The ten-year warranty protects homeowners against serious defects affecting the structural integrity of the building or rendering it unfit for its intended purpose. Contractors systematically refuse to cover aesthetic defects, equipment not incorporated into the structure, damage attributable to lack of maintenance, and apparent defects not reported at the time of work acceptance. These exclusions give rise to numerous disputes between project owners and professionals. Understanding the precise limits of this warranty will allow you to anticipate refusals and better defend your rights.
Aesthetic defects: the leading cause of rejection
Builders regularly refuse to provide coverage when the defects observed only concern the visual appearance of the building. The ten-year warranty only covers damage that compromises the structural integrity of the work or renders it unfit for its intended purpose, which excludes mere aesthetic imperfections.
A superficial crack in exterior plaster, a colour difference between two batches of tiles, or visible brush marks on a painted surface do not fall under this warranty. These defects may admittedly diminish the appearance of your property, but they do not affect its primary function or structural durability.
Case law does, however, distinguish between purely aesthetic cracks and those that reveal an underlying structural problem. A progressive through-crack, even if it initially appears aesthetic in nature, may indicate differential foundation settlement or a lack of structural ties. In such cases, technical expert assessment becomes essential to properly characterise the damage.
Detachable equipment: a common exclusion
Insurers and builders systematically reject claims relating to elements considered separable from the building structure. This notion of incorporation into the structural work constitutes a determining criterion for the application of the ten-year warranty.
Equipment generally excluded from warranty
- Electric roller shutters: mechanism and motor not built-in
- Mobile or split air conditioners: reversible installation
- Removable fitted kitchens: non-sealed units
- External blinds: removable fixing
- Motorised gates: equipment independent of the structure
- Alarm systems: wiring not integrated into the building
The distinction between incorporated and dissociable equipment can sometimes be complex. A heat pump integrated into the central heating system and requiring masonry work for its installation may be considered an indissociable piece of equipment. Conversely, an electric radiator simply mounted on the wall remains dissociable equipment, covered only by the two-year guarantee of proper functioning.
Apparent defects not reserved at reception
The minutes of acceptance of works mark a crucial moment in the life of a construction site. Any visible defect detectable by a normally diligent project owner must be reported at this formal stage, failing which any subsequent claim for coverage may be refused.
Builders regularly invoke this rule to escape their obligations. A visible crack on a wall, a misalignment of the joinery, poorly laid tiling or a reversed terrace slope all constitute apparent defects. If you accept the handover without raising reservations about these points, you permanently lose the possibility of obtaining redress under the ten-year warranty.
Acceptance pronounced without reservation purges apparent defects and prevents any subsequent action by the employer, even if these defects later worsen and compromise the structural integrity of the work.
This rule has one important exception, however: if a visible defect evolves and subsequently reveals a disorder of a decennial nature, the warranty may be invoked. The evolution of the damage then transforms its legal classification.
Damages related to lack of maintenance
Decennial insurers systematically refuse claims when the damage results from a lack of regular maintenance of the structure. The owner is indeed under an obligation to carry out normal upkeep of their property, and decennial liability insurance cannot compensate for negligence in routine maintenance.
The clogging of an uncleaned VMC causing condensation, the blockage of gutters leading to water infiltration, or the deterioration of an unmaintained terrace waterproofing membrane are typical examples of refusals. The boundary between construction defects and maintenance failures nevertheless gives rise to numerous disputes, as builders sometimes attempt to attribute to poor maintenance those problems that actually stem from initial faulty workmanship.
Table of responsibilities according to the origin of the damage
| Type of damage | Liability | Applicable warranty |
| Infiltration due to waterproofing design defect | Builder | Ten-year warranty |
| Infiltration due to uncleaned blocked gutter | Owner | No warranty |
| Progressive structural crack | Builder | Ten-year warranty |
| Deterioration due to absence of rendering work for 20 years | Owner | No warranty |
| Boiler breakdown due to lack of annual maintenance | Owner | No warranty |
| VMC malfunction due to sizing defect | Builder | Ten-year warranty if uninhabitable |
Damages caused by a third party or an external event
The decennial guarantee covers exclusively construction defects attributable to the professionals involved on the site. Any damage resulting from the intervention of a third party or an external event therefore falls outside its scope of application.
Builders therefore refuse to cover damage resulting from subsequent poor workmanship by another professional, damage caused by a disaster (fire, water damage, storm), or disorders arising from alterations to the structure made by the owner. A crack that appears after a load-bearing wall is demolished by the project owner cannot engage the ten-year liability of the original builder.
