We were promised 3D-printed houses over a year ago now. But aside from one research project-slash-canal house currently under construction in Amsterdam, the skyline remains sadly devoid of printed Möbius strip-styled buildings or spider's nest-type homes.
But Minnesota-based Andrey Rudenko already has a 3D-printed castle in his garden. Rudenko just finished his project after two years of tinkering with the idea of 3D printing homes, and while the castle is only a model (though still impressively large), it was successfully printed out of a hardy cement material. He intends to get started on a liveable two-storey house as soon as possible.
Rudenko told me he was inspired to work with 3D printers after working in the construction industry for 25 years and seeing little advancement in terms of the technology used. "I'm ready to print a [full size] house right now," said Rudenko. "But I'm trying to find a lot to build it." After putting a couple of years into developing his 3D printer and the cement material it uses, he's waiting for someone who wants the first 3D-printed house for themselves, and who can foot the bill for the construction costs.
In the meantime, the castle demonstrates what he can do. He was commissioned to make it as a kids' playhouse, and his printing project isn't limited to disney-esque designs. "I like contemporary design and I would like to do something more contemporary, but the castle is pretty nice and my neighbours like it," he said.
The neighbours were initially less receptive to the 3D-printer; even though it was a scaled-down version of Rudenko's full-scale printer, they didn't quite get what it was, asking him if it was some sort of antenna.
Rudenko built the printer himself based on RepRap designs. Unsurprisingly, the most challenging part was fixing up an extruder capable of pushing through building materials.
"It's really really difficult to extrude cement mix or concrete," he said. "It doesn't like to be extruded." He spent a year designing different extruders and eventually built one that worked. He then had to find the right recipe for the cement mix. "It was not easy," he concluded.
Like a regular printer on a larger scale, the extruder piles up the cement in layers; it looks a bit like a giant piping nozzle icing a cake. The cement dries, and presto: a stripy wall (or, in the case of the castle, a turret). Minnesota isn't necessarily the ideal environment for 3D printing this type of material—it dries better in the warm—but he reported that, despite some initial trepidation, they hardened just fine and the castle didn't buckle.
He wrote on his website that on the next attempt, he plans to print the whole building in one go.
"During nonstop printing the layers turn out very even; all defects and imperfections on the castle happened when I stopped and started the print," he explained.
Rudenko said he does have a method to do a roof, but doesn't yet see the need to 3D-print that part. He's currently redesigning the printer based on lessons learned from printing the castle. But the main challenge will likely be getting the customer, and the relevant building permits, to print an actual house.