10-Year and 30-Year Warranties: What Your Humidity Insurance (Really) Covers
The 10-year warranty (garantie décennale), provided by the Civil Code, holds a builder liable for ten years after the acceptance of work for damages that compromise the solidity of the structure or render it unfit for its intended purpose. A humidity problem is only covered if it results from a design or execution defect, and not from a lack of maintenance or normal wear and tear.
Some specialized companies offer a complementary 30-year contractual warranty specific to their waterproofing services (notably tanking), which does not have the same legal nature as the mandatory 10-year warranty. This article is not intended to constitute personalized legal advice.
10-Year Warranty: Legal Framework Overview
The 10-year warranty is based on Article 1792 of the Civil Code, which establishes a presumption of liability for the builder for damages, even those resulting from a soil defect, that compromise the solidity of the structure or render it unfit for its purpose. It applies for ten years from the acceptance of the work, whether it is new construction or significant renovation.
The term \"builder\" is understood broadly in case law: architect, contractor, project manager, but also any technician linked to the client by a contract for work — including specialized companies working on a technical lot such as waterproofing or drainage.
Essential point: the 10-year warranty does not cover all disorders, but only those reaching a certain threshold of severity (damage to structural integrity or unfitness for purpose). An aesthetic inconvenience without structural consequences falls under the one-year warranty of perfect completion (garantie de parfait achèvement) or general common law remedies.
Is Humidity Always Covered by the 10-Year Warranty?
No, and this is the most misunderstood point by property owners. For a humidity problem to fall under the 10-year warranty, one must demonstrate a link to a design or execution defect in the work completed within the previous ten years.
Cases That May Fall Under the 10-Year Warranty (Subject to Expert Assessment)
- Rising damp appearing shortly after the construction of a new building, revealing the absence or failure of a damp-proof course.
- A basement infiltration after professional tanking, if the waterproofing proves defective within the first few years.
- A defect in peripheral drainage delivered with new construction, leading to recurring cellar infiltrations.
Cases Generally Not Covered by the 10-Year Warranty
- Rising damp in an old building, unrelated to recent work.
- Escalation of humidity due to lack of maintenance (clogged gutters, vegetation against foundations).
- Normal wear and tear of an old treatment reaching the end of its lifespan, without initial execution defects.
The 30-Year Warranty Specific to Tanking and Waterproofing
Distinct from the legal 10-year warranty, a 30-year warranty is frequently offered by companies specialized in humidity treatment, particularly for tanking and waterproofing services. This is a contractual commitment by the company, often backed by specific professional civil liability insurance, but it does not have the same legal basis as the 10-year warranty provided by the Civil Code.
In practice, the company contractually commits to intervening in the event of failure of its treatment for thirty years, regardless of whether the disorder falls under the legal 10-year warranty. It is an important commercial argument, but one that deserves detailed verification: what are the conditions of application, what are the exclusions, and what is the financial solidity of the company to honor this commitment (ideally via dedicated insurance rather than a simple promise).
Damage-to-Work Insurance: Role and Coordination
Damage-to-work insurance (assurance dommage-ouvrage) is taken out by the client before starting construction or major renovation work. Its main benefit: it allows for rapid compensation for disorders falling under the 10-year warranty, without waiting for a court decision to determine liability. The damage-to-work insurer first compensates the client and then seeks reimbursement from the liable parties and their decennial insurers. For a humidity problem discovered after work covered by damage-to-work insurance, this insurance can significantly speed up claim processing.
Practical Cases
Rising damp after new construction. If a building delivered less than ten years ago shows rising damp, the hypothesis of an execution defect (absence of a waterproof barrier, capillary bridge created by poorly designed exterior paving) should be examined as a priority, with technical expertise to establish causality.
Infiltration after recent tanking. If tanking performed by a specialized company fails within ten years, the company's 10-year warranty can potentially be triggered, in addition to any offered 30-year contractual warranty.
Peripheral drainage malfunction. Poorly sized or connected drainage, delivered with a recent construction and proving insufficient, may fall under the 10-year warranty if the design defect is demonstrated by an expert report.
How to Activate a Warranty
- Declare the loss quickly, by registered letter with acknowledgment of receipt, to the company and, if applicable, the damage-to-work insurer.
- Respect the limitation periods: the 10-year warranty can only be invoked within ten years following the acceptance of the work.
- Arrange a contradictory expert assessment bringing together the owner, the company involved, and potentially an insurance expert.
- Keep all evidence: initial quotes and invoices, dated photos of the disorders, diagnostic reports, and correspondence exchanged.
What is Never Covered
- Lack of maintenance: clogged gutters, untrimmed vegetation, lack of maintenance of existing drainage.
- Absence of appropriate ventilation installed by the occupant, which causes condensation.
- Normal wear and tear of a treatment reaching the end of its life after several decades.
- Damage linked to work performed by the owner or by an uninsured company.
Verify a Provider's Warranty Before Signing
- The existence of professional civil liability insurance and a valid 10-year warranty (request a certificate).
- The precise conditions of any offered 30-year contractual warranty (duration, exclusions, terms).
- The solidity and age of the company: a thirty-year commitment only has real value if the company is able to honor it.
FAQ
Does the 10-year warranty apply to a simple rising damp treatment performed on an old building?
Yes, insofar as this treatment itself constitutes work carried out by a professional: if the resin injection fails within ten years of its completion, the 10-year warranty of the company that performed the work can potentially apply, regardless of the age of the building itself.
What happens if the company that performed the work has closed?
This is one of the major benefits of mandatory damage-to-work insurance and the 10-year warranty: in theory, the company's decennial insurer remains committed even if the company has ceased activity, provided that the insurance certificate was properly issued at the time of the work.
Is a company's 30-year warranty equivalent to a legal warranty?
No, it remains a contractual commitment specific to the company, distinct from the legal 10-year warranty provided by the Civil Code. Its practical value depends on the financial stability and insurance of the company offering it.
Can a 10-year warranty claim be initiated without a prior expert report?
A declaration can be made without waiting, but a contradictory expert assessment is almost always necessary to establish the link between the observed disorder and a design or execution defect in the work, which is an essential condition for triggering the warranty.
Does the 10-year warranty cover damage to movable property stored in a cellar?
Generally no: the 10-year warranty applies to the structure itself (solidity, unfitness for purpose), not to movable property, which is more a matter for the owner's home insurance or the company's civil liability in the event of proven fault.
How much time is there to act after discovering a disorder covered by the 10-year warranty?
Legal action must be initiated before the expiration of the ten-year period starting from the acceptance of the work; once this period has passed, the legal 10-year warranty can no longer be invoked, hence the importance of acting quickly as soon as a suspicious disorder is discovered.
This article presents a general framework and does not replace personalized legal consultation. ZeroHumi conducts technical diagnostics to objectify the origin of a disorder, which is useful prior to a warranty claim. Request a diagnosis →
Sources et références
Cet article s'appuie sur des sources officielles et vérifiées pour garantir la fiabilité des informations.
- [1]Article 1792 of the Civil Code— Légifrance
- [2]Construction Insurance and Decennial Liability— Service Public
- [3]French Insurance Federation— France Assureurs
Rédaction ZeroHumi
Équipe éditoriale ZeroHumi
Documentation technique vérifiée à partir des sources citées (ADEME, ANSES, OMS, CSTB, CEREMA)