The third-floor master bath, part of a new glass-and-copper addition that KUBE Architecture attached to the back of the house, had none of the kitchen's constraints. There were no historic details worth preserving in the privacy of the top floor, so Bloomberg wiped the canvas clean. The idea was to create something lightweight and lustrous as a counterpoint to the heavy masonry of the traditional row house.

Bloomberg designed a seamless rectangle of a room with interlocking forms and materials. She wrapped the walls in 9-inch-by-12-inch polished ceramic tiles. The slate floor folds up over the tub, and the shower floor slopes imperceptibly toward a commercial pool drain that runs alongside the tub. “We had to come up with solutions that are more commercial because we were doing everything so minimally,” Bloomberg says. The motorized translucent shades that descend from the ceiling are a commercial product she has used in offices, as are the large windows in 1-inch aluminum frames. As they do in the kitchen, the linear cherry-wood cabinet drawers and extruded-aluminum pulls guide the eye horizontally. Another sleek detail is the concrete countertop with an integral sink that slopes in one direction, toward a trough drain that was cast into it.

As thoroughly modern as the new bath is, it doesn't completely deny the house's history. Bloomberg marked the point where the old ends and the new begins, while treating it as one continuous space. The frameless shower door is the point at which the original house connects to the modern extension. A notch in the glass allows the mirror and countertop to slide through. On the other side, the counter-top becomes a shelf for soap and shaving supplies, and the mirror extends behind the showerhead, offering a handy place to shave.