For smaller areas of repair, you can reduce the size of the new floor joists by one size. If you have a 2-by-10 joist, you can use a 2-by-8, or if a 2-by-8 joist, use a 2-by-6.

Sistering every joist to create one level takes precision. All-new subflooring and flooring is a lot of material to purchase. Finally the fallout of adjusting the trim and stairs takes time and skill.