Sagging floor repairs are often necessary, and they tend to be simple and more affordable than most other home improvement projects and repairs. Prior to repairing the floor, it is necessary to determine the cause. Common causes are wood rot, undersized beams, or problems with the home’s foundation. Repairs that are often necessary to address a sagging floor include repairs to the foundation, floor joists, sill plate, band board and rim joist, center beam, support columns, and subfloor. Learn about causes of sagging floors and factors that impact the cost of repairs.