Anpassning av ByggaF till prefabricerade småhus med trästomme

Sammanfattning: In Sweden the authorities’ demands gets higher and higher concerning moisture safety in the building process. Nowadays all new constructions need special planning regarding moisture safety, according to Boverkets byggregler. To fulfil their demands regarding a moisture safe building process, Boverkets byggregler recommends a method called ByggaF. This is a method for including moisture safety in the entire building process. It includes several templates which can be used to document the work with moisture-safety. ByggaF also includes checklists that highlight what is most important to consider with regard to moisture safety during the different stages of the building process. The method is very general and applies to all kinds of construction. This constitutes a disadvantage when applied to prefabricated manufacturing of single family homes due to differences from general construction in the building process and building techniques. The purpose of this study is to adapt ByggaF into a modified method ByggaF-PST applicable to prefabricated manufacturing of single family homes with timber frame. The prefabricated manufacturing building process requires adjustments in ByggaF because the building process involves construction of modules and elements in a factory. For this reason ByggaF-PST includes a new stage: Factory production. Another difference with this building technique is that the client in most cases chooses a house from a catalogue. This means that the house already is more or less planned when the client gets involved in the project. For this reason there is an essential difference between the prefabricated and the general building process. This affects the activities, stages, and parties in the presented method ByggaF-PST. A case study of Eksjöhus was conducted in order to obtain the necessary information to perform the adjustments. Additionally a questionnaire was sent to seven different companies regarding moisture safety in their building process. Based on the information that was gathered, adjustments were made in ByggaF, both to the method and the documents included. The adjustments in ByggaF that were made regarded constructions, parties and stages that are relevant to prefabricated manufacturing of single family homes. In addition to these adjustments some parts have been added to the documents and the method. Among these changes a more detailed checklist for risk assessment was made. Other changes regard supplemented moisture safety demands and activities in the factory concerning moisture safety. The result of this study is ”ByggaF-PST”, which is a method to include moisture safety in the building process of prefabricated manufacturing of single family homes with timber frame. This is a method that includes all stages in the building process. In conclusion it is shown that it is possible to adjust ByggaF to prefabricated manufactured single family homes with timber frame. Although a number of changes must be made in ByggaF to achieve this. To optimize ByggaF-PST it requires further adjustments based on feedback from the industry. Keywords: ByggaF-PST, manufacturing of single family homes, moisture safety-planning, prefabrication, responsible engineer, moisture expert