How much does it cost to repair a sagging floor and replace the subfloor?
On average nationwide, repairing a sagging floor costs between $1,000 and $10,000. The average hourly cost for floor repairs is between $75 and $125 for the labor alone. How much you pay will depend on what's causing the floor to sag, type of flooring (concrete, hardwood, etc.), and how many square feet of floor is involved.
Depending on the cause, fixing a sagging floor can be pricey because the floor itself probably isn't the problem. A sagging floor is almost always a sign of a structural problem and can be the first sign of a sinking foundation that will lead to more damage. In addition to foundation problems, termite infestations, wood rot, waterproofing problems, damaged floor joists or subfloors, and a slew of other types of structural damage can cause floors to sag and slope.
Homeowners with old houses more often have issues with sagging and uneven floors, as do homes that have been flooded or been infested by termites. This is an issue no homeowner wants to ignore. Before you hire a specialist to help, get an estimate on how much your floor repair costs will be.
What's in this cost guide?
The type of repair, and how much your floor repair costs will be, depend on what problem is causing uneven or sagging floors.
Below are common causes of sagging and uneven floors and the average national cost to fix them:
| Cause | Average national cost |
| Termites | $250 to $2,000, plus costs to repair the damage |
| Flooring improperly installed | $400 to $3,000 |
| Subfloor damaged | $1,000 to $1,500 |
| Joists or posts deteriorated | $2,000, or $150 per joist |
| Water damage | $2,000 to $6,000 |
| Foundation sinking | $2,400 to $10,000+ |
Termite damage
If you have a termite colony gnawing on your floor, it will cost between $250 and $2,000 to remove termites. The little critters can eat floor joists or subfloors, destroying the support structure beneath your floors. Pest control companies generally charge per linear foot or per cubic foot for an active infestation, as opposed to the per-square-foot cost for preventative treatments.
A Thumbtack pro specializing in pest control in Apopka, Florida, charges $1,200 to $1,500 to fumigate an average sized house for termites. Fixing termite damage might have an additional cost, depending on the extent of it.
Improperly installed flooring
The average national cost to repair flooring depends on the material. Vinyl floor repair costs average $200 while marble floors can cost $3,000 or more.
Flooring that's improperly installed can sag or become uneven over time. Fortunately, this is usually the easiest and cheapest sag to fix, because you just need to pay a pro to pull up and reinstall the flooring.
A Thumbtack pro specializing in floor repairs in Charlotte, North Carolina, charges $75 an hour for the labor in a floor repair. Materials cost extra.
Damaged subfloors
Repairs to subfloors cost an average of $35 a square foot, but you will also have to pay a pro to pull up the flooring and then put the flooring back down after subfloor repairs are made.
A damaged subfloor can be caused by water or termites. To inspect the subfloor and check the exact cause, a pro will need to remove the flooring.
Some pros will charge a flat rate. A Thumbtack pro with experience in subfloor repairs in Alexandria, Virginia, charges a flat labor fee of $175 for 50 square feet or more of floor repair, with an additional charge to remove hardwood floors that have been glued down.
Deteriorating floor joists or posts
Replacing joists costs around $100 to $300 for each new joist.
Floor joists and posts support the flooring, and damage to them is the most common cause of a sagging floor. Deteriorating floor joists, posts, or beams can be caused by termite infestation, water damage, or dry rot.
To check joists and diagnose the problem, a pro must pull up the flooring and the subfloor to see what shape they're in. Checking joists is easier if you have a basement or crawl space foundation, because the joists are exposed.
Water damage
Depending on exactly what needs to be repaired and the scale of the damage, the cost to fix a floor sagging from water damage can cost between $2,000 and $6,000.
Water from a leak, flooding, or waterproofing problems can rot subfloors, floors, and damage joists. This causes floors to sag. Repairs will involved drying out the wet area, getting rid of any mold, and then making repairs. You might also want to consider a dehumidifying solution to prevent future problems.
Foundation
Repairing a concrete foundation costs between $2,400 and $6,800 on average but can cost upwards of $10,000 if hydraulic lifts are needed to lift the house. Repairing a crawl space costs around $6,000 depending on the size and amount of structural damage.
Over time, the dirt your house sits atop can compact, causing the foundation to sink. If you have a crawl space foundation, which is common in the south, a sagging floor often means you have a structural problem with your floor joists or beams.
Foundation repairs are the most expensive reason for sagging floors in old houses. You'll need to hire a structural engineer or foundation specialist to jack up and level the house and then shore up your home with pilings, beams, or even put new footers on the foundation.
The person you need to hire to fix your sagging floor depends on the root cause of the problem. If you're not sure of the cause, it's a good idea to hire a structural engineer to diagnose the problem—ideally one who won't have any part in repairing the floors (since that can be a conflict of interest).
Once you have identified the problem, you'll probably want to hire a contractor or foundation specialist to make the repairs. If it turns out the problem is your floors were installed incorrectly or there are problems with the subfloor, you may need to hire a flooring company.
And if termites are involved, you'll need to hire a pest control expert.
The amount of time it takes to fix a sagging floor depends on what's causing the sag. If the foundation is the culprit, jacking it up and leveling it can take weeks. If your hardwood flooring wasn't installed correctly, it can take as little as a day to pull it up and put it back down correctly.
How can you hire a professional to repair a sagging floor?
Before you hire someone to repair a sagging floor:
Consider hiring a structural engineer to diagnose the problem so you know what kind of repairs you need done. Once the problem has been assessed, look for a licensed, qualified contractor or foundation repair company with experience in repairing sagging floors, removing termites, or whichever type of repair you need.
Look at past projects. Make sure the professional has experience repairing sagging floors.
Ask for a free estimate and breakdown of costs. Repairing a sagging floor can involve a lot of steps. When you receive an estimate of project costs, ask:
- If the quote includes the cost to clean up and haul away debris after the work is complete
- What the job will entail and how it will impact you. If termite fumigation is needed, you'll need to get out of the house for a day or more. And if your home's foundation needs to be lifted and leveled with jacks, the project will take weeks.
Repairing sagging floors can be a gigantic, headache-inducing project for homeowners, but with the right professional on your side, it doesn't have to be. Get started today and find a flooring specialist in your zip code on Thumbtack.
