Sagging floor and joist support
Floors that dip, bounce or slope are usually a crawl space problem. Here's what causes it and how it's fixed.
In a crawl space home, the floor rests on joists, which rest on beams (girders), which rest on piers and the foundation walls. When any part of that chain weakens or settles, you feel it upstairs as a soft spot, a dip or a floor that's out of level.
Common causes in Pitt County homes
- Moisture damage. Years of damp air can weaken joists, sill plates and subfloor, especially near plumbing and around the edges.
- Piers spaced too far apart or beams that are undersized for the span, common in older houses.
- Settling piers or footings. Some Pitt County soils are wet for long periods, and the county's soil data lists several series with high shrink-swell potential.
- Past alterations. Cut joists from old plumbing or HVAC work, or heavy loads added above.
- Insects. Termites and wood-boring beetles can do damage that isn't obvious until the floor moves.
How is it fixed?
- Supplemental piers or adjustable supports under beams to shorten spans
- Sistering new lumber alongside damaged or undersized joists
- Adding or replacing a beam under a sagging section
- Replacing rotted sill plates or subfloor
Floors that have sagged for years are usually raised gradually. Lifting too fast can crack drywall and tile. Fixing the moisture that caused the damage is part of the job, or the new wood will face the same conditions.
Permits and engineering
Structural repairs generally need a building permit from the city, town or county that covers your address, and some jobs call for an engineer's design. North Carolina also requires a licensed general contractor for projects costing $40,000 or more. Ask the company what your job needs.
Warning signs
- Soft or bouncy spots in the floor
- Doors that stick or swing open on their own
- Gaps between baseboards and the floor
- Cracks in tile or drywall above doorways
The crawl space company prices the job after getting under the house and measuring. We don't quote prices, and any number given over the phone before an inspection is only a rough starting point.
Where we connect you with help
Common questions
Can sagging floors be fixed from the crawl space?
Usually, yes. Most floor support work is done from underneath by adding piers, beams or sistered joists, without tearing up the floor.
Do I need an engineer for floor support?
Not always. Some jobs follow standard construction practice, while others need an engineered design. The company and your local inspections office can tell you.
Related services
- Encapsulation and vapor barriers
- Crawl space dehumidifiers
- Damp and musty crawl spaces
- Crawl space drainage and sump pumps
More background: Greenville, NC crawl space guide.
Musty smell, damp insulation or a soft, bouncy floor?
Call now and a local crawl space company will help you figure out what's going on under the house.