When it comes to real estate, there are notions that are not always easy to grasp. When selling or renting a property, you will be asked to provide information on the size of the property. Surface law Boutin or surface law Carrez, exceptions and obligations… There are nuances in the calculations to be established according to the housing situation.
The living area, known as the “Boutin law surface”, corresponds to the surface area of the living spaces of the dwelling. Ittakes into account rooms with a ceiling height greater than or equal to 1.80 m excluding the area of walls, partitions, doorways and windows, stairwells and steps, as well as cellars, garages, attics and verandas. The Boutin law surface must always be mentioned in the advertisements of empty dwellings for rent, as well as during the sale of dwellings for residential use, in condominium or not.
What is not taken into account in the living space?
The calculation of the living area does not take into account certain parts or parts of a property:
– the undeveloped attic;
– cellars;
– basements;
– discounts;
– garages;
– terraces, balconies or loggias;
– verandas;
– dryers outside the dwelling;
– the common areas;
– dependencies.
All other spaces must be taken into account in the calculation, provided that a ceiling height greater than or equal to 1.80 m is justified.
How to calculate living space
In order to measure the living area of a property, it is necessary to add up all the areas taken into account in the calculation. As a reminder, the area corresponds to the length of a space multiplied by its width. Each room with a ceiling height greater than or equal to 1.80 m must be included in the calculation: living room, kitchen, dining room, bathroom, toilet, bedrooms, corridors, cupboards, attic space,etc.
To obtain an accurate result, and thus avoid a mistake that could be expensive, it is strongly recommended to call a professional. You can find a list of approved diagnosticians on the website of the Ministry of Ecological Transition. The calculation of the living area has no validity period. If no extension is carried out in the lodge, it is therefore not necessary to repeat the surface diagnosis.
The surface Carrez law
The Law No. 96-1107 of 18 December 1996, known as the Carrez law, concerns real estate in co-ownership, i.e. structures divided into several separate dwellings, surrounded by common areas. They can be vertical (apartment in a building) or horizontal (individual house in a subdivision). The Carrez law surface is calculated according to the following principles:
– All living areas with a ceiling height of at least 1.80 m are taken into account.
– Attics, storerooms, sheds, verandas and basements are also taken into account. However, there is an exception for cellars, garages and parking lots which are excluded from the calculation.
– The floor area of walls, partitions, ducts, stairwells, steps, doorways and windows, balconies and terraces is not taken into account.
The mention of the Carrez law surface is mandatory in the compromises and promises of sale of co-ownership lots, as well as in the deed of sale. Indeed, the lease contracting the rental of a property, empty or furnished, as a principal residence, must contain the exact surface area of the property. This information is used to verify the decency of the rental, i.e. that the surface area is greater than 9 m2. In case of error, the tenant can ask the owner to reduce the rent. This calculation also allows the tax authorities to evaluate the cadastral rental value, and therefore the amount of the housing and property taxes.
Even if nothing obliges the owners to call upon a professional, it is recommended to entrust the measurement to an approved diagnostician, in order to obtain a right and incontestable calculation.
Habitable surface, useful surface and floor area, what are the differences ?
When selling or renting a property, you will always be asked to specify the surface area of your home. However, there are a number of measurements among which it is sometimes difficult to find your way.
The floor area is an essential measurement for construction work, particularly when it comes to issuing a building permit or planning permission. It has been used recently and replaces the notions of gross floor area (SHOB) and net floor area (SHON). This measure is obtained by adding the floor areas of all levels closed and covered from the bare interior of the facades, ie from the wall as seen from inside the building, without taking into account the thickness of exterior walls and insulating materials. Excluded from the measurement are areas with a ceiling height of less than 1.80 m.
The living area, also called “surface Boutin law” corresponds to the floor area from which we deduct the surface of walls and partitions, stairwells and steps, doorways and windows. It is therefore the surface area in which it is possible to live or that it is possible to develop. It includes all the spaces whose ceiling height is greater than or equal to 1.80 m with the exception of terraces, balconies, loggias, verandas, garages and undeveloped attics. The mention of the living area is mandatory for the rental of a property. It also allows to inform potential buyers when selling your property, but also to calculate the property tax and the housing tax.
The useful surface, defined by Article D356-16 of the Construction and Housing Code, corresponds to the living area to which is added half of the surface of the annexes reserved for the use of the resident. The common portions are therefore excluded from the calculation. Again, only spaces over 1.80 m high ceilings are taken into account. It can be balconies, loggias, verandas, cellars, basements, attics, converted attics, sheds, workshops, cellars, etc. Gardens, garages and court yards are not included in the calculation.
Obtain proof of living space
The measurement of the living area of a dwelling is mandatory before it is rented. Indeed, the exact area must appear on real estate ads, regardless of their format (digital or paper), but also with the lease at the time of its signature.
When you call on a real estate diagnostician to carry out a diagnosis surface Boutin law, he gives you a certificate of living space to append to the lease. This document and the skills of the professional guarantee you an accurate and indisputable measurement. The latter engages its responsibility in case of error that could lead to a dispute.
Improper calculations of living space: the consequences
In the event of a calculation error in the context of a real estate transaction, the buyer may request the cancellation of the sale within one month. If the new calculation of the areareveals that the area indicated in the deed of sale is 5 % higher than the actual area, the buyer may demand a reduction in the selling price.
The same applies to rentals. Thus, a tenant can claim the reduction of his rent if the measurement of the living area of his dwelling provided with his lease is erroneous.