Years ago in McAllen, Texas, an old abandoned 124,500-square-foot Walmart superstore was renovated and put to new use as the largest single-floor public library in the United States. Across America, many malls have emptied out and thousands of abandoned big box stores sit empty, including hundreds of former Walmarts. Some, though, are getting creative new leases on life, becoming community markets, indoor tracks, gaming spaces, museums and more.

In McAllen, aisles that used to divide shoppers have been adapted or replaced to serve the community. The old Walmart is packed with computer labs, public meeting spaces, a cafe, an art gallery, a used bookstore and more. In other small towns and suburbs around the United States, the generic promise of all-in-one convenience big box stores once offered is being realized in new and site-specific ways.
Designers at the research and development lab of KTGY Architecture + Planning in Los Angeles have particularly inspiring aspirations for old shopping centers: plug-and-play modular prefabs that subdivide big empty boxes into transitional housing for the homeless. This is not the first time architects and designers have attempted creative solutions to this pervasive problem, but it’s notably ambitious.

The firm’s Re-Habit project involves housing as well as support spaces and services fit into unused spaces in big boxes or individual shopping outlet stores like Sears and JCPenney. Self-supporting communal residences, wher...