The ecological performance of concrete, particularly of its constituent cement, can be endlessly debated, yet there is no alternative material which can compete with its universality and availability. This, however, does not imply that the concrete can´t become a sustainable and environmental material. The ideas of lean production suggest that a performance of a technology can always be improved through a thorough analysis and optimization, e.g. through a careful reformation of the way concrete is treated it should be possible to improve efficiency and durability, reduce its embodied energy and production waste. An illustration of such a decisive optimization can be found in the concept of Ice Formwork – an alternative fabrication approach studied at Royal Institute of Technology in Stockholm by Vasily Sitnikov. While proposing the use of ice as the molding material, this research pursues a development of a completely waste-free and energy efficient application of digital fabrication processes (such as CNC milling) for production of new types of precast concrete construction elements.