Possible building zones
One of the key criteria is the building zone where the land is located. Multi-family houses can only be built in residential (W), mixed residential/commercial (WG), core (K) or village (D) zones. Multi-family houses are possible in the following zones:
- W2 / W3: Residential zone with 2 or 3 full storeys
- WG 2 / WG 3: Mixed residential/commercial zone with 2 or 3 full storeys
- K 2 / K 3: Core zone with 2 or 3 full storeys, usually with appearance conditions attached
- D 2 / D 3: Village zone with 2 or 3 full storeys, usually with appearance conditions attached
The maximum number of possible full storeys is generally stipulated in building law. Added to this are an attic or loft and a basement.
Further legal criteria and requirements specific to multi-family houses presuppose a plot that is large enough to plan and erect a multi-family house. These include:
- Utilisation ratio: After the building zone, this is the most important factor in deciding whether a multi-family house is possible on a given plot. The utilisation ratio determines how large a building may be in relation to the plot size. The most common ratios are the floor area ratio, area/volume ratio, storey ratio and building coverage ratio.
- Minimum distances: Multi-family houses generally have to allow for larger minimum distances than single-family houses. Distances from street, woods and watercourses also limit the space in the plot available for building.
- Infrastructure: Space for (visitor) parking, a playground and so on must be included when planning a multi-family house.