Gross floor area (GFA): definition, calculation and implications for your real estate projects
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In Switzerland, the gross floor area (GFA) constitutes a key indicator in the planning, evaluation and authorisation of real estate projects. For developers, investors or architects, understanding what this concept covers is essential in order to control the building potential of a plot and comply with local regulations.
What is gross floor area (GFA)?
The gross floor area (GFA) designates the sum of the surfaces of all the levels of a building, measured from the outer face of the walls. It therefore includes:
- Habitable spaces (housing, offices, etc.)
- Corridors, halls, technical rooms
- Load-bearing walls and interior partitions
- Ancillary areas integrated into the constructed volume (such as certain balconies, loggias or common areas depending on the canton)
The GFA must not be confused with the gross usable floor area (GUFA), which excludes non-usable elements such as walls or technical shafts. The GFA is therefore a more global indicator, often used in density calculations or in building permit procedures.
How is GFA calculated?
The calculation method may vary slightly from one canton to another, but in general these main principles are followed:
- All constructed surfaces per floor are added up, including basements and convertible attics.
- Measurement is taken from the outside of the walls (façades).
- Certain elements are excluded according to local regulations: open balconies, uncovered terraces, etc.
Practical example:
A 3-storey building comprising 200 m² per floor and 50 m² of technical areas will have a total GFA of 600 m² (3 x 200), to which ancillary areas may or may not be added depending on the canton’s criteria.
Why is GFA important in real estate?
- Determine the building potential
The GFA is a central tool to assess whether a project complies with the density indices authorised by the municipality or canton. Depending on the plot and the land use plan, a plot may have a land use coefficient (CUS) or land use index (IUS) that limits the maximum authorised GFA. - Manage projects in full compliance
Building permits include strict requirements regarding GFA. A poor estimate can lead to refusals, delays or costly modifications. Calling on experts such as FGP Swiss & Alps makes it possible to anticipate these constraints and secure each stage of development. - Increase the value of the property
A well-managed, well-used and optimised GFA can improve the land value of a property. It also influences the financial ratios used in asset valuations, project structuring or investor calls.
FGP Swiss & Alps supports you
With recognised expertise in luxury real estate, FGP Swiss & Alps helps you to:
- Estimate the actual and regulatory GFA of a project
- Optimise the architectural design according to local rules
- Prepare files compliant with municipal and cantonal requirements
- Enhance land assets in a sustainable and profitable way
Our teams work hand in hand with urban planners, notaries, architects and local authorities to provide a tailor-made approach to each operation.
FAQ on Gross Floor Area (GFA) in Switzerland
What is the difference between GFA, usable GFA and usable floor area?
GFA (Gross Floor Area) includes all built areas, including walls and partitions.
Usable GFA excludes non-usable elements such as load-bearing walls.
Usable floor area corresponds to the spaces that are actually usable (housing, offices, premises).
Which elements are included in GFA?
The GFA takes into account:
Habitable rooms,
Circulations (corridors, halls),
Technical rooms,
Load-bearing walls and interior partitions,
Certain balconies and loggias, depending on the canton.
Why is GFA important for a real estate project?
The GFA determines the building potential of a plot, the project’s compliance with the land use plan, and influences the land value of the property. It is also essential for obtaining a building permit.
How to calculate the GFA of a building?
One adds up all the built areas per floor, measured from the outer face of the walls. Depending on cantonal regulations, some spaces such as open balconies or uncovered terraces may be excluded.
Does GFA impact the price of a property?
Yes. A well-optimised GFA increases the patrimonial value and the profitability of a project. It is notably used in land valuations, density calculations and financial structuring.
