Massive flooding severely damaged the rural town of Hamburg, Iowa, in 2019. But soon, some residents will have unusual new homes: Iowa State University (I.S.U.) plans to rebuild an entire neighborhood with 3-D printed houses. Designers at the school will use a giant 3-D printer that can dispense concrete, laying down layer after layer of what will eventually turn into walls. (Doors, windows, and a roof are added on afterward, making the end result look like any other traditionally built house.) The process can be completed in a matter of days with little manpower, saving a lot of money. Pete Evans, I.S.U. assistant professor of design, says this technology could help increase the amount of available affordable housing. And it does seem to be catching on: Last year, the first 3-D-printed home in the U.S. was listed for sale in Riverhead, New York, and other groups around the country have announced plans to create similar buildings. “The ability to deliver these projects so fast,” Evans told KCCI-TV, “is going to create a new way to think about housing.”