Condominium: works and amenities in the owner's apartment
Verified 18 February 2026 - Public Service / (Prime Minister)
Works or fittings made in an apartment concern the private parts of the building, i.e. spaces reserved for the exclusive use of the owner. Consequently, these works are the responsibility of the co-owner who undertakes or causes them to be carried out. Even if the landlord is in principle free to develop his dwelling, it is vital to determine whether the works envisaged have an impact on the common areas or change the exterior appearance of the building. In this case, specific rules apply. We present you the information to know.
What applies to you ?
Works made exclusively on units
Private parts are the elements of a building reserved for the exclusive use of a co-owner. They are defined by the condominium rules, which gives a complete list.
For example, they may be non-load-bearing partitions, interior doors, windows or shutters, electrical installations, sanitary facilities, floor coverings or interior equipment (kitchen, bathroom, built-in closets).
Each co-owner freely uses and disposes of the units included in his batch. The owner can therefore, in principle, make works in his apartment without needing authorization from the general meeting of co-owners.
It exists 2 limits the freedom to make works in private units, namely:
- The destination of the building and the stipulations of the condominium by-law
- The rights of other co-owners.
Destination of the building
The destination of the building is what a building was built for. It is determined by several elements, including in particular the stipulations of condominium rules, the qualities of the building (architecture, building materials, finishes, standing, social level, use – residential, mixed, commercial…), its geographical or environmental situation.
This destination of the building is imposed on all co-owners.
The works on units must therefore conform to the purpose of the immovable. For example, if the building is exclusively for residential use, an apartment cannot be converted into a commercial space.
FYI
The realization of works affecting the destination of the immovable requires the agreement of the general meeting of co-owners. This Decision shall be adopted at theunanimity.
The condominium by-law may also contain a clause on « harmony of the building ». This clause obliges the co-owner to respect the overall aesthetics of the building. This is the case, for example, for an imposed color of shutters or the prohibition on modifying certain visible elements from the outside (windows, signs, blinds, etc.).
Rights of other co-owners
Works in an apartment must not infringe the rights of other co-owners.
Thus, the co-owner must not cause material damage to his neighbor, abnormal neighborhood disorders or a violation of the rights of the other co-owners resulting from the co-ownership regulation.
Example :
It is prohibited to:
- Deteriorate the apartments above, below or next door
- Set up claustras (separate panels) on its private terrace when it harms the sunshine and calm enjoyed by the neighboring lots
- Make an attic as a living room, causing noise nuisance for the apartment below
- Partitioning a parking space hindering the use of the neighboring site
- Replace the floor covering if it does not have sound insulation characteristics at least equal to those of the original materials, which creates noise nuisance for the apartment located below.
The realization of works infringing the rights of other co-owners requires the agreement of the general meeting of co-owners. This Decision shall be adopted at theunanimity.
What are the consequences in case of non-compliance?
Works on units, affecting the purpose of the immovable or the rights of other co-owners, must be authorized by the general meeting of co-owners. This agreement must be reached before works begin.
The co-owner may:
- Either ask the trustee of the condominium to enter this authorization in theagenda of theannual general meeting. This request is made by registered letter with acknowledgement of receipt.
- Either request the trustee to convene and hold a specific general meeting that will only concern this authorization. In this case, the co-owner shall bear all the costs relating to this meeting. This request is made by registered letter with acknowledgement of receipt.
If the works are made in the absence of such authorization (agreement not requested or not obtained), they are irregular. In this case, the trustee may oblige the co-owner to rehabilitate housing, which can lead to the demolition of what has been done.
If the attempt at an amicable settlement is unsuccessful, he can take legal action before the judicial court of the location of the immovable.
Works on units affecting common areas or the exterior of the building
The common areas are the elements of a building reserved for the use or utility of all or more co-owners. They are defined by the condominium rules, which gives a complete list.
If this is not the case, the law determines the common parts. These include:
- Floors, courtyards, parks and gardens, access roads
- Structural work of buildings (building load-bearing structure), common equipment, including parts of pipes that pass through private premises
- Chests, ducts and chimney heads
- Common Services Premises
- Passages and corridors (corridors).
When a co-owner makes works in his apartment, he may be required to intervene on common areas (for example, perforation of a load-bearing wall) or affect the exterior appearance of the building (for example, change of window).
In this case, specific rules apply.
Some works made in an apartment have an impact on the common areas of the building. Several steps must then be followed in order to be able to carry out these works.
