The top floor of Gavin and Sheila Smith’s century-old Craftsman-style house in Seattle’s Queen Anne neighborhood was, by any measure, a lousy place to sleep and keep an office. “It was cold, it was dark, it was cramped, it was just barely functional,” Gavin says. So, in 2012, Gavin, an architect, set about transforming it into a light-filled suite that includes a master bedroom and bathroom and a versatile space where he and his family could work and play.

His first step was to remove a series of collar ties to create a cathedral ceiling, which added nearly two feet of headroom at the center. A brick chimney was demolished, and four skylights were installed. In the office, Gavin designed built-ins—cabinets, a pair of desks, and two daybeds where the couple’s sons, Emory and Oliver, like to read—that add a note of flexibility.

Construction wrapped in March 2014, after about six months. Now, Gavin says, “it’s somewhere you can actually enjoy being. There’s plenty of light, so it’s a good place to work or whatever you need to do. It’s 180 degrees from what it was before.”