The integration of phases in the construction process is an issue not payed much attention. Recently research shown that inter phase periods is a time when value for the project easily can decrease. Several reasons for this exists, among others contractual agreements, change in persons, etc. In a popular term this problem is often called “over the wall syndrome”. The manufacturing industry has worked with this for many years, in e.g. integrated product development, concurrent engineering, supply chain management, etc. Now the construction industry needs to focus more on these crucial inter-phase issues of the construction process. This research first identifies the problems theoretically, and looks into which framework to be used in understanding of the phase transition problem. This combined with data from interviews reveal 8 major issues in phase transition, which decrease the value of the project. Among others, lack of communication, too little involvement from the client, scare resources, and conflicting interest. Special emphasis is put on analyzing the transfer of knowledge from design to construction. There is evidence that this is especially critically, since communication through tender often is limited due to regulations. Therefore, contractors miss a large amount of non-operational information, and the client and his consulting engineers never mange to share their tacit knowledge of project preconditions.