The small extension of a residential building in a Swiss suburb explores a new way of using fast re-growing building materials. Hemp is known as a plant that can be used in nearly unlimited ways. The plant can be used for medicine, oil, textiles, biofuel and as building material. The project uses hemp as insulation material, combined with wood, and flax resulting in an organic color and material palette. The result is a highly healthy space, minimizing the environmental impact with an outstanding thermal performance. The project also allows for temporary heat-storage within the walls while overcoming the preconceived limits of pure wood constructions that use traditional insulation materials.