Sagging floor support
A floor that dips or bounces is almost always telling you something about the crawl space. Here's what usually causes it and how it's fixed.
In a crawl space house, the subfloor sits on joists, the joists sit on beams, and the beams sit on piers and the foundation walls. A weak link anywhere in that chain shows up upstairs as a soft spot, a slope or a floor that shakes when someone walks across the room.
What causes it in Spartanburg County homes?
- Moisture and rot in joists and sill plates, especially near plumbing
- Long spans and wide pier spacing in older houses, including many mill-village homes
- Settling piers where footings are small or the soil around them stays wet
- Old alterations such as joists notched or cut for plumbing and ductwork
- Insect damage from termites or wood-boring beetles
Spartanburg County's comprehensive plan notes that some of the county's soils have foundation limitations from low load-bearing capacity, erodibility and steep slopes in places. That's one reason a crawl space company will look at the footings under the piers, not only the wood above them.
How is it fixed?
- Supplemental piers or adjustable steel supports to shorten beam spans
- Sistering new lumber to cracked, rotted or undersized joists
- A new or doubled beam under a sagging section
- New footings where existing piers have sunk
Floors that have settled over many years are raised slowly. Jacking too far too fast can crack plaster, drywall and tile. Expect the company to talk about fixing the moisture that weakened the wood, too.
Permits and engineering
Structural work may need a building permit from the City of Spartanburg, Spartanburg County or your town, and some jobs need an engineer's design. Jobs over $5,000 require a licensed residential builder under South Carolina law.
Warning signs
- A dip in the middle of a room or along a hallway
- Doors that drift open or won't latch
- Gaps opening under baseboards
- New cracks over door frames
Pricing is set by the crawl space company after someone has been under the house, measured it and seen what's wrong. We don't quote prices, and a figure given over the phone before an inspection is a guess at best.
Where we connect you with help
Common questions
Can a sagging floor be fixed from underneath?
In most cases, yes. Piers, beams and sistered joists are installed from the crawl space without pulling up finished flooring.
Will my old floor end up perfectly level?
Not always. Older homes are usually raised gradually, and a company may recommend stopping short of level to avoid cracking finishes. Ask what's realistic.
Related services
- Crawl space encapsulation
- Crawl space dehumidifiers
- Wood rot and moisture damage
- Crawl space drainage and sump pumps
More background: Spartanburg crawl space guide.
Musty smell, sweating ducts or a floor that's started to dip?
Call the number above and a local crawl space company will help you figure out what's happening under the house.