How Much Does It Cost to Level a Wooden Floor and Repair Sagging Floors?
Common Causes of Sagging Floors
Understanding why your floor is sagging is the first step in finding the right solution. Here are some of the most common causes:
1. Foundation Settlement & Shifting
Over time, your home’s foundation may settle unevenly, causing sections of the floor to dip or slope. This often happens due to:
- Poor soil conditions (expansive clay or loose, eroding soil)
- Water damage weakening the soil under the foundation
- Aging or deteriorating foundation supports
2. Weak or Damaged Floor Joists
Floor joists provide structural support beneath your home. When they become damaged, rotted, or improperly installed, they can cause noticeable sagging. Common culprits include:
- Excess moisture leading to wood rot
- Pests, such as termites, weakening the wood
- Improper spacing or undersized joists failing to support the load
3. Soil Instability & Erosion
If the soil beneath your home shifts, erodes, or expands, it can impact the stability of your foundation, leading to uneven floors. Factors include:
- Heavy rain or poor drainage washing away soil
- Expansive clay soil shrinking and swelling
- Tree roots interfering with foundation stability
4. Excess Moisture & Water Damage
Water intrusion from leaking pipes, poor drainage, or flooding can cause wood rot, mold growth, and weakening of floor supports. Common sources include:
- Basement or crawl space moisture issues
- Leaky plumbing or roof damage
- Poor exterior drainage causing water pooling
5. Poor Construction or Aging Materials
Some homes, especially older ones, may have undersized floor joists, insufficient support beams, or poor construction techniques that contribute to sagging floors over time.
Signs You Have a Sagging Floor Problem
If you suspect your floors may be sinking, look for these common warning signs:
- ✅ Visible floor dips or uneven spots
- ✅ Cracks in drywall or tile flooring
- ✅ Gaps between baseboards and the floor
- ✅ Doors and windows sticking or misaligning
- ✅ Bouncy or soft spots when walking on the floor
These signs indicate that the problem is worsening and needs professional evaluation.
How Much Does It Cost to Fix a Sagging Floor?
If you’re wondering, the typical cost of sagging floor repair starts at $3,000 and can go up to $18,000, with the average repair cost around $6,200. Pricing varies based on damage severity, materials, and labor. Some repairs for sagging or sunken floors cost approximately $300 per linear foot.
💡 Pro Tip: Costs vary based on the severity of the damage, home size, and labor expenses in your area.
Don’t Wait to Fix Sagging Floors
Sagging floors are more than just a cosmetic issue—they can signal serious foundation or structural problems. Addressing the issue quickly can prevent further damage, safety hazards, and costly repairs.
If you’re experiencing sinking floors, contact a foundation repair expert today for an inspection and customized repair plan.
In this photo, the slab foundation has sunk, creating a gap between the floor and the baseboard.
Cost of Fixing Floor Sinking in House and Sagging Floors in Basements and Crawl Spaces
This may be stating the obvious, but all of the structural wood framing in your home is interconnected. This means that the problem may not be limited to your home’s sill plate or rotted wood beam. In our experience, we find that multiple parts of the flooring system are usually affected. The direction or type of sagging floor usually highlights the area of greatest concern, which is how we explore the types of repairs below.
There are multiple causes that account for your sagging floor, but you should know that water and humidity often play a role in a floor sinking in the house. When you are planning to make repairs to your wooden framing system, keep in mind these may not be the only costs to consider.
Water around a foundation can cause settling or sinking; if you suspect this is an issue, we have a detailed guide to foundation repairs for you. You may also need treatment for mold to restore good air quality to your home.
We often recommend installing a water drainage system to prevent the problem from recurring in the future. Acculevel provides homeowners with a whole-home solution: a repair plan that addresses both floor repair and the cause of the damage to the floor.
This photo was taken by an Acculevel project advisor; the access point is only 12 inches tall, so he was unable to conduct an inspection.
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If you have a crawl space under your home, you will need to check the access dimensions. People and repair equipment need at least 18 inches of clearance. We have more information on how to find and measure your crawl space access in another blog.
How Much Does it Cost to Repair a Damaged Sill Plate?
If your floor is sloping towards an outside wall, but your foundation has not moved, this indicates that your sill plate is damaged or compromised. The sill plate is the piece directly on top of your concrete foundation, and it has to be replaced if faulty. To replace the sill plate, jacks are installed to temporarily hold up the floor joists, until the damaged sill is removed and replaced. Costs for sill plate repairs are $100-$120 per linear foot.
Illustration of a typical structural wood framing system, courtesy of NCSU.
What to Expect for Floor Joist Repair Cost and Fixing Damaged Joists
Floor joist repair costs for sistering range from $12-$14 per foot. A full replacement can cost $5,000 to $20,000, depending on the size of your room and extent of the damage.
When your floor drops, dips, or slopes, it often means you need floor joist repair near you to address sagging floor joists. Because the ends of floor joists rest on the sill plate, water damage often spreads from the sill plate to the floor joists.
Another common issue—especially in older homes—is notched joists. Older homes often have updated plumbing or HVAC systems installed. Because these don’t fit comfortably (especially in crawl spaces!), a contractor will sometimes cut sections out of a floor joist to make room for new ductwork or pipes.
These notches weaken the joists and cause them to crack, split, or fail. Sagging or damaged floor joists need to be sistered to be repaired. When a joist is sistered, a healthy board is run parallel and attached to the faulty one, to transfer the load.
