A second staircase—highly unusual in most Brooklyn homes—not only allows renters to access their unit without disturbing the homeowners, but also provides space for storage. To convert the space back into a 2,100 square-foot one-family home, the homeowners simply have to remove a small demising wall on the second floor and demolish the rental kitchen—a job that can be executed over the course of a long weekend.  190+ Best Modern Staircase Ideas from Revitalization