Ergonomics and spatial constraints are important issues to consider during the design process of limited spaces. In this paper, we present a user-centered methodology for designing a new VR tool for collaborative design and evaluation of limited spaces. The system is composed of two communicating tools: a sketch-based application, and a 3D immersive application. Using this tool, two collaborating users can perform simultaneously two steps of the design process: the sketching phase, and the organization and evaluation of the 3D space. A preliminary evaluation session, conducted with expert designers to assess the usability and the utility of the system, shows its value.