This report was done on behalf of Uppsala municipality with the aim to investigate how much the CO2-equivalent emissions differ between different building systems during the construction phase, considering the different choice of material used in the frames. Several multi-family houses with different building systems were therefore studied and compared by using previous LCA from collected climate reports regarding each construction project. Different scenarios of the residential development in Uppsala until year 2050, including multi- and single-family houses, were further on brought forward.

The impact that the choice of material had on the climate was then studied by comparing the scenarios with the climate goals set up by Uppsala municipality regarding the construction sector. This was discussed in order to investigate whether Uppsala municipality would reach the climate goals or not.

The conclusion of the study is that the building systems with wooden frames in general release less CO2-equivalent emissions than the ones with concrete frames. One of the reasons for this is that the production of the materials has different amounts of waste and the fact that concrete consists of cement, which causes a lot of emissions during the production of the material.

Another part of the report was to investigate if climate improved concrete could decrease the CO2-equivalent emissions from building systems with concrete frames. This was done by doing a case-study, where parts of the concrete frame for one of the building systems were replaced, which resulted in a small decrease of the emissions. It is however, in a larger perspective, important to reduce the emissions as much as possible and there is still room to continue the improvement of concrete.