Improved resource efficiency, in industry and throughout the product life cycle, is a challenge and potentially, integrated product and production platforms can act as support. The aim of this study is to explore the current state of the technical platform in two industrialized housebuilding (IHB) companies from a mixed product architecture perspective. The study is part of a collaboration also involving three manufacturing companies and one IT provider. The research is crossing borders by means of interactive research and transdisciplinary engineering, and more than 50 practitioners and 13 researchers with competences in product management, engineering design, computational engineering, software development, production development, testing, quality, sourcing, and project management have been involved. Product platforms have been introduced in IHB to better control mixed product architectures and allow mass customization. Commonly, there is a technical platform for product architecture management, and a process platform for production management. High customization levels have resulted in an increasing number of variants not efficiently utilizing the technical platform. The results show that strong clients have negative influence on the technical platform while offering multiple products may facilitate simpler management of the technical platform but makes it more difficult to make changes and improvements.