Purpose: The purpose of this study is to create a plan of procedure for medium-sized construction companies that want to work with project development based on Swedish laws and regulations. The plan of procedure will document how these companies can start with ecologically sustainable housing projects in the initial stage of the construction process. The framing questions for the study is:  What legal requirements, regulations and general guidelines exist that relates to ecologically sustainable housing projects in Sweden?  What does the initial stage of the construction process look like and what processes and methodologies are used for housing projects?  How can a process for starting with ecologically sustainable housing projects based on the initial stage and its processes be designed and documented? Method: The research project contains a case study that used semi-structured interviews as well as a document study to answer the framing questions. The respondents come from three different companies and have been based on two different housing projects, which made it possible to create a generalizable result. Findings: The result of the study consists of a plan of procedure which includes processes, sub-processes, activities and decision points. The plan divides the activities into internal and external parties and is based on seven main topics that emerged during the document study. This plan of procedure can help support businesses that want to start new housing projects under project development. Implications: The study has given tools for business development to building dwellings as project development from Swedish regulations and legislations about ecological sustainability have been created and documented. A foundation, in form of a process map, to build upon for ecological sustainable dwelling project, for middlesized contractors has been created. Limitations: One limitation of the work is that many decisions to proceed with a project, the design and choice of installation system are based on financial aspects. Since the work has only focused on the ecological aspects, the economy has ended up outside the work, which means that when the results of the work are to be used, the economy must be weighed in separately. Decision-making is also not based solely on current legislation, which the work has focused on.