In the 1890s, Brooklyn firemen would use the 80-foot-tall turret of their firehouse to check on conditions all across the city. Today, the Brooklyn Fire Department Headquarters is an apartment building, with its 18 units classified as affordable housing.

Developer MDG Design + Construction and the nonprofit Pratt Area Community Council recently renovated the building at 365 Jay St., replicating the original exterior in painstaking detail, said Michael Rooney Jr., the developer’s vice president.

“We...