offer is clearly insufficient, the policyholder can proceed with the repairs and hold the insurer liable for any losses resulting from its silence or delay, with the amounts owed increased accordingly.
Frequently asked questions
What is the deadline for declaring a claim to the dommages-ouvrage insurer?
The declaration should be made as soon as the defect is discovered, without undue delay. While the policy or the law does not set a single rigid deadline, a late declaration risks the insurer invoking the resulting loss to reduce or refuse cover. It is therefore advisable to declare the claim as soon as the first signs of the defect appear, relying on a technical opinion if there is any doubt about its decennial nature.
Is a defect that appears after the property has been sold covered by dommages-ouvrage insurance?
Yes. Dommages-ouvrage cover attaches to the building, not to the original owner: it benefits whoever owns the property when the defect appears, provided this occurs within ten years of the works being completed. The buyer of a recently built property can therefore file a decennial claim even if they were not the original project owner.
What should I do if the insurer’s compensation offer is too low?
A policyholder is never obliged to accept an offer they consider insufficient. It can be challenged by relying on an independent expert’s counter-estimate demonstrating that the actual cost of the repair works exceeds the insurer’s assessment. This kind of technically documented challenge often results in a revised offer without the need for legal proceedings.
Who pays the expert appointed by the insurer?
The expert acting on behalf of the dommages-ouvrage insurer is paid by that insurer, which is not without consequence for the outcome of the assessment. Bringing in your own independent expert for the joint assessment helps rebalance the technical discussion and secure an objective evaluation of the defect and the works required.
For a defect linked to drought or ground movement, see our dedicated page on RGA and natural disaster expert assessment in the 06 and 83. If an expert report seems questionable, discover our independent building counter-assessment in the 06 and 83. For a free quote and support with your dommages-ouvrage claim declaration, contact Cassini Expertise on 04 22 46 06 04.
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📅 Mis à jour le 25/09/2026 — Cassini Expertise, expert bâtiment indépendant (06·83·13·40).