Gröna tak - En del av framtidens städer

Sammanfattning: This thesis is made in order to review green roofs as an alternative roof covering. We have studied the common sources why green roofs are not selected and its advantages and construction. Green Roofs have existed in different shapes since year 900 before Christ, when the gardens were built up with trees, bushes and climbing root in pots. In Scandinavia, many centuries later, roof coverings were made of grass and turf. These green roofs however had one disadvantage: they were very flammable. The green roofs of today were created during the 1960s in Germany where the usual roof cover is sedum. In Metropolises today the natural green areas are replaced with buildings and streets. These hard surfaces absorb sun energy which gives a higher temperature than the countryside. The disadvantage is that the temperature inside the buildings will increase and gives higher energy consumption. Also the storm water affects by the hard surface since it doesn´t absorb the rainwater which leads to flood when the drainage pipes is not dimensioned for such amount of water. If the natural green area is replaced by constructed green areas, like green roofs or facades, the city environment could be improved. It becomes a steady climate, lower energy supply, lower risk for flood at the same time as it affects the human common wealth positively. Today the city of Helsingborg is developing a plan for a radical urban renewal. By digging down a railway south of Knutpunkten parts of the city center can be linked together. H+, as the project is called, includes renewal of a former port area Södra hamnen, as well as the former industrial areas of Söder and Gåsebäck. We have had the possibility, by cooperation with Helsingborg stad, to give a proposal how to project green roofs as a part of H+. We have also researched the amount of rainwater over a year in Helsingborg to investigate how much that can be absorbed by green roofs. Keywords: Green roof, sedum, Helsingborg