1920’s 2 story brick home sagging down the middle.

[Dustin Trouten]

I am not sure if I should sister joists for both the 1st floor ceiling and then the second story floor or can I jack up just the 1st floor ceiling and take care of it that way. Its a hip roof with no walls in attic so it would only lift 1st floor ceiling, floor 2’s floor and walls and 2nd floor ceiling. Not worried about 2nd floor cracks in walls as they need fixed anyways. Any advice or knowledge passed would really be appreciated. Thanks!