Knowledge
DIN 277 — Floor Areas and Volumes in Building Construction
Gross floor area, net room area, usable area and gross volume explained: which figures the standard defines, how they relate and what they are used for.
DIN 277 is titled "Floor areas and volumes in building construction" and lays down how the areas and volumes of a building are determined and named consistently. It is thus the technical counterpart to the Living Space Ordinance — and produces different figures for the same building.
What the standard is for
Unlike the Living Space Ordinance, DIN 277 does not assess residential quality but describes the structure neutrally. It creates a common language for what has been measured and makes buildings comparable with one another. Typical applications:
- Determining construction costs, in particular in conjunction with DIN 276
- Cost estimates and cost-efficiency comparisons during planning
- Depreciated replacement cost valuation in market value reports
- Setting building insurance sums via the gross volume
- Area figures for commercial property, to which the WoFlV does not apply
The area metrics and how they relate
The standard builds its metrics on one another. Once the system is understood, any figure in an expert report can be placed:
| Abbreviation | Term | What it means |
|---|---|---|
| BGF | Gross floor area | The total floor area of all storeys, measured to the outer boundaries — including the areas occupied by the structure. |
| KGF | Construction floor area | The share taken up by structural elements: walls, columns, shafts. |
| NRF | Net room area | The gross floor area less the construction floor area — that is, the area inside the rooms. |
| NUF | Usable area | The part of the net room area that serves the actual purpose of the building. |
| TF | Services area | Areas for technical installations supplying and servicing the building, such as heating and ventilation plant rooms. |
| VF | Circulation area | Areas for access: corridors, stairwells, entrances. |
Two relationships are worth remembering: the gross floor area is made up of the net room area and the construction floor area. And the net room area divides into usable area, services area and circulation area.
The volumes
| Abbreviation | Term | What it means |
|---|---|---|
| BRI | Gross volume | The total volume of the structure, bounded by its outer enclosing surfaces. |
| NRI | Net volume | The volume of the rooms belonging to the net room area. |
| KRI | Construction volume | The difference between gross and net volume, that is, the volume of the building elements. |
How a gross volume is determined and documented in practice is shown on our service page BRI calculation to DIN 277.
Standard case and special case: R and S
Not every part of a building is enclosed to the same degree. The current edition of the standard therefore distinguishes the standard case (R) — interior spaces enclosed on all sides — from the special case (S), which includes loggias, balconies and roof terraces. Earlier editions worked with the letters a, b and c instead.
This distinction is why an area under DIN 277 cannot simply be compared with a living space figure: outdoor areas are reported separately, but not reduced to a quarter or a half as they are under the WoFlV.
Editions of the standard
DIN 277 dates back to 1934 and has been revised several times. Significant editions are 1987, 2005 — when it was split into DIN 277-1 and DIN 277-2 — 2016, and the edition governing today, DIN 277:2021-08. Because terms and definitions have shifted between editions, every calculation should state which edition it follows.
Relationship to the Living Space Ordinance
The two sets of rules stand alongside one another and are not mutually exclusive. The Living Space Ordinance applies to publicly subsidised housing and is generally used in the residential sector beyond that; it describes the lettable and saleable area. DIN 277, by contrast, describes the structure and its results deviate considerably — as a rule upwards.
Which calculation is required when, and why the figures diverge, is explained on the page WoFlV or DIN 277.
Frequently asked questions
What is the difference between gross floor area and net room area?
The gross floor area covers the entire storey including the areas occupied by walls, columns and shafts. Deduct this construction floor area and the net room area remains — that is, the area actually available inside the rooms.
Is the usable area the same as the living space?
No. The usable area under DIN 277 is the part of the net room area that serves the actual purpose of the building; circulation and services areas are not included. The living space under the WoFlV follows a different system and, for example, counts low parts of rooms and balconies only in part.
What is the gross volume used for?
The gross volume describes the enclosed volume of a building in cubic metres. It is used above all for cost estimates, depreciated replacement cost valuations and setting building insurance sums.
What do the designations R and S mean?
The current edition of the standard distinguishes areas by how far they are enclosed: R denotes the standard case of interior spaces enclosed on all sides, S denotes special cases such as loggias, balconies or roof terraces. Earlier editions used the letters a, b and c for this.
Which edition of DIN 277 currently applies?
The governing edition is DIN 277:2021-08. The standard dates back to 1934; significant earlier editions are from 1987, 2005 (split into DIN 277-1 and DIN 277-2) and 2016. Which edition applies in an individual case may follow from the contract or the brief.
More knowledge pages
These pages are no substitute for legal advice or an assessment of your individual case. For a robust calculation, confirmed by a certified surveyor where required, see our living space calculation or get in touch with us.