Vertical integration of supply chains has enabled industrialised house-building companies to develop and use product platforms. Constant changes in the external business environment, such as customer needs, legal requirements and demand fluctuations, continually compel companies to strategically align their product platforms with market position and offering accordingly. Achieving alignment is often hindered by a lack of understanding of the interplay between the external business environment, product platform, offering and market position. The knowledge on product platform alignment in this industry exists in the literature; however, a coherent description of product platform alignment is missing. The aim of this research was, therefore, to expand the knowledge on the strategic aspects of product platforms by describing product platform alignment in industrialised house building. Empirical data were collected in two Swedish companies producing timber-frame single-family houses. The developed model provides a coherent description of product platform alignment via five alignment modes that group interplays between product platform, business model and the external business environment, whereas identified challenges additionally enrich the description. Formalisation of the product platform knowledge and the changeability of manufacturing systems are identified as two main enablers of achieving product platform alignment.