Many of these terms are, of course, primarily important for architects who initiate a planning application. But the following changes may also be of interest to you as a property owner. It is also important to mention that some of the municipalities have already included these terms in a revision of the building regulations, while others have not yet done so. So at the moment you have to check exactly what the current situation is in each municipality.

And now, the most important thing in a nutshell:

• The decisive terrain used to be determined by the existing course of the ground. Thus, when building a property twenty or thirty years ago, the ground could be changed and this changed fact was valid. Now it is the case that the naturally grown course of the terrain is valid. That is, the way the ground used to be before it was ever changed. If the old condition can no longer be ascertained, the course of the terrain of the surroundings is taken as a basis. Now, however, there are rumours in certain municipalities that new court decisions are already calling this «new practice» into question. It therefore remains exciting how the evolved terrain will be interpreted in the future. At the same time, this uncertainty is not ideal for planning security.
• Buildings that are no higher than 1.50 metres and have a usable area of no more than two square metres are no longer considered buildings and can be constructed anywhere, even directly on a border. They do not require a building permit.
• In contrast, there are small buildings that do not require a permit, which may be a maximum of two and a half metres high and have a maximum floor area of six square metres. They are subject to a reduced boundary and building clearance and no building permit is required for them either.
• Protruding building parts may protrude a maximum of two metres into the boundary distance and no longer one and a half metres, as was previously the case, for half and not one third of the façade length. In addition, the projections may extend to the ground floor.
• The knee-storey height was increased from 0.9 metres to 1.5 metres. However, it is measured on the outside of the roof and no longer on the inside.
• The minimum clear height is measured between the upper edge of the finished floor and the lower edge of the finished ceiling or joist layer. It is still 2.4 metres and in core zones 2.3 metres.
• In attics, the height must be at least over half of the floor area.

• Full storeys are storeys other than the basement, roof and attic storeys. The roof, attic and basement storeys may also replace a full storey, but when added together they may never exceed the number of a full storey.

• The chargeable plot area in the case of a forest distance now corresponds to the entire area that lies within the building zone. Previously, it was only the first 15 metres calculated back from the forest distance line. The area of house access roads is counted for the utilisation/building mass calculation. The areas of the basic, coarse and fine development are not counted. According to experts, there is a certain uncertainty as to how the terms are to be interpreted.

• In the case of the building mass figure, the «above-ground enclosed space» is replaced by the building volume above the relevant terrain to the chargeable plot area. An additional building mass figure for volumes that serve to save energy can be used, namely up to twenty percent of the zonal basic figure.

• The green area figure is replaced by the open space figure. It is the ratio of the chargeable green area to the chargeable plot area. It is essential that the chargeable green area only includes parts of the plot that are not sealed and do not serve as storage areas, i.e. pure garden areas. This is likely to have a significant influence and decisively reduce the permitted building area.

The building and zoning ordinances of the municipalities in the canton of Zurich can be accessed online via the municipal websites. There you can see the current status. If you would like to delve deeper into the subject, we recommend the comprehensive workbook «Harmonisierung der Baubegriffe und Messweisen nach IVHB im Kanton Zürich» by Suter von Känel Wild, which we used as a source for this article with their permission. We would like to take this opportunity to thank them.