The aggregate area of penthouses and other roof top structures shall not exceed:

• A. 10%
• B. 25%
• C. 33 1/3%
• D. 50%

Answer: (C)

Rooftop footprint rules limit how much space on the roof can be taken up by penthouses and other roof structures. The limit set is one third of the roof area, which is 33 1/3 percent. This balance lets essential rooftop elements exist without crowding the roof so much that drainage, access, safety, and maintenance become problematic. In concrete terms, if the roof area is 9,000 square feet, the combined area of penthouses and rooftop structures cannot exceed 3,000 square feet. The other percentages would constrain or expand the allowed area inconsistently with this standard, while 50% would overburden the roof and reduce usable/deck area and drainage space.