How many flats fit on a plot

For every zone the spatial plan sets the land use and the type of buildings allowed in it, including the number of flats and storeys. In a zone meant for family houses a building with several flats is as a rule not possible, however large the plot.

Under the Building Act, a building with three or more flats is a multi unit residential building. Its permit is issued on the main design of all disciplines, not on a concept design as for a house. Where an urban development plan is required but has not been adopted yet, no permit can be issued for a new building.

For building inside a building zone the plan must set the maximum site coverage ratio (kig), the maximum floor area ratio (kis) and the maximum gross floor area. Where needed it also sets the floor area ratio separately for storeys above and below ground.

Kig sets how much of the plot may be under the building, kis how large the gross area of all storeys together may be. That gives the upper limit of floor area, and from it a rough number of flats. Gross area is not sellable area: walls, stairs, the lift and shared spaces come off it.

The plan must set the maximum facade height and the maximum number of storeys above and below ground. On a sloping site it sets two heights, measured from the highest and from the lowest level of the finished ground along the facade.

What counts as which storey is defined precisely. A basement is buried for more than half its volume, a lower ground floor for up to half, and an attic has a knee wall of up to 1.2 m. A set back top floor under a flat roof may take up at most 75 % of the footprint of the enclosed parts of the building and must be set back on the street side. Such differences often decide whether one more floor of flats fits.

The plan sets the minimum number of parking spaces that must be provided on the plot and the minimum share of natural ground. For a building, parking is often what really limits the number of flats: spaces and their access take up part of the plot that can be neither building nor green.

For new buildings with more than two storeys above ground, the Spatial Plans Ordinance requires, when undeveloped areas are planned, a distance from the boundary of at least half the building height and not less than 3 m. The exact distances for your plot are set by the plan.

A residential building with ten or more flats must meet the Technical Regulation on accessibility of buildings for persons with disabilities and reduced mobility. For every ten flats one must be easily adaptable, and the solution is shown already in the main design. Without it no permit is issued.

Such a flat is as a rule on the ground floor, and it must be reachable from the public footpath without obstacles. A level difference of more than 120 cm is overcome with a lift. Of all parking spaces at the building 5 % must be accessible, at least one. When the number of flats is close to ten, this is worth weighing already in the analysis.

We check all of this for your plot and send a written report within 1 to 2 weeks. It contains the plan figures applied to the plot, the largest building volume in a 3D model, the rough number and size of flats and an estimate of the sellable area.

With the report you decide on buying the plot and on the design. If we go on, we develop the flat layouts and the permit design from the same 3D model.