Key takeaways
- Floors sag when something below them is failing or missing.
- Moisture, termites and settling piers are common causes.
- Repairs usually happen from the crawl space with posts and beams.
- Gradual lifting protects finishes and plumbing.
Where sagging starts
The floor above a crawl space rests on joists, which rest on beams, which rest on piers and footings. A weakness anywhere in that chain shows up as a dip, a slope or a bounce in the floor above.
Dry-stacked block piers, wood posts and undersized beams are the most frequent culprits in older homes.
Common causes
Wood that has rotted from moisture, termite damage, soil that has settled or washed out under a pier and framing that was too light for its span are common. Sometimes a plumbing leak softens the subfloor.
In Middle Tennessee, clay that swells and shrinks with moisture can move footings over time.
How repairs work
We find what has failed, then add new footings and adjustable steel posts, sister damaged joists or replace a beam. Where the floor can be raised, it is done slowly, in small steps.
The moisture problem behind the damage is corrected so it does not return.
When to act
A floor that is slowly changing is a sign to schedule an inspection. A floor that suddenly drops, cracks or bounces badly needs prompt attention.
Mark levels with a pencil or take photos so you can show how things change.
Quick answers
Can I fix a sagging floor myself?
Adding a post can seem simple, but the footing, the load and the lift all matter. Professional help prevents damage.
Will the floor be level afterward?
Often much closer to level. Homes settle over time, and some movement is permanent.
Is a sagging floor a foundation problem?
Sometimes. It can be in the framing and supports or in the foundation itself, and an inspection tells which.
