Condominium: works and developments in the apartment of the owner occupant

Verified 16 November 2023 - Legal and Administrative Information Directorate (Prime Minister)

Do you want to carry out work in your apartment? We tell you what rules to follow depending on whether the private works have an impact on the common areas.

Private works are those not covered by the joint owners' union but are financed by the co-owner who carries them out or causes them to be executed. They concern private parts, those reserved for the exclusive use of the co-owner. However, this work may have an impact on the common areas of the building.

Impact-free work

Each co-owner has the private parts included in their lot ; he freely uses and enjoys the private parts.

The following are considered as private parts: windows, doors, shutters, floor coverings, unless otherwise provided by the condominium rules.

You are therefore free, in principle, to carry out work in your apartment without needing authorization from the general meeting of the co-owners to carry out this work.

The freedom to carry out work in your private areas knows 3 boundaries :

  • The destination of the building
  • The exterior appearance of the building
  • The rights of the other co-owners

Destination of the building

The use of the private parts of your accommodation must be in accordance with the destination of the building fixed by the co-ownership rules.

The architecture, the location of the property, the existing services or equipment make it possible, in particular, to define the destination of the building.

For example, mount a partition in your apartment to divide it into 2 lots for tourist rental may be prohibited if this is not in accordance with the destination of the building.

You must therefore verify before carrying out your work that it will not be contrary to the destination of the building.

The execution of works affecting the destination of the building requires a vote in the general meeting of the co-owners adopted unanimously.

Exterior of the building

When the work affects the exterior appearance of the building (for example, closing a balcony, creating a window), you must obtain authorization from the general meeting of the co-owners before you can engage them.

The required majority will depend on the nature of the work.

In general, an absolute majority vote is of Article 25 is required. However, a double majority vote, called Article 26 may be required.

The absolute majority (said majority of article 25) corresponds to the majority of the votes of all the co-owners of the building (present, represented and absent).

If the decision has received at least of the votes, it may be the subject of a 2nd simple majority vote on article 24 (majority of votes of co-owners present, represented or voting by mail).

The double majority (said majority of article 26) is the majority of the co-owners of the building representing at least 2/3 of the votes of the co-owners.

Example :

In a co-ownership of 10 co-owners (representing a total of 1000 thousandths), a decision is adopted if 6 co-owners holding 700 thousandths, or more than 2/3 of all the tenths (2/3 of 1000 = 667), validate this decision.

If this majority is difficult to obtain, it is possible to make a 2nd simpler majority voting. That's what we call the double majority. So that this 2nd Voting is possible, the resolution must have the approval of half of the co-owners representing at least of the votes of all the co-owners. The same assembly will then be able to vote on the resolution by a majority of the votes of all the co-owners, that is to say by a majority called Article 25 (easier to obtain).

In some cases, work that has been agreed to by the co-owners also requires a city planning authorization.

Examples of such work include:

  • Changing windows (except for identical repair or replacement work)
  • Creation of opening overlooking the outside (bull's eye, window, Velux...)
  • Change the color of panes or windows
  • Placing shutters or bars on windows

Rights of other co-owners

The exclusive use of the private parts is carried out freely on condition that the rights of the other co-owners are not affected.

For example, the work must not create damage, neighborhood disorder...

To prevent this, the co-ownership regulation may prohibit certain actions. You must therefore check the co-ownership rules before carrying out your work.

The carrying out of works affecting the rights of other co-owners requires a vote at the general meeting of the co-owners adopted unanimously.

Work done in the absence of a vote when such a vote is necessary is therefore illegal.

Co-owners who are aware of it can inform the condominium trustee.

The trustee will ask the co-owner to rehabilitate the housing.

In the event of inaction by the co-owner, the trustee must attempt a settlement before to appeal to the court of law of the place where the immovable property is situated. To do so, he must call on a conciliator of justice (free of charge) or mediator (paid approach) or to a participatory procedure (paid approach with recourse to a lawyer).

In the event of failure, the trustee will be able to appeal to the court.

Please note

The appeal to the court of justice can be exercised for 10 years. After this period, it is no longer possible to contest the illegal works.

Impact work

Private works can have an impact on common areas.

Inside your accommodation, the areas considered as common areas are as follows:

  • Major work of the building (supporting structure of the building)
  • Soil
  • Parts of pipes that run through housings
  • Chests, ducts and chimney heads

For example, when you carry out work that has an impact on the building's district heating system, you are harming the common areas.

Therefore, in order to carry out this type of work, you must obtain the agreement of the other co-owners at the general meeting.

The required majority will depend on the nature of the work.

In general, an absolute majority vote is of Article 25 is required (this is the case, for example, when lowering a wall or creating a door). On the other hand, in the case of appropriation or destruction of a common part, a double majority vote called Article 26 is required.

The absolute majority (said majority of article 25) corresponds to the majority of the votes of all the co-owners of the building (present, represented and absent).

If the decision has received at least of the votes, it may be the subject of a 2nd simple majority vote on article 24 (majority of votes of co-owners present, represented or voting by mail).

The double majority (said majority of article 26) is the majority of the co-owners of the building representing at least 2/3 of the votes of the co-owners.

Example :

In a co-ownership of 10 co-owners (representing a total of 1000 thousandths), a decision is adopted if 6 co-owners holding 700 thousandths, or more than 2/3 of all the tenths (2/3 of 1000 = 667), validate this decision.

If this majority is difficult to obtain, it is possible to make a 2nd simpler majority voting. That's what we call the double majority. So that this 2nd Voting is possible, the resolution must have the approval of half of the co-owners representing at least of the votes of all the co-owners. The same assembly will then be able to vote on the resolution by a majority of the votes of all the co-owners, that is to say by a majority called Article 25 (easier to obtain).

The work done in the absence of a vote is therefore illegal.

Co-owners who are aware of it can inform the condominium trustee.

The trustee will ask the co-owner to rehabilitate the housing.

In the event of inaction by the co-owner, the trustee must attempt a settlement before to appeal to the court of law of the place where the immovable property is situated. To do so, he must call on a conciliator of justice (free of charge) or mediator (paid approach) or to a participatory procedure (paid approach with recourse to a lawyer).

In the event of failure, the trustee will be able to appeal to the court.

Please note

The appeal to the court of justice can be exercised for 10 years. After this period, it is no longer possible to contest the illegal works.

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