Solceller på miljonprogrammets tak. Håller det? : En studie i problematik kring solceller på tak med fokus på takkonstruktionen.

Sammanfattning: The Million Program, buildings built between 1965 - 1974, is still a large part of the Swedish housing stock. These buildings now face a major need for renovation and energy efficiency measures. At the same time as the need for renovation is increasing, photovoltaic systems have also grown in popularity. The growing renovation need in combination with the increased popularity of photovoltaic systems has led to increased interest for whether photovoltaic systems panels can be mounted on existing buildings. The purpose of this study is to examine the potential problems when investigating the conditions for and the mounting of photovoltaic systems on existing roofs with respect to building statics. The focus is on buildings built during the million program and how the roof structure of these buildings is affected by the extra load from photovoltaic systems panels. A case study was performed where the strength of a roof with a time-typical roof construction from the million program was computed. A comparison of the characteristic loads according to European design rules and Swedish building standards was also carried out to give a perspective on differences in the standards. A number of interviews were conducted with various parties within the construction industry on the problem of photovoltaic system panel installations. The result of the case study shows that the roof does not withstand the new load in form of photovoltaic system panels according to the European design rules. When comparing the norms, it turns out that the main difference between them is that European design rules have a significantly higher characteristic snow load compared to the Swedish building norm. It can be concluded that European design rules generally have higher characteristic loads than the Swedish building norm, which can make the installation of photovoltaic system panels on houses built according to Swedish building norm more difficult due to the fact that the expansion have to be calculated according to the European design rules. Another major problem when investigating if photovoltaic system panels can be installed on typical roofs from the million program era, is lack of as-built documentation.