A 400-Square-Foot Apartment That’s Constantly Transforming

Once Michael Mance and Shannie Easterby adopted a child, it didn’t take long to realize that a 400-square-foot apartment wasn’t going to work for them anymore.

“It was a lovely little apartment,” said Dr. Mance, a clinical psychologist, of the one-bedroom co-op on the Upper East Side of Manhattan that they bought for about $300,000 in 2006. But when they added Bella, now 8, to the mix in 2015, it began to seem less ideal.

“Around the six-month mark, it just became obvious that we were not going to be able to sleep in the same room anymore,” Dr. Mance, 50, said. “We were keeping her awake, and then she was keeping us awake.”

The conventional solution would be to find a larger apartment with two bedrooms. But he and Ms. Easterby, 49, an occupational therapist, liked their little space, and the neighborhood, and wanted to stay put. And they didn’t like the thought of taking on a substantial mortgage.

So they began searching for a design solution to their problem. “We looked at a lot of different projects by a lot of different designers,” Dr. Mance said.