The cost of producing complex formwork or moulds for precast concrete and GRC (glass reinforced concrete) is perhaps the most significant limitation when constructing architectural intentions from prefabricated concrete elements. Our contribution, FreeFAB Wax , employs a 6-axis gantry robot with interchangeable end effector tooling to coarsely 3D print and subsequently mill finish complex moulds for concrete at a construction scale. Significantly, FreeFAB moulds can be up to 30m x 4m x 1.5m with significant time and cost savings relative to traditional formwork. Furthermore, FreeFAB's print material approaches 100% reusability, virtually eliminating waste and material costs within the process. This paper presents an overview of our method for construction scale 3D printing and its realisation. Our findings suggest a construction scale 3D printing is business-viable and significantly expands the feasibility of the wide spread use of bespoke moulds.