Communication between disciplines in building and construction can be improved significantly by the proper use of Information and Communication Technology. For that reason, many research groups have been trying to achieve such improvement, especially by using Product Data Technology and STEP, and more recently the IAI Industry Foundation Classes. Unfortunately, the practical results of these efforts, in terms of tools that are used in practice, are still poor. The main reason for this seems to be that most research efforts have been too much top-down oriented, resulting in complex models and long-lasting developments. This paper presents an approach which tries to combine the sound ideas of Product Data Technology and STEP with a strong bottom up development strategy. The approach is based on Neutral Object Trees: hierarchical structures in which the objects that must be designed and built, are structured in a simple decomposition tree. The Neutral Object Tree approach has been used for the development of an Object Tree at the Dutch High Speed Railroad project, which is implemented in a PDM-system that is currently in use.