The extension building of the Experimenta Science Center was erected in Heilbronn until 2019. The highly geometrically challenging building consists of five floors with a pentagonal layout, that are twisted against each other. The composite structure in steel and concrete is stabilised by a central concrete core from which Holorib composite floors span to the floor-high truss walls, which transfer the loads to the foundations in their intersections with each other. The following report explains the structural design and the planning implementation used to achieve an efficient construction workflow. Moreover, the workshop planning, fabrication and assembly are described from the company’s perspective.