Which works require Dommage Ouvrage insurance?
New build, extension, renovation, insulation, veranda: for which works is Dommage Ouvrage insurance mandatory? A clear list and practical examples.
Not every project requires Dommage Ouvrage (structural damage) insurance. But as soon as work touches the structure or components that are inseparable from the building, the question comes up immediately. Here is how to clearly determine whether your works fall under this obligation.
The principle: anything covered by the décennale
The golden rule for identifying a DO obligation is simple: any work that triggers a builder's ten-year structural warranty requires Dommage Ouvrage insurance. It is Article 1792 of the Code civil (French Civil Code) that defines the scope of the décennale, and DO insurance follows that same scope.
In practical terms, the décennale covers any damage that:
- compromises the soundness of the structure;
- renders the property unfit for its intended purpose;
- affects the soundness of equipment components inseparable from the building.
If your works could, in the event of a defect, cause any of these outcomes, they fall under the décennale — and therefore under DO insurance.
A clear list of the works concerned
New construction
Without question, all new construction projects require DO insurance:
- single-family homes;
- multi-unit residential buildings;
- commercial or industrial buildings;
- substantial masonry outbuildings (attached garage, habitable annexe).
Extensions and adding a storey
Any increase in floor area or volume is concerned:
- side extensions in masonry, timber frame or steel frame;
- adding a storey (building up);
- converting an attic with the creation of a load-bearing floor;
- masonry veranda (with a slab and structure integrated into the building).
Major renovation
This is often where the most questions arise. The following are concerned:
- re-roofing or roof framework work;
- underpinning or repairing foundations;
- altering load-bearing walls;
- renovating a load-bearing floor;
- creating or removing structural openings.
Waterproofing and façades
- flat-roof (terrace roof) waterproofing;
- external wall insulation (ITE) over a significant part of the building;
- structural render work incorporating insulation;
- basement or foundation waterproofing;
- cladding integrated into the building envelope system.
Inseparable equipment
Certain systems, because they are built into the structure, fall under the décennale:
- underfloor heating embedded in the slab;
- central heating with an integrated circuit;
- a heat pump connected to underfloor heating;
- an integrated dual-flow mechanical ventilation system;
- solar components integrated into the roof (rather than surface-mounted on top).
A list of works that do NOT require DO insurance
Conversely, some works fall outside the scope of the décennale, and therefore require no mandatory DO insurance:
- painting, wallpaper, decorative render;
- unfixed floor coverings (floating parquet, carpet);
- replacing a kitchen or bathroom without any structural changes;
- built-in furniture (cupboards, fitted wardrobes);
- fitting roller shutters or external blinds;
- replacing windows without altering the opening;
- interior joinery;
- removable equipment: electric radiators, split air conditioners, a surface-mounted water heater.
Borderline cases to examine carefully
Some situations warrant a case-by-case analysis.
Replacing windows
- If you replace like for like without altering the reveal: no mandatory décennale in principle.
- If you enlarge the opening or alter the lintel: this is structural work, and DO insurance is required.
Insulation
- Standard interior insulation (glass wool, plasterboard): generally no DO insurance required.
- External wall insulation (ITE): DO insurance is mandatory as soon as it forms a system integrated into the building.
Swimming pools
- In-ground masonry pool: décennale and DO insurance both mandatory.
- Above-ground, dismountable pool: neither required.
- Semi-in-ground kit pool: a disputed case — assess whether it is "inseparable".
Verandas
- Masonry veranda with a slab, foundations and an integrated roof: DO insurance is mandatory.
- Dismountable aluminium veranda fitted onto an existing terrace: no DO insurance.
The key role of the technical specification
When you request a quote for Dommage Ouvrage insurance, the insurer examines in detail:
- the exhaustive list of planned works;
- the technical trades (lots) involved;
- the contractors selected and their insurance;
- the plans and technical specifications (CCTP) for the project.
The more precise the specification, the more accurately the insurer can delimit the scope covered and avoid grey areas in the event of a claim. Work left out of the specification risks not being covered.
What about co-ownership properties?
Co-owned buildings (copropriétés) are also subject to the obligation as soon as works go beyond routine maintenance:
- render work including insulation;
- re-roofing;
- renovation of structural common areas;
- installation of a lift;
- creating an extension on common areas.
In that case DO insurance is taken out by the owners' association (syndicat des copropriétaires), represented by the managing agent (syndic).
In summary
- DO insurance is mandatory for all works covered by the ten-year structural warranty.
- Concerned: new construction, extensions, adding a storey, major renovation, waterproofing, external insulation, inseparable equipment.
- Not concerned: painting, unfixed coverings, removable equipment, interior joinery.
- Borderline cases (windows, insulation, verandas, pools) must be analysed individually.
- A precise technical specification is essential to proper cover.
Need some guidance?
Determining precisely whether your project falls under DO insurance and calibrating the right cover requires technical expertise. Our team of brokers will support you in choosing your Dommage Ouvrage insurance by analysing each trade in your works. Request a personalised quote or get in touch with an adviser.
