In which case should an architect be called upon?
Verified 07 September 2026 - Entreprendre Service Public / (Prime Minister)
As a rule, recourse to the architect is mandatory to develop the plans for the building permit, in particular for legal persons. In some cases, this remedy is not not required for individuals and farmers who build or modify their buildings for their own use. We present the regulations to you.
Warning
The use of an architect is never mandatory for projects subject to prior declaration of works.
The use of the architect concerns building permit files in the following situations:
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Application for a building permit by an individual
The requirement to hire an architect depends on the type of works. The change of destination of a premises or a building may also require the use of an architect.
New construction
The obligation to call on an architect depends on the floor area of construction.
Floor area of more than 150 m²
The use of an architect mandatory.
Warning
Where there are several buildings of the same use (e.g. dwelling) on the same land, only the floor area of the building for which planning permission is requested shall be taken into account.
Floor area of less than 150 m²
The use of an architect is not required.
Warning
Where there are several buildings of the same use (e.g. dwelling) on the same land, only the floor area of the building for which planning permission is requested shall be taken into account.
Expansion of an existing building
The obligation to call on an architect depends on the floor area building before and after works.
Floor area of more than 150 m² before works
If the project is subject to a building permit, the use of an architect is mandatory.
Example :
The use of an architect is mandatory for an extension of more than 40 m² subject to building permit in an urban area of one MORE: titleContent (more than 20 m² outside) on a detached house of more than 150 m² before works.
Floor area of more than 150 m² after works
The use of an architect mandatory.
Building floor area of less than 150 m² after works
The use of an architect is not required.
Greenhouse
You must hire an architect to build or expand an existing greenhouse if its dimensions after works exceed one of the following:
- 4 m height of the right foot (vertical upright)
- 2,000 m² of floor area
- 2,000 m² of right of way on the ground.
Change of destination
The building permit is mandatory for the change of destination of a building or premises when it is accompanied by the modification of the supporting structures or the facade of the building.
The requirement to hire an architect depends on the surface of the building or premises.
Floor area of the building or premises of more than 150 m²
The use of an architect mandatory .
Floor area of the building or premises less than or equal to 150 m²
The use of an architect is not required.
Application for a building permit by a farmer or a farm equipment co-operative
The requirement to hire an architect depends on the type of works (building or expanding an agricultural building or greenhouse). The change of destination of a premises or a building may also require the use of an architect.
New construction of a farm building
The obligation to use an architect to build an agricultural building (e.g. shed) depends on the floor area of construction.
Floor area of more than 800 m²
The use of an architect mandatory.
Warning
Where there are several agricultural buildings of the same use on the same land, only the floor area of the building for which planning permission is requested shall be taken into account.
Floor area of less than 800 m²
The use of an architect is not required.
Warning
Where there are several agricultural buildings of the same use on the same land, only the floor area of the building for which planning permission is requested shall be taken into account.
Expansion of an existing farm building
The obligation to call on an architect depends on the floor area the farm building before and after the works.
Floor area of more than 800 m² before works
If the project is subject to a building permit, the use of an architect is mandatory.
Floor area of more than 800 m² after works
The use of an architect mandatory.
Building floor area of less than 800 m² after works
The use of an architect is not required.
Greenhouse
You must hire an architect to build or expand a greenhouse if its dimensions after works exceed one of the following:
- 4 m height of the right foot (vertical upright)
- 2,000 m² of floor area
- 2,000 m² of right of way on the ground.
Change of destination
The building permit is mandatory for the change of destination of a building or premises when it is accompanied by the modification of the supporting structures or the facade of the building.
The requirement to hire an architect depends on the surface of the building or premises.
Floor area of the building or premises of more than 150 m²
The use of an architect mandatory .
Floor area of the building or premises less than or equal to 150 m²
The use of an architect is not required.
Application for a building permit by a legal person
One legal person must use the services of an architect regardless of the building project or works subject to building permits.
Who can help me?
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For information on urban planning regulation and administrative procedures
For more information on this subject, you can contact Allô Service Public.
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