Vertikal förtätning : En del av ett hållbart stadsbyggande?

Sammanfattning: This is an essay concerning the density of the city. An increasing amount of today’s cities have a shortage of space available for the erection of new buildings and settlements, especially in areas close to the city-centre. New buildings and settlements are therefore often found in the outskirts of the city, resulting in long distances between work and living for many people. These long distances are a waste of limited resources and are inconsistent with the vision of the sustainable city. The challenge for the future is to insert new buildings and settlements in the existing city-structure and in this way reduce the distances between different city-functions. The density of the city can be increased in two different ways; by inserting new buildings between existing ones or by extension existing buildings, for example by an additional floor. The subject of this essay is to examine the latter way of increasing the city’s density, that is through extensions of existing buildings by building on rooftops, so called “vertical concentration”. Vertical concentration lacks tradition in Sweden, but is quite common on the European continent, especially in the Netherlands. This essay therefore aims to examine the conditions for vertical concentration to be applied in the city-planning of Sweden, with the city of Norrköping as a case-study. A circumstance which has greatly simplified the implementation of vertical concentration in Sweden came with the introduction of a new regulation concerning “three-dimensional property formation” in 2004. For example, this regulation enables a floor in a building to become a property of its own, separated from the rest of the building. Vertical concentration gives new opportunities to obtain a mix between spaces for living and working in the same building. For instance it enables a floor of apartments to be put on top of a building consisting of offices. An important aspect to keep in mind when applying vertical concentration is to avoid an impoverishment of city-functions, for example by adding a floor of apartments on top of a dwelling complex. An analysis was carried out of Norrköping and its buildings in order to investigate the town’s suitability for vertical concentration. For a building to be used for vertical concentration it had to pass a number of restrictions formulated in different rules and regulations concerning city-planning. The analysis gave the answer that 137 hectare (approximately 191 football-fields) of rooftops in Norrköping could be used for vertical concentration, a result that exceeded the municipality’s expectations.