Floor area

In the construction industry, the floor area refers to the total built-up area of a building, measured along the outer edges of the exterior walls on the ground floor. It is a key term in real estate appraisal, planning law, and building permits, and serves as the basis for calculating the floor area ratio (FAR). The floor area should not be confused with the living area (according to the Living Area Ordinance) or the usable area-it includes all parts of the building, including exterior walls, staircases, and non-habitable rooms.

Floor Area vs. Living Area vs. Usable Area

The living area (according to the Living Area Ordinance) covers only the eligible area within the dwelling-exterior walls, staircases, basements, and roof areas under 1 m in height are not fully accounted for. The usable area (DIN 277) encompasses all areas within the building according to usage categories. The floor area, on the other hand, is the built-up land area and thus the planning-law-relevant figure for calculating the floor area ratio (FAR).

Calculation of the Floor Area Ratio (FAR)

The floor area ratio is calculated by dividing the building’s floor area by the land area: FAR = Building Floor Area / Land Area. A floor area ratio (FAR) of 0.4 specified in the zoning plan allows for a maximum floor area of 200 m² on a 500 m² lot. Garages, parking spaces, terraces, and other ancillary facilities are considered separately in the FAR calculation pursuant to § 19 of the Federal Building Code (BauNVO) and may be added up to an excess of 50% of the specified FAR.

Significance for Valuation and Purchase

In real estate valuation-particularly in the asset value method-the floor area is a key input value for calculating the building’s asset value. Together with the ceiling height, this yields the gross floor area (GFA), which serves as the basis for cost estimates according to DIN 276 and for insurance value calculations. When purchasing a plot of land, the potential floor area of the planned building should be calculated based on the GRZ specified in the zoning plan to assess the actual development potential.

Practical Tip for Property Owners in Nuremberg and Franconia

In the Nuremberg metropolitan region, there are significant differences in floor area ratio (FAR) regulations: Locations near the city center often allow higher FAR values (0.6-0.8), while single-family home areas on the outskirts are typically limited to 0.3-0.4. Anyone purchasing a property who wishes to build or expand on it should first check how much of the lot is already built upon and how much reserve area remains. We are happy to help you realistically assess a property’s development potential.

Frequently Asked Questions

Do terraces and carports count toward the lot area?

Yes, with restrictions. Terraces, carports, driveways, and similar ancillary structures are included in the floor area ratio (FAR) under Section 19(4) of the Federal Building Code (BauNVO), but may result in the specified FAR being exceeded by 50% (the so-called permissible FAR 2). The zoning plan may provide for exceptions to this rule.

How is the floor area of an L-shaped building calculated?

The floor area is calculated as the sum of the individual rectangles that make up the building, minus the open spaces created by the L-shape. The outer dimensions of the exterior walls are decisive.

Is the floor area specified in the declaration of division for a condominium?

Generally not. The declaration of division contains information on the living area and the co-ownership shares. The floor area of the entire building is derived from the official site plan and the construction documents.

Floor Area and Construction Cost Planning

Along with the floor area, the floor area is a key input value for cost estimation according to DIN 276. For early-stage project cost planning, cost indicators per square meter of gross floor area (GFA) are frequently used. The gross floor area encompasses all floors, including the basement and attic, and is therefore larger than the simple floor area of the ground floor. Confusing these terms can lead to significant miscalculations.

For insurance purposes-such as residential building insurance-great importance is often attached to the living area or the gross floor area (GFA). Here, too, a careful distinction is important: A floor area that is stated too low can lead to underinsurance in the event of a claim, in which case the insurance company will only pay a proportionate amount.

Anyone purchasing a property in Nuremberg who wishes to check its buildability should first review the zoning plan, note the floor area ratio (FAR), and then calculate the maximum possible floor area. We are happy to assist with this assessment as part of our consulting services.

Floor Area in the Declaration of Division and in Condominium Ownership

In condominium law (WEG), the floor area of the entire building plays an important role in calculating co-ownership shares. These are specified in the declaration of division and are often based on the ratio of the individual units of exclusive ownership to the total living space or usable area of the building. Although the floor area itself is generally not explicitly stated in the declaration of division, it forms the planning law basis for all further area calculations. In the case of additions or extensions to a residential building that is divided into condominiums, an increase in the floor area requires the consent of all condominium owners, as it affects the common property.

Floor Area and Zoning Plans: Specifications in Detail

In addition to the floor area ratio, zoning plans often specify other dimensions that directly or indirectly limit the floor area: building boundaries and building lines define the area within which construction is permitted on the property-regardless of the floor area theoretically possible based on the floor area ratio. Buildable land areas may be smaller than the FAR value suggests if setback distances under the Bavarian Building Code (BayBO), building boundaries, or water body setback rules further restrict the buildable area. Anyone wishing to determine the potential floor area of their property must therefore consider not only the FAR but also the graphic specifications of the zoning plan and the setback distance rules of the Bavarian Building Code.

Floor Area and Sustainability Aspects

A conscious consideration of floor area also has ecological relevance: the larger the sealed floor area, the less soil is available for infiltration, greening, and climate regulation. Many new zoning plans in Nuremberg and the metropolitan region therefore stipulate greening requirements for undeveloped land or green roof mandates to mitigate the negative consequences of high soil sealing. For developers, this means: The floor area ratio (FAR) should not necessarily be maximized to the legally permitted limit-deliberately staying below the FAR can enhance living comfort through more green space and positively impact property value in the long term.

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