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. / Miljonprogrammet, byggnader som byggdes mellan 1965 - 1974, är än idag en stor del av det svenska bostadsbeståndet. Dessa byggnader står idag inför ett stort renoverings- och energieffektiviseringsbehov. Samtidigt som behovet av renovering ökar har också solceller ökat i popularitet. Det ökande renoveringsbehovet i kombination med den ökade populariteten av solceller har lett till att efterfrågan på huruvida det går att montera solcellsmoduler på befintliga byggnader har ökat. Syftet med denna studie är att undersöka vad det finns för problematik kring utredning och montering av solcellsmoduler på befintliga tak med hänsyn till byggstatik. Fokuset ligger på byggnader uppförda under miljonprogrammet och hur byggnaders takkonstruktion blir påverkad av den extra lasten som solcellspanel innebär. En fallstudie har utförts där hållfastheten för ett tak med en tidstypisk takkonstruktion för miljonprogrammet beräknas. En jämförelse mellan de karakteristiska lasterna enligt Europeiska konstruktionsregler respektive Svensk byggnorm har även utförts för att ge en bild av skillnader och likheter mellan normerna. Ett antal intervjuer har också utförts med olika parter inom byggbranschen för att få reda på vad de ser för potentiell problematik kring installation av solcellsmoduler. Resultatet från fallstudien visar att takkonstruktionen som utsätts för den nya lasten i form av solcellspaneler inte håller enligt Europeiska konstruktionsregler. I jämförelsen av normerna visar det sig att den största skillnaden mellan dem är att Europeiska konstruktionsregler har en betydligt högre karakteristisk snölast jämfört med Svensk byggnorm. Även vindlasten skiljer sig mellan normerna. Likhet finns i nyttig last och egentyngd mellan normerna, där finns ingen nämnvärd skillnad. Det går att dra slutsatsen att Europeiska konstruktionsregler generellt har högre karakteristiska laster än Svensk byggnorm.

In the construction sector today, there is a lot of discussion about material reuse tominimize the negative environmental impact. By reuse of precast concreteelements, significant amounts of CO2 emissions can be prevented. In order toreuse a concrete element for structural purposes in a building, the element need tobe assessed to ensure it can withstand the required loads. This report is based on a comparison of different building codes, it describes andcompares three selected building codes and their associated concrete standardsfrom different eras. The purpose of the report is to compare the results obtainedwhen designing predetermined concrete elements and components. The findingswill indicate whether it is possible to reuse concrete elements that were designedaccording to previous standards. The calculations will demonstrate bothsimilarities and, more importantly, differences in the design approaches of thebuilding codes and how they have evolved. An investigation concludes that by employing a chain of checks, it is possible todetermine if an existing component is reusable considering its load capacity. The differences in reinforcement content vary within approximately 0-25% infavor of the previous code, i.e. the older code requires more reinforcement.