He did tawaaf on the roof of the Mas’aa (place of saa’i) because of the crowds
Question

                During the farewell tawaaf of Hajj, a man did tawaaf from the direction of the Mas’aa on the wall between the Mas’aa and the Mataaf (place of tawaaf) and in one of the circuits he did tawaaf on the Mas’aa. Is this valid or not? If it was not valid, what must he do?.
Praise be to Allah.Doing tawaaf on the roof of the Mas’aa is not permissible, because the Mas’aa is outside of the Sacred Mosque. Hence if a woman does tawaaf for ‘Umrah then gets her menses before doing saa’i, it is permissible for her to do saa’i because tahaarah (being pure) is not a condition of saa’i, and the Mas’aa is not a masjid so we cannot say that she cannot stay there. Similarly, if a woman comes with her family and she is menstruating, and she sits in the Mas’aa to wait for them as she is menstruating, there is nothing wrong with that. Similarly, one who is junub may stay there without doing wudoo’, because it is not a masjid. And the one who is observing i'tikaaf in the Sacred Mosque should not go out to the Mas’aa, because the Mas’aa is outside the mosque. It is not permissible to do tawaaf outside the mosque because Allaah says (interpretation of the meaning): “and circumambulate the Ancient House” [al-Hajj 22:29]. If someone circumambulates outside the boundaries of the mosque, then he has circumambulated the mosque, not the Ka’bah. But we think that nowadays with the large numbers of pilgrims and the severe crowding, that if a person does tawaaf on the roof of the mosque and the narrow space beside the Mas’aa becomes overcrowded and he finds no alternative but to go down to the Mas’aa or to do tawaaf on top of the wall, then in sha Allaah there is nothing wrong with that, but he should take the opportunity whenever he sees a gap to go back into the mosque. End quote.