The difficulty sometimes lies in establishing the causal link. Water damage can reveal a pre-existing defect in the waterproofing, just as subsequent work can bring to light an initial design flaw. Contradictory expert assessment then becomes essential to apportion responsibilities.
Damages occurring outside the ten-year period
The starting point of the ten-year period corresponds to the date of acceptance of the works, with or without reservations. Any defect that appears after the expiry of this ten-year period can no longer be covered under the decennial guarantee, even if it unquestionably results from a construction defect.
Insurers apply this ground for refusal strictly. A crack that appears ten years and one month after handover, even if it reveals a major foundation defect, falls outside the coverage. This rule may seem harsh, but it serves the need for legal certainty and allows builders to know precisely the temporal extent of their liability.
Two nuances temper this strictness, however: on the one hand, the defect must manifest itself within the ten-year period, but the liability action may be brought within the year following that manifestation. On the other hand, in the event of a disputed tacit acceptance or fraudulent concealment of a defect by the contractor, the courts may recharacterise the starting point of the limitation period.
Non-conformities without decennial severity
Many project owners confuse non-conformity with the contract and damage of a decennial nature. Decennial liability does not cover every contractual breach, but only damage that affects the structural integrity of the work or renders it unfit for its intended purpose.
A living area a few square meters smaller than specified in the contract, the installation of a different faucet model from the one ordered, or the use of a slightly different paint shade all constitute contractual non-conformities. These shortcomings may justify a claim for contractual liability, a request for a price reduction or rectification, but they do not give rise to the ten-year warranty.
- Installation of equipment from a different brand but of equivalent quality
- Minor plan modifications with no functional impact
- Finishes of an acceptable quality level but below expectations
Case law considers that a work is unfit for its intended purpose when it cannot fulfil the function for which it was designed, or when it presents defects so serious that they prevent normal use. A mere inconvenience or slightly degraded performance is generally not sufficient.
Disorders covered by other guarantees
The construction warranty system establishes a hierarchy among several protection mechanisms. Certain defects fall outside the ten-year warranty because they are covered by other specific warranties, notably the perfect completion warranty or the two-year warranty of proper functioning.
The guarantee of perfect completion, lasting one year from the date of acceptance, covers all reported defects, whether they are of a ten-year nature or not. Contractors often prefer to use this guarantee for claims arising within the first year, as it allows them to avoid making a declaration under the ten-year insurance policy.
The two-year guarantee covers equipment that can be separated from the building structure and requires it to function properly for two years. A malfunction of roller shutters, plumbing fixtures, or radiators falls under this specific guarantee, and not under the ten-year guarantee.
Meeting deadlines and accurately classifying the defect in legal terms are essential to the success of any claim. Misdirecting a claim between the various warranties can permanently compromise your rights.
How to effectively challenge a refusal of coverage
When faced with a refusal from the insurer or the builder, several options are available to challenge the decision and assert your rights. The first step is to request an independent technical assessment that will objectively establish the nature of the defect, its origin, and its classification under the ten-year warranty.
Amicable or judicial expert assessment makes it possible to move beyond the subjective assessments of the parties. A qualified building expert will analyse the plans, the applicable DTUs, industry standards and the progression of defects to determine whether they genuinely fall under the decennial guarantee. Their report constitutes a decisive piece of evidence in the event of litigation.
If the expert report confirms the ten-year nature of the defect, you can initiate a formal notice procedure and, if necessary, legal action. The competent court will vary depending on whether you are invoking the contractor’s contractual liability or the decennial insurer’s guarantee. In all cases, preserving evidence and building a documented file from the moment the defects appear will considerably increase your chances of success.
Effectively protect your rights from the construction stage
The best defense against coverage refusals is to adopt a vigilant stance throughout the construction process. The careful drafting of the acceptance report, with detailed recording of all noted reservations, constitutes a fundamental legal act. Do not hesitate to seek professional assistance during this crucial step.
The systematic preservation of all documents (plans, specifications, contracts, invoices, progress photographs) greatly facilitates the establishment of proof in the event of a dispute. If there is any doubt about the classification of a defect, always opt for a prompt formal declaration rather than a wait-and-see approach, as deadlines rarely work in the owner’s favour. A precise knowledge of the exclusions from the ten-year builder’s warranty will allow you to anticipate the defence strategies of contractors and adapt your arguments accordingly.