Property types
Creating a floor plan for an apartment building
With a multi-unit building the purpose of the plan changes: it stops being a sales image and becomes a management document. Selling a block means selling lettable areas, and those have to be evidenced per unit — as a number that reconciles with the rent roll, not just as a nice drawing.
At the same time the classic need remains: letting a single flat in the building requires a plan of that one unit. Producing both from the same project avoids the duplicate maintenance that almost always ends in contradictory figures.
One project, several units per storey
Create one plan per storey and separate the units unambiguously — either by prefixing room labels with the unit number or by keeping a plan per unit. What matters is that every square metre belongs to exactly one unit.
Stairwells, lifts, corridors, laundry and drying rooms and cellar passages are common areas. They belong on the plan but not in any flat. If they are not kept separate you end up with unit areas that sum to more than the building.
- Name every unit clearly, for example Unit 3, first floor
- Mark common areas as common
- Assign cellar lockers to units without counting them as living area
- Keep a per-storey total and reconcile it with the rent roll
The figures a property manager needs
Three numbers matter for management: living area per unit, the sum of living areas as the basis for apportioning costs, and the usable area of ancillary rooms. Keep them apart in the plan so service charges do not rest on estimated shares.
The editor derives each room's area from the geometry and can apply the German living-area factors on request: normally a quarter for balconies, a half for unheated conservatories, zero for cellars and laundry rooms.
Output for sale and for the asset file
To sell the whole building, produce a PDF with one page per storey plus a schedule of units. To let a single flat, export just that unit as its own PDF or image.
If the data has to move into an agency system, the OpenImmo XML export carries living area, usable area and room count in structured form — considerably more reliable than retyping figures out of a PDF.
Frequently asked questions
How do I allocate common areas?
You do not allocate them to a flat. Stairwells, corridors, laundry and drying rooms are common areas and sit outside every unit's living area. Show them on the plan and track them separately in management.
Do I need a separate plan per flat?
For letting, yes — viewers only want to see their own unit. For the building file, a storey plan with clear unit markings is enough. Both outputs come from the same project.
How do I avoid contradictory area figures?
By having one source. As soon as areas are maintained separately in the listing, the tenancy agreement and the service-charge statement, they drift apart. One plan per storey with computed room areas is the more defensible basis.