1730 House how to make Ceiling Level
1st off, make sure all structural elements are sound before closing. And it's a good idea to clean up the patchwork up there. It's actually very easy to level. Use a lazer level adjusted to your lowest point. Sister any joists to that line. This image shows how with T-bar drop ceilings but the concept is exactly the same.


This one shows how to do it using steel stud.