I pulled out the latest issue of Green Futures for a bit of light relief. It instantly lifted my mood as it reminded me just… how exciting sustainability issues can be.
Shanghai WinSun Decoration Design Engineering Company, based in Suzhou, China, has shown it is possible to construct 10 homes in one day, using a supersized three-dimensional (3D) printing rig.
According to footage and images published by the company, each building, measuring 200 square metres, was created in a few hours using recycled construction and industrial waste extruded through a giant nozzle as cement, layer by layer. A widely reported cost of less than USD 4,000 per house has not been confirmed.
Following a computer-aided design (CAD) architectural plan, the additive deposition process builds the main structure, leaving space for insulation materials, plumbing, electrical lining and windows, which are added later.
The concept proposed by Winsun is similar to a layered fabrication technology being commercialised by Contour Crafting, a spin-out from the University of Southern California (USC), based on a design by Dr Behrokh Khoshnevis, a professor of Industrial & Systems Engineering at USC.
However, whereas Winsun fabricates the building in parts, housing its 3D-printer rig in a factory, Contour Crafting has fully mobilised its technology so that it can build directly on the construction site. This localisation will be key to bringing the costs down, Khoshnevis observes: “Compared with prefabricated construction, 3D printing is not much cheaper, unless it can occur locally, onsite, eliminating costs of transporting materials and labour.”
By automating the construction of whole building structures as well as subcomponents, Contour Crafting aims to build houses, or colonies of houses, in less than 24 hours per dwelling. The technique, which uses the company’s proprietary cement to make structures and walls, eliminates labour costs, but also construction-related injuries and fatalities, claims Khoshnevis – although he would not give a cost estimate per house.
According to Khoshnevis, Contour Crafting is looking at various potential markets and opportunities, one of which is deployment in slum cities, such as India, China and parts of Africa, where there is need for low-cost, safe and structurally sound homes. The technique should be ready to roll-out in about one year, once the company can prove that its 3D-printed dwellings can meet building code standards in various target markets.
Photo credit: Contour Crafting/University of Southern California (USC)