Joon Yong Park, chief creative officer of design and digital agency Firstborn, and his wife, Arum Seo, say that designing and renovating together helps keep their marriage strong. They are now listing their revamped home at 108-110 Franklin St. in Tribeca for $9.75 million.

The couple tapped James Ramsey, founder of design firm RAAD, for the project.

Ramsey is best known for designing the Lowline, an underground park planned for downtown Manhattan.

The four-bedroom apartment is a combo of two lofts separated by a brick wall, which has been incorporated into the new 4,300-square-foot space. Inside the mortar were brick arches — each of which has since been fitted with custom black steel doors, leading to a series of rooms off a main living space.

The home also features an open kitchen and dining room, with the bedrooms in a separate wing. An elevator opens to a foyer with a concrete floor and an oversize daybed that leads to the main part of the home. The white oak wood floors and white walls add to the home’s clean, streamlined feel.

Park bought the two separate units, 4W and 4E, for $2.52 million each in 2015.

The listing brokers are Howard Margolis, Marie Espinal, and Jeff Adler of Douglas Elliman.

Public relations exec Gail Horowitz is listing her Chappaqua home, located at 47 Old Mill Road, for $899,000 — down from its original $999,000 asking price.

The four-bedroom, three-bathroom spread features an oversize family room with a fireplace, skylights, pine ceilings and French doors that lead to a the deck.