Industrialization of construction is by some considered to be a solution to the building industry's problems about the lack of quality, high production costs, low productivity and poor environmental adaptation. Meanwhile, industrialized construction partly earned a bad reputation after the million housing program. As large-scale projects where promoted during this period, it worked very well to use the technique of construction elements. In the mid seventies though, criticism arose which claimed that the aesthetic qualities had been deprived in the corporates effort to make housing production as efficient as possible. Tyréns, Derome and CBBT (centre for building and housing in wood) cooperates in a development project to develop a building system for 4-8-storey buildings, consisting of three platforms: a technology platform, an IT platform and a processing platform. The technology platform consists of flexible, industrially built flat modules of wood and from this platform the subsystem stairwells, is broken out. The purpose of this thesis is to find an approach to analyze the demands and requirements in the development of stairwells and the goal is then to develop and construct a modular stairwell that meet current requirements and standards, and which solution can be easily integrated with existing building systems. The requirements and wishes have been compiled through literature studies, through the study of the building system, and through interviews with the developers of the building system and suppliers of stairs and elevators. The requirements are then compiled with the help of a simplified variant of the QFD method. The requirements have also been grouped according to whether they apply layout, all modules, walls or ceilings. After the compilation of requirements, new modules for the stairwell was developed. This work has been carried out by developing the existing modules of the construction system. It has brought several advantages. Among other things, as follows: • The number of modules in the build system has been brought down. • It has been easy to see to, that there are functional interface to other modules in the build system. • The new modules have the same manufacturing processes and the same fitting as the other modules in the build system. Calculations have also been made to verify allowable loads in terms of deflections and joints and to check that the fire requirements are met.