“House on a House” Showcases New Digital Construction Methods

DFAB House at night. The house is built on top of the Next Evolution in Sustainable Tech building. (Image courtesy of Roman Keller/ ETH Zurich.)

DFAB House, a building that its creators call the world’s first inhabited “digital house,” has officially opened. The house was built with a variety of novel digital building techniques, including specialized robots and 3D printing.

"The path from the digital drawing board to an actual building has challenged both scientists and experts from industry,” said Empa CEO Gian-Luca Bona in the joint press release. “Through a constructive dialogue, something truly visionary can now be put into practice; hopefully, it will soon be used broadly in the construction industry.”

The building is located in a bit of an unusual spot: perched atop the NEST (Next Evolution in Sustainable Tech) building as an experiment in building and construction. The NEST is a three-floor central module that engineers can “dock” building modules onto, much like attaching different pieces to a LEGO brick. Owned by building companies Empa and Eawag, the building has hosted multiple building experiments over the years.

The latest one, docked on the building’s third-floor platform, is a three-story house created by robots and 3D printers, with “smart home” tech inside. The top two floors are largely made of timber, put in place by a new form of timber construction called Spatial Timber Assemblies. The assembly form uses robots and prefabricated pieces to lay complex timber frames.

To lay the complex geometry of the curved concrete wall, the building team used a process called Mesh Mould, which combined the formwork and reinforcement into a single robot-operated step. The concrete slab used for the design is also novel. According to the team, Smart Slab is the first concrete slab made with a 3D-printed formwork, which is designed to be lightweight. Finally, the In Situ Fabricator is a mobile construction robot that can “spit out” items needed for construction.

But the house’s digital smarts don’t end with the construction process. The team behind it says that inhabitants have the benefits of smart blinds, burglar detection and household appliances, along with green energy to power it all. Photovoltaic modules on the structure’s roof supply approximately 1.5 times as much electricity as the inhabitants need; heat from waste water is recovered directly in the shower trays via heat exchangers; and hot water flows back into the boilers when it’s not being used, so it doesn’t cool in the pipes. The house’s first “guests,” academic residents invited by Empa and Eawag, will be moving in within about two months.

"The architectural potential of digital fabrication technologies is immense," Swiss project concept architect Matthias Kohler said in the house’s press release. "With the DFAB House, we are able to test new technologies hand in hand with industry and thus accelerate the transfer from research to practice."