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Rehabilitating your garage into a living room is the ideal way to expand your home. Naturally, these works are subject to specific implementation constraints. But above all, they must respect the rules of town planning in force, under penalty of heavy penalties.

Rehabilitate or transform the garage of a house

Rehabilitate or transform the garage of a house

Transform a garage into a habitable room, the benefits

Transform a garage into a living room saves a lot of space. A birth, the launch of a new activity... sometimes leads to new needs.

The garage can then serve extension to the dwelling turning into office, bedroom, playroom, bathroom, etc.

Each development is however subject to various constraints and it will be necessary to think here:

  • the thermal and sound insulation of the old garage
  • at its electrical connection
  • to its sanitary water supply
  • the provision of openings necessary for the natural lighting of the room
  • Etc.

When the extension through the garage, brings the total living area of ​​the housing to exceed 170 m², then it becomes mandatory to appeal to an architect.

If the living space does not exceed this limit, the obligation does not apply. However, it is strongly recommended to use a professional, this type of work must indeed be followed by an expert eye.

Authorizations needed to rehabilitate a garage

Transforming a garage into a living room is a project subject to certain planning rules strict. Several formalities must therefore be undertaken.

  • The plus (land use plan), regulates the "density" of constructions allowed on each land.
    A coefficient of land occupation is thus attributed to it, the COS (Coefficient of Occupation of the Soils), available in town hall. It is thus possible to check that one does not exceed the authorized living space.
    Other regulations can be imposed here, which can still be consulted in the town hall (subdivision, protected area, mandatory parking space, etc.).
  • The transformation of the garage door is considered a real facade modification. A building permit may then be required (depending on the project):
Garage areaModified facade, undamaged bearing wallModified facade, load-bearing wall with an opening
Less than 10m²No authorizationBuilding permit
Between 10m² and 20m²Prior request for workBuilding permit
More than 20 m²Building permitBuilding permit


Video Instruction: Garage framing and foundation rehab