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A floor plan is the horizontal sectional representation of a building. It shows room layouts, walls, openings, stairs and dimensions with real measurements, providing a reliable basis for planning, tendering, billing and approvals.
Why is a floor plan important?
- Binding basis: Current dimensions and structures reduce planning errors, change orders and duplicate site visits.
- Efficient processes: Sections, elevations, areas and quantities can be derived from a consistent floor plan.
- Interoperability: Clean floor plans can be transferred directly into CAD/BIM, room books and CAFM systems.
- Legal reliability: Traceable dimensions, references to standards and documented tolerances support acceptance, fire safety documentation and energy performance evidence.
How a floor plan is created in practice
- Data capture: Digital building measurement using terrestrial laser scanning (TLS), mobile LiDAR/SLAM or photogrammetry generates point clouds and image data; distance meters are used for detailed measurements during the building survey.
- Quality assurance: Registration, check points, documented tolerances in mm/cm, RMS errors and plausibility checks.
- Derivation/drawing: Define section planes in the point cloud, model walls/openings, structure dimensions/line types/layers, define room boundaries and draw the floor plan.
- Areas and room book: Calculate areas according to the relevant rule set, for example DIN 277; add attributes to rooms such as use, height and zone.
- Handover: Export as DWG/DXF/PDF; for BIM projects, also provide IFC and metadata such as version, units, coordinates and accuracy class.
Types of floor plans
- As-built floor plan: Created from a current survey, not by reusing an old plan.
- Construction/detail floor plan: Detailed components, tolerances and execution details.
- Variant/layout floor plan: Design and occupancy planning, for example workplace layouts or MEP layouts.
- Deformation-accurate floor plan: Representation of real deviations in existing buildings, such as crooked walls or settlement.
Common mistakes/misunderstandings
- Old plan instead of current condition: Historical plans are not proof of current geometry. Always use an up-to-date building survey.
- No standard reference for areas: Without specifying DIN 277 or another rule set, values are difficult to compare.
- Unclear units/coordinates: Confusing metres and millimetres or omitting the origin can lead to follow-on errors.
- Media discontinuities: Manual copying increases the error rate. Direct derivation from the point cloud/model is better.
- Over- or under-detailing: Too much detail inflates files, while too little prevents execution. Align LOD/LOI with the intended purpose.
Floor plan vs. section/elevation
- Floor plan: Horizontal section showing room layouts and dimensions.
- Section/elevation: Vertical representation for heights, build-ups and facade structure.
Best practice: Derive all three and keep them consistent.
FAQ
How is a reliable as-built floor plan created?
Through digital building measurement using TLS/SLAM/photogrammetry, documented tolerances, check points and direct derivation from the point cloud, not by adopting old plans.
Which area rules apply in a floor plan?
For buildings in Germany, DIN 277 is widely used. Depending on the purpose, WoFlV for residential floor area or GEFMA/GIF rules may also be relevant. The applicable rule set should always be stated.
In which formats should I receive floor plans?
DWG/DXF/PDF for 2D, optionally IFC for BIM projects. Metadata on version, units, coordinates and accuracy should be included.