By the late 2010s, it was clear to Kaja Kühl and Jay Tsai that they needed more space. As their daughter grew from infant to toddler, their one-bedroom apartment in Fort Greene, Brooklyn, seemed to shrink.
The most appealing move, they thought, would be to buy a townhouse where they could spread out, including with some outdoor space, and have more control in creating an energy efficient home. But they found that most townhouses were priced beyond their reach.
“We noticed that the kinds of places that were in our budget tended to be not brownstones,” said Ms. Kühl, 55, “but the slightly older, wood-frame-on-a-brick-basement houses that were often in not such great shape.”
Ms. Kühl, founder of the firm youarethecity and an instructor at the City College in New York and Columbia University, is deeply interested in sustainable building practices, and she saw advantages in the less popular homes. “I knew they were easier to insulate well because you can put insulation within the wood frame,” as well as behind the exterior siding, she said.
When she and Mr. Tsai, 62, a former financial adviser, found an ugly duckling townhouse in Prospect Heights, Brooklyn, they had their project. With a facade covered in vinyl siding and security grates, and an interior that had been sliced up into apartments, it needed a complete overhaul.
