Additive manufacturing in construction is beginning to move from an architect's modelling tool to delivering full-scale architectural components and elements of buildings such as walls and facades. This paper discusses large-scale additive manufacturing processes that have been applied in the construction and architecture arena and focuses on ‘Concrete Printing’, an automated extrusion based process. The wet properties of the material are critical to the success of manufacture and a number of new criteria have been developed to classify these process specific parameters. These criteria are introduced and key challenges that face construction scale additive manufacturing are presented. ► Built a full-scale of extrusion-based additive manufacturing (AM) machine for Freeform Construction. ► Developed a high performance concrete for Concrete Printing process. ► Created a variety of prototype parts, including the world's first reinforced concrete AM component — WonderBench.