While life as a family revolves around spending time together, it also necessitates moments of peace and quiet. So when a young couple with children bought a four-story brownstone in Brooklyn, New York, they asked their architect, Matthew Baird, to transform the entire third floor into a master suite. The Manhattan-based Baird did just that, changing the spare bedroom into a spalike bathroom where modern amenities complement historic flourishes.

Baird used the room’s inoperative fireplace as the focal point of the design, initially hoping to offer his clients the ability to wash up in front of a crackling blaze. But when the unit’s repair proved too complicated, the team opted to brick up the firebox, refurbish the surround with mosaic tiles, and add a Pietra Cardosa hearth. They placed a freestanding oval tub perpendicular to the fireplace, installing a bubblelike LED chandelier above the soaker to illuminate the space. Then they added a mirrored vanity with flush vertical LED strips to the tub’s left, flanking the trough sink with a pair of polished chrome taps.

A large double shower occupies the opposite side of the room, separated from the bath area by a frosted-glass partition. Two polished-­chrome mixers on the exposed-brick wall provide a vintage feel, while a Pietra Cardosa shower floor, pitched and extended up the wall’s base, echoes visual themes elsewhere in the room.

The design team retained many of the space’s original materials. For example, rather than replace the existing wood floors with marble (which “would have been a shame,” Baird says), they patched its damaged areas with matching salvaged heart pine, and then sanded and refinished the surface with water-­resistant polyurethane.

The overall result is a harmonious collage of contrasting textures in a space unconventionally large for a historic building. “The whole design became a dialogue between old and new,” says Baird of the effort. “It makes the space feel more like a living room,” a place you’d want to rest and linger.