Rooftops are exempt [from tithes], even if they are in a courtyard which is liable. A gatehouse, a portico, and a gallery are like the courtyard [in which they are situated]; if [the courtyard] is liable [in tithes], they [too] are liable. And if it is exempt, they are exempt.

What [type of] courtyard is obligated in tithes? R' Yishmael says: A Tyrean courtyard, in which utensils are kept safe. R' Akiva says: Any [courtyard the gate of] which one [person] opens and one [person] locks is exempt [from tithes]. R' Nechemyah says: Any [courtyard] inside of which a person is not embarrassed to eat is obligated [in tithes]. R' Yose says: Any [courtyard] which one enters and no [resident] says [to him], “What are you looking for?” is exempt [from tithes].  R' Yehudah says: [Regarding] two courtyards, one [of which is] within the other, the inner [courtyard] is obligated [in tithes] and the outer one is exempt [from tithes].