This article was originally featured on our sister site ARCHITECT.
Ice architecture—think frozen hotels, igloos, and winter festivals—seems quite the novelty in the context of a hotter planet. And yet, as another polar vortex descends upon Minnesota, I am reminded that climate change is more global weirding than warming, bringing extremely low winter temperatures to regions such as our middle-northern U.S. Such climate volatility has not deterred global interest in Arctic exploration for oil and other resources and expanding development in high latitudes raises the prospect of more year-round activities above the Arctic Circle. So is it time to get more serious about ice architecture?
Though there are four standard types of reinforced ice construction, researchers from hydraulic engineering research company B. E. Vedeneev VNIIG, in St. Petersburg, Russia, and the Eindhoven University of Technology in the Netherlands, identify the igloo as the first and best known of these. Made from blocks of wind-blown snow for its insulating capabilities, this one-room building typology exhibits a catenoid section—constructed with an ideal size ratio between diameter and height— to mitigate structural tension as the material gradually compresses over time. The scientists recognize that the Inuit often employed lichen to strengthen igloo structures as well as to minimize creep.
The remaining three approaches are all more recent developments: ice roads, ice dams, and ice domes constructed using inflatable molds. Each type demonstrates a different ice composite technology. For example, U.S.S.R. engineers created reinforced ice roads using tree limbs during World War II, and researchers at Eindhoven University incorporated sawdust to create a reinforced-ice replica of the Sagrada Familia in 2015. The latter material example is called Pykrete, a composite developed in 1942 by a British military scientist who proposed the construction of aircraft carriers out of 86 percent ice and 14 percent sawdust. (Winston Churchill actually authorized the idea, although it was never realized.) Reinforced ice composites like Pykrete offer four benefits over plain ice structures: increased tensile strength, reduced creep rate, accelerated construction due to more ductile material behavior, and reduced weight due to less volume of required material.
Despite these advantages, building with ice composites requires hauling materials to locations that are devoid of forests. In such cases, ice-soil composites offer a potential solution. The authors divide these into two types based on the size of reinforcing particles: microscopic and macroscopic. Microscopic composites made with fine sand or gravel exhibit homogeneous compositions, whereas macroscopic versions employ larger, visually discernible particles in the mix. Scientists have identified these ice-soil composites as particularly beneficial for extraterrestrial construction on cold planets with water, as no additional resources would be needed. And according to a 1998 study, researchers asserted that a load-bearing structural material made from ice and fiberglass could be economically feasible. “An initial system would require about 70 tons of equipment and propellant be lifted into low Earth orbit,” writes researcher David Buehler.
Last year, an interdisciplinary team won first prize at the New York Maker Faire for their proposal for a Mars Ice House. A joint effort by New York-based firms Space Exploration Architecture and Clouds Architecture Office, the project proposes the use of 3D ice printing on the red planet. Based on studies supporting the prevalence of water in a shallow ice table 20 centimeters to 1 meter below loose regolith, the team developed a process to convert ice into water vapor for deposition in liquid form. A mining robot called a WaSiBo would excavate subsurface ice via applied heat and pressure, piping the resulting water vapor to wall-climbing robots called iBo. Triple nozzles on these machines would deposit successive layers of water, reinforcing fiber, and insulating aerogel that would freeze instantly, creating translucent load-bearing walls. The team’s final design exhibits two nested structural shells—an interior structure containing elements critical for life-support, and an outer shell that delineates an inhabitable “front yard.”
Obviously, ice 3D printing need not be limited to extraterrestrial applications. McGill University architecture and engineering faculty developed an additive manufacturing process for ice object modeling with a research grant in 2006 while New York–based 3D printing marketplace and service Shapeways currently offers an Ice Sculpture Creator that uses desalinated water to create ice prints here on Earth. The printer’s maximum build size is limited to 56 centimeters in each dimension, or 176 cubic centimeters, and requires no supporting material. But in order to super-cool the water, the apparatus employs sodium acetate—a known skin and eye irritant. Once ice printing technology can be scaled up to produce building-sized components in subzero environments, however, this chemical additive may not be necessary.
Another promising strategy for digital fabrication in ice uses a subtractive, rather than additive, approach. Last year, Tokyo-based ad agency TBWAHakuhodo employed CNC milling to carve intricate ice cubes for Suntory Whisky. According to the International Business Times, each cube required six hours to produce using two drill bits—a thick one for rough shapes and a thin one for small details. The routers operated in a controlled environment chilled to 19.4 F. Like the Ice Sculpture Creator and McGill's computer-assisted ice construction, this approach produces diminutive objects for now, but one can readily imagine expanding this capability to produce larger ice objects and environments—perhaps even with currently available robotic technologies.
While new research in reinforced ice composite materials and computer-assisted fabrication promise expanded capabilities in ice construction, many challenges remain. One is the human preference for above-freezing interior temperatures. “The obvious problem with using ice is that it must be insulated from the warm temperatures inside the structure, at least for human and plant habitats, and it will probably require some type of active cooling such as cold gas circulating between the ice wall and the insulation,” Buehler writes. Furthermore, such a system would require significant reliability, as structural failure could be catastrophic. External temperatures similarly present a threat. The average summer temperature at the North Pole is 32 F, for example, meaning that highs are often above freezing. Thus, any serious ice building effort would be temporary in nature. Nevertheless, the prevalence of ice in polar regions, coupled with advances in ice fabrication technology, suggests that a compelling future for ice architecture awaits.