1Check that works are not prohibited by the condominium by-law
First of all, it is necessary to ensure that the envisaged works are not prohibited by the condominium rules. If so, they cannot be carried out.
2Check that the works respect the destination of the immovable and the rights of other co-owners
Then, it is necessary to check that the desired works respect:
- The destination of the building, that is to say, what a building was built for. It is determined by several elements, including the co-ownership by-law, the qualities of the building (architecture, building materials, finishes, standing, social level, use – residential, mixed, commercial…), its geographical or environmental situation. This destination of the building is imposed on all co-owners.
- The rights of other co-owners.
Warning
Where the envisaged works concern thethermal insulation of the roof or floor, it is necessary to check that they do not affect the structure of the building, its safety and its health. Nor should they be part of the multi-annual works plan adopted by syndicate of co-owners.
3Obtain the authorization of the general meeting to carry out the works
Finally, the co-owner must obtain the agreement of the other co-owners at a general meeting. This authorization must take place before you start your works.
This decision is made at the absolute majority (so-called majority of Article 25).
However, if the works result in the appropriation or destruction of common areas, they must be permitted to double majority (so-called majority of Article 26).
To obtain this authorization, the co-owner may:
- Either ask the trustee of the condominium to enter this authorization in theagenda of theannual general meeting. This request is made by registered letter with acknowledgement of receipt, enclosing all documents relating to your draft works.
- Either request the trustee to convene and hold a specific general meeting that will only concern this authorization. In this case, he shall bear the entire costs relating to this meeting. This request is made by registered letter with acknowledgement of receipt. All documents relating to the draft works should be attached.
Where the works concern works for the accessibility of housing for disabled persons or persons with reduced mobility or works for thermal insulation of the roof or floor, it is mandatory to provide a detailed description of the works . The description shall contain:
- The nature of works
- Location (location of works in the building)
- The length and conditions of the planned works
- And the essential elements of the equipment or structure (marks, models, instructions, warranties and documents relating to use and maintenance).
The description must be accompanied by a technical response plan.
If these documents are not sent to the trustee, he will not be able to include the draft resolution on the agenda of the general meeting.
Warning
Authorization to carry out private works on the common areas may not be granted either by the union councilor by the trustee.
If the general meeting has voted against the realization of your works, the co-owner has a 2 months delay from the receipt of the minutes of that meeting to request the annulment of that refusal. The place where the building is located must then be referred to the court. This action requires the support of a lawyer.
In addition, if the works are upgrading (improving the comfort, safety or value of the condominium), the co-owner can ask the judge to be permitted to carry them out.
The works or developments envisaged in an apartment may require a modification of the exterior appearance of the building.
These are mainly works affecting openings (windows, chassis, installation of bars etc.), those linked to evacuation ducts or the installation of air conditioning.
In this case, the co-owner must obtain a authorization of the general meeting co-owners before they can hire them.
This decision is voted on at the absolute majority (called of Article 25).
To obtain this authorization, the co-owner may:
- Either ask the trustee of the condominium to enter this authorization in theagenda of theannual general meeting. This request is made by registered letter with acknowledgement of receipt, enclosing all documents relating to your draft works.
- Either request the trustee to convene and hold a specific general meeting that will only concern this authorization. In this case, he shall bear the entire costs relating to this meeting. This request is made by registered letter with acknowledgement of receipt. All documents relating to the draft works should be attached.
Warning
Works made without the authorization of the General Meeting are irregular. In this case, the syndicate of co-owners can demand the stop of the works and request the demolition of the works already carried out, including in court.
In some cases, works that have obtained the agreement of the co-owners also require a urban planning authorization. These include, for example, the works:
- Changing windows (except for identical repair or replacement works)
- Creation of opening overlooking the outside (ox-eye, window, velux...))
- Change the color of the shutters or windows
- Placing shutters or bars on windows.
Who can help me?
Find who can answer your questions in your region
For more information on this subject, you can contact Allô Service Public.
Please note: the service does not have access to users' personal files and cannot therefore provide information on their progress.
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The informants who answer you belong to the ministry in charge of housing and urban planning.
- Departmental Agency for Housing Information (Adil)
Common areas
Regulation of co-ownership
Private parts
Special AGM call
Request to add a resolution to the GA
Detailed description and technical plan of intervention
Thermal insulation works of the roof or floor
Majority vote authorization to carry out the works
Challenging a decision