The last owner of this proud Prospect Park West house had chopped it into chintzy B&B suites. Much of our focus went to restoring period details and replicating the original stone, woodwork, and stained glass. But we took a surgical approach to our insertions, carefully modifying rooms to suit a growing family. We also wove state-of-the-art building systems through the historic structure. New soapstone slabs and inlaid floors crisply contrast with old filigree in the handsome kitchen. A new outdoor stair connects the two roof decks.