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Structural Data: Definitions

The building age is defined as the year in which a building was constructed. In data on the construction sector provided by Germany’s Federal Statistical Office, domestic buildings are classified by building age. The age classes applied here are practically the same as those established by the Statistical Office to analyse the stock of domestic buildings

The gross floor area GFA is the total area of all floors, vertical surfaces and ceilings of a building over all storeys. The gross floor area is made up of the net floor area and the construction area (DIN 277-1 2005).

The gross building volume is the total volume of all interior spaces in a building over the gross floor area. This total volume is enclosed by the outer boundary surfaces of the foundation, the exterior walls and the roof (including the dormers and skylights) (DIN 277-1 2005).

The different floor areas and volumes used here are based on definitions specified in DIN 277 (2005 version). This regulates the “floor areas and interior volumes of buildings” and is subdivided into three parts:

1.    DIN 277-1: Terminology, basis of calculation.

2.    DIN 277-2: Classification of net floor area into usable area, service area and circulation area.

3.    DIN 277-3: Quantities and reference units.

The definitions of the individual floor areas and volumes (usable area, service area, circulation area, net floor area, construction area, gross floor area, gross volume) are given separately.

A revised DIN 277-1 “Floor areas and volumes of buildings – Part 1: Building construction” has been in force since January 2016. The older version DIN 277-1 (2005) as well as DIN 277-2 (2005) were shortened and compiled to created DIN 277-1 (2016). Furthermore, some terms were revised: Technische Funktionsfläche became Technikfläche (service area), Netto-Grundfläche became Netto-Raumfläche (net floor area), and Nutzfläche became Nutzungsfläche (usable area).

These changes are not relevant to the databank as the presented data on buildings and infrastructure are based on calculations undertaken before 2016.

These are floor areas according to DIN 277 (usable area, service area, circulation area, net floor area, construction area, gross floor area) as well as areas of building components (foundation, exterior walls, interior walls, ceilings, roof, other).

The building floor area is the area over which the building is in contact with the soil. It corresponds to the gross area of the ground floor or the so-called building “footprint”, and is frequently termed the “built-up area”.

The construction area is the sum of all areas of vertical building components over all building storeys (DIN 277-1 2005).

Materials are determined individually and specified in aggregate form for building components and material groups as well as total masses. The table on building materials classifies the individual materials to material groups.

The net floor area is the sum of all areas on all storeys of a building minus the construction area. The net floor area can be subdivided into usable area UA, service area SA and circulation area CA (DIN 277-1 2005).

The usable area is classified into various classes of actual use. According to DIN 277-2: 2005-02, Table 1, Nos. 1 to 7, these are: living space; office space, space for manufacturing, manual and machine production; space for experiments; space for storage, distribution and sales; space for training, education and culture; space for healthcare and treatment; other forms of usable space.

In the previous version of DIN 277 from 1987, the usable area was subdivided into main usable area and residual usable area (Haupt- und Nebennutzfläche). This classification was adopted in the case of domestic buildings as this allows a clear distinction between the main use “living” and required secondary uses of floor space such as, for example as box rooms, cellars, attics, drying rooms and/or laundry rooms.

A representative building (whether a real or invented building) is a typical example of a building group (here age classes). It presents all characteristic features of these groups.

These are derived from diverse numbers of real domestic buildings – so-called representative buildings – and reflect the average building and dwelling sizes, the structural designs as well as the employed materials in each respective building period.

Service areas are those areas where a building’s technical equipment is housed. According to DIN 277-2: 2005-02, Table 1, No. 8, these are areas dedicated to heating and hot water production, the supply of electricity or telecommunications.  

Circulation areas are those spaces enabling the movement of occupants. According to DIN 277-2: 2005-02, Table 1, No. 9, these include stairways, lift shafts, corridors or hallways. 

This is the gross interior volume of a building according to DIN 277.

In der DIN 277-1:2016-01 zu Grundflächen und Rauminhalten im Bauwesen (Hochbau) wird nur die Nutzungsfläche thematisiert. Eine Unterschiedung dieser in Haupt- und Nebennutzfläche wird - wie in den Vorgängerversionen üblich - nicht mehr vorgenommen. Dennoch wurde diese Unterteilung hier bei den Wohngebäuden aufgegriffen. Grund dafür war die Möglichkeit der konsequenten Trennung der Hauptnutzung „Wohnen“ von den darüber hinaus erforderlichen Nebennutzungen, wie z. B. Abstell-, Keller-, Boden-, Trockenräume und/oder Waschküchen.

Die Hauptnutzfläche setzt sich aus der Summe der Grundflächen der folgenden Nutzungsarten zusammen: (1) Wohnen und Aufenthalt, (2) Büroarbeit, (3) Produktion, Hand- und Maschinenarbeit, Experimente, (4) Lagern, Verteilen, Verkaufen, (5) Bildung, Unterricht und Kultur, (6) Heilen und Pflegen (Weiß 1995). Bei den Wohngebäuden ergibt sich die Hauptnutzfläche dementsprechend aus der Summe der Grundflächen aller Wohnräume.

In der DIN 277-1:2016-01 zu Grundflächen und Rauminhalten im Bauwesen (Hochbau) wird nur die Nutzungsfläche thematisiert. Eine Unterschiedung dieser in Haupt- und Nebennutzfläche wird - wie in den Vorgängerversionen üblich - nicht mehr vorgenommen. Dennoch wurde diese Unterteilung hier bei den Wohngebäuden aufgegriffen. Grund dafür war die Möglichkeit der konsequenten Trennung der Hauptnutzung „Wohnen“ von den gleichfalls erforderlichen Nebennutzungen, wie z. B. Abstell-, Keller-, Boden-, Trockenräume und/oder Waschküchen.

Die Nebennutzfläche setzt sich aus der Summe der Grundflächen für sonstige Nutzungen - Sanitärräume, Garderoben, Abstellräume, Fahrzeugabstellflächen, Fahrgastflächen, Räume für zentrale Technik, Schutzräume - zusammen (Weiß 1995). Bei den Wohngebäuden ergibt sich die Nebennutzfläche dementsprechend aus der Summe der Grundflächen aller Abstell-, Keller-, Boden-, Trockenräume etc.