1. "When I put this thing up—I called it the tiger cage—it started to feel a little imposing,” says Sauer of the steel rods surrounding his coffee-sipping spot. The solution: swapping the horizontal metal bars for wooden ones. A suspended box below frames the four-foot-tall TV nook.

2. The cantilevered table folds out to seat six, ideal for Sauer who entertains often and—believe it or not—has hosted up to 14 people at once in the apartment.

3. Sauer is a big fan of wood. “You can do almost anything with it.” He repurposed Ikea pieces to custom build almost all of the shelves, cabinets, and trim. He incorporated plenty of white throughout to avoid that dungeony ’70s look that too much natural oak can channel.

4.The closet–slash–computer corner: Clothes hang from a rack beneath the shelf where Sauer works on his laptop. Above, a twin bed—lined with a bolster that extends it by 10 inches—sleeps two. “It’s tight but peaceful.”

5.An Eames chair, always in style, makes for a cozy spot to take in the street-level Queen Anne bustle. Steps to the bed serve as additional seating. “What I find amazing is how comfortable each little station is,” says Sauer, who’s six-foot-two.

6.The three-foot-deep tub, complete with a sitting perch, took 100 bags of concrete—and nearly a year—to build and seal, and is hardly noticeable thanks to a circular rug on top of the seamless translucent trapdoor. Sauer plans to spend the winter soaking in style.