Architect Jayna Cooper had never designed a house before, much less played general contractor, when she broke ground on her new home in the middle of Los Angeles in 2009. After a grueling four months of hands-on work—managing subcontractors, sourcing materials, driving the front loader—she moved in. With a façade made of corrugated sheet metal, Cooper walks us through her completed home and reveals what it took to make this $200-per-square-foot abode a reality.  Photo 4 of 13 in 131-Day House