Long erection times on-site and project-specific design work, performed by consultants, generally accounts for a large part of correction and building costs in construction projects. In a typical Swedish housing project, the pre- and design phase accounts for about 10-12 % of the total costs. Due to a lack of standardized conceptualization procedures, much of the design work is reiterated in each project, and thus avoidable costs are incurred. In order to minimize these problems an open building system, called MFB, which exploits standardized technical solutions, design and construction processes for off-site prefabricated housing is under development. The MFB system developer will provide a process manual that describes, in detail, standardized design, construction, and erection processes. The open building system relies on close cooperation with local, often small to medium-sized, enterprises that can efficiently undertake “local” building projects. Here, we present and analyse a standard procedure for the pre-design-phase to incorporate in a MFB-process manual. The pre-design-phase of a MFB-building project was recorded and analysed in terms of efficiency. A detailed process map is presented, showing that 122 process steps were logged from the first contact with the client until the generation of the tender. By standardizing the pre-design-phase, the number of essential activities could be reduced by 47%. An improvement in time efficiency of the pre-design-phase with co-instantaneous generation of effective cost estimates should lead to lower building costs in general. Furthermore, by tightly standardizing and controlling the process, it should be possible to repeat projects (or many aspects of projects), without repeating much of the pre-design-phase, even if the actors change.