Wonder why we don’t recommend replacing floor joists? It’s because your subfloor is attached (often with both nails and glue) to the floor joists. If you remove a floor joist, you could damage your subfloor — possibly compromising or damaging the tile, carpeting or hardwood floors above it.
How Much Does it Cost to Repair a Band Board?
For the record: band boards, rim joists, and band joists are all different terms for the same flooring component. There’s no right or wrong term for it; this seems to be a regional variation of terms. (Like soda vs. pop, or sneakers vs. tennis shoes.)
Whatever you call them, they are the wooden pieces attached to the top of the sill plate facing the exterior of the home. Their job is to protect the ends of the floor joists and help support your home’s outside walls.
Like the sill plate, the band board is often exposed directly to the outside air. This increases the odds of it being damaged by humidity. But like the floor joists, rim joists are best repaired by sistering them.
This is because replacing a band board would require excavating around the perimeter of your house to access it. It’s faster, easier, and less invasive to add a supporting piece from the inside of the joist box. (The joist box is the open space between floor joists on top of the sill plate.) Sistering a band board costs $38-42 per foot.
This picture was taken by an Acculevel crew member after a routine installation. The rotting sill plate was replaced, and damaged joists have been sistered.
How Do You Repair a Center Beam?
Do you know what the most common complaint we receive from homeowners about sagging floors? The title of this section kind of gives that away, but the answer is, “the floor sags or slopes towards the middle of the home.”
If your floor is sagging in the center, this indicates that the main (or center) beam is failing in some way. This is why an in-home evaluation is so critical; there’s more than one way for a main beam to be failing.
Shims May Need to be Replaced
In some instances, a builder may have used a shim to even out a crooked support post. These are small pieces of lumber that have been wedged in between the support column and beam to reach level. Over time, these shims will compress, lowering the beam.
This photo was taken by an Acculevel project advisor during a free home assessment. This wooden shim has been flattened over time, lowering the beam.
Acculevel uses steel shims that will not compress and increase the surface of the bearing load. Installing or replacing shims costs $110 per column.
Support Columns May Be Compromised
There are support columns set under the center beam that help to hold it steady. The distance between these columns can vary, depending on the building codes at the time your house was constructed. If the columns have cracked or broken, they will need to be replaced using adjustable steel floor jacks.
We often see this happen in older homes that have undergone renovation. Modern furnishings like granite countertops or spa tubs weigh more than their earlier counterparts. These assets are excellent selling points for a home, but they can be too much weight for the original support columns to handle.
This picture was taken by an Acculevel crew member during a routine installation. An adjustable steel jack has been installed in a crawl space to support an existing beam.
How Much Does it Cost to Install Adjustable Floor Jacks?
If the columns are strained by the weight of your home, this is a fairly straightforward fix. It doesn’t matter if there are too few of them, if they’re too far apart, or if the wooden or concrete support itself is damaged. In any case, you will need to add or replace jacks to better divide the load and repair your uneven floors.
Steel jack installations cost between $515-630.
For repairs with adjustable steel jacks, please be aware that the floors will not immediately return to level. Jack adjustments are done in small increments over time; attempting to expedite this process can cause damage to your home and the finished floor. Our goal at Acculevel is to help people, and part of that is being honest and clear about expectations.
What Does it Cost to Replace A Center Beam?
If your home’s center beam has cracked, split, or failed entirely, the best option is to replace it with a steel beam. Much like replacing a rotted sill plate, jacks are used to function as a temporary framing system to support the home during repairs. Once the jacks are secured, the damaged wood is removed and replaced with steel. Center beam replacement costs are $245-$305 per foot, depending on the number (if any) of additional supports that are needed.
This photo was taken by an Acculevel team member after installing an additional main beam and jacks parallel to the originals.
Earlier, we discussed how sometimes renovations create too much stress for the support columns. These can also be a problem for the center beam. If that’s the case, the best repair method may be a secondary beam and jacks. Done properly, installing an additional structure at the point of the greatest strain can prevent structural damage throughout the home. The cost for a secondary support beam is $200-$230 per foot, again depending on the number of jacks that it requires.
Sagging Floor Repairs Can Be Convoluted
In the process of covering this topic, we’ve thrown a lot of terms about structural repairs at you. This is not done to confuse or overwhelm you but to provide a detailed and thorough examination of the possibilities. While the average repair cost for a sagging floor is $6200, there are a wide range of causes and multiple components to evaluate.
This is an area where even experienced DIY fans should defer to the judgment of an experienced and qualified foundation expert. We specifically do not recommend that homeowners try to replace rotted sill plates, rim joists, or main beams. These are load-bearing wood components that perform a critical function. They’re responsible for supporting the entire structure of your main floor, and even a partial collapse could be devastating for the safety of your home.
How Can I Find Help to Fix My Sagging Floors?
Find an experienced local foundation company, and make an appointment. Before you sign a contract for any service, you should always verify the company is reputable, insured, and accredited by the Better Business Bureau.
If you live in Indiana or the surrounding states, contact Acculevel. If you have noticed sloping or sagging floors, request a free in-home assessment. An experienced project advisor will evaluate your foundation and recommend the best course of action for you to keep your home strong and healthy for years to come.
You can also learn more about floor repair costs, waterproofing, mold treatment, and other foundation problems in our homeowner’s guide to crawl space repairs. (While it’s possible for a home with a basement to have structural floor issues, it’s predominantly an issue for crawl spaces.)
