Vindsombyggnader i flerbostadshus från början av 1900-talet
Sammanfattning: Abstract A current problem in Sweden is the housing shortage. Especially young people are affected since there is a lack of small apartments. One way to increase the amount of smaller apart- ments is to retrofit unused lofts. To facilitate this type of reconstructions the Swedish parlia- ment voted for a legislative change on the first of July 2014. The change says that no elevator needs to be installed if the apartments are smaller than 35 m2. The change of the law makes it easier for property owners to retrofit older lofts since they often lack elevators. The real estate company HSB Malmö has payed attention to this legisla- tive change and are now taking a closer look on rebuilding loft spaces in several of their real estates from the early 20th century. This work was made in collaboration with HSB Malmö and has therefore focused on the technical aspects and general regulatory requirements when retrofitting a loft in a building from the early 20th century. In order to investigate how lofts from this epoch of time look like a house built in 1929 and owned by HSB has been used as an object of comparison. The main focus in this report has been; to map the general regulatory requirements, look at the load bearing capacity of the roof structure, see if the energy use can be reduced and study the moisture safety after a retrofit. The main questions have been applied to two different alterna- tives of rebuilding. One way is to preserve the existing roof structure and the other one is to build a completely new roof structure. The questions have been answered through a literature study, modelling in computer programs and help from tutors. Most of the study has been made with help of three computer programs, IDA Ice, Ramanalys and WUFI. IDA Ice made it possible to calculate the prospective energy use for the two alternatives. Ramanalys was used, among other things, to see how much effect a retrofit has on the roof structure and which ele- ments was most affected. To study the moisture safety in the construction a computer program called WUFI was used. After completing the study a few conclusions can be made. When it comes to the first alterna- tive, to preserve the existing roof structure, the roof trusses need to be reinforced. In addition to that more investigations need to be made on how to manage the horizontal forces, and the floor structure needs to be surveyed since it will be exposed to larger forces. An important quality with the preserving alternative is that parts of the old structure can be visible. Howev- er, this limits the amount of insulation and consequently the energy savings. An other problem with the first alternative is the difficulty to get it air tight. The air tightness affects both the energy savings and moisture safety. To build a new roof structure allows the builder to decide much more from the beginning. Every roof truss can be analysed as a unit and therefore fewer studies have to be made on the global structure. In a new structure more investigations should be done on how to connect the old and the new structure. From an energy saving standpoint a new structure is to prefer since a thicker insulation layer can be obtained, consequently the energy savings for this alternative are bigger. The two largest downsides with the new structure are a smaller living floor space (almost 40 m2 less floor space) and a more critical construction from a moisture safety point of view.
HÄR KAN DU HÄMTA UPPSATSEN I FULLTEXT. (följ länken till nästa sida)