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13 Possible Signs of a Bad Foundation (2024 Guide)

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Default Author Icon Written by Angela Bunt + 1 other Reviewer Icon Reviewed by Mark Howey Updated 03/20/2024

Your home’s foundation provides structural integrity to the entire house, so possible damage is understandably distressing. Thankfully, foundation repairs may not be as expensive or complicated as you may think. This article explores the signs of a bad foundation and how to manage issues such as large foundation cracks, interior wall cracks, leaking basements, and more.

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Foundation Crack Repair

Foundation crack repair costs between $250 and $800.

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Side of house with serious foundation damage.
Foundation Leak Repair

Depending on severity, leak repair can range from $2,300–$7,300.

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Sinking concrete foundation in need of mudjacking leveling repai
Sinking Foundation Repair

The average cost for sinking foundation repair ranges from $600–$3,000.

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What Are the Signs of a Bad Foundation?

Below are 13 signs of foundation issues to be aware of—spotting these early can help ensure a cost-effective and reliable repair.

1. Exterior Wall Cracks

Exterior wall cracks are a sign that soil or a tree is putting pressure on your foundation or that your house’s foundation is sinking. It’s best to routinely inspect your foundation for minor cracks since even these could lead to water intrusion and possible damage.

Homeowners can use polystyrene foam or epoxy to fix foundation cracks that are narrower than 1/8 of an inch, such as hairline cracks. Wider cracks in concrete slabs and cinder block foundations can indicate a larger structural issue.


2. Interior Wall or Floor Cracks

Interior wall and floor cracks are often the result of normal house movement but could also be caused by foundation shifts. They often appear around door frames and windows. Cracks are of greater concern if they’re wider than 1/4 inch, if many suddenly appear, or if you see them in conjunction with signs of water damage. Schedule an inspection if you notice diagonal cracks extending away from windows or doors, as this could indicate serious foundation shifts.


3. Gaps Between Exterior Windows and Walls

Foundation issues, water intrusion, and thermal expansion and contraction can cause gaps to form between exterior windows and walls. However, gaps that are between 1/4 and 1/2 of an inch can indicate deeper structural problems and warrant an inspection from a structural engineer. This is especially true in areas with clay soil or black soil, such as Texas—the state with the most home foundation issues in the United States.


4. Cabinets or Countertops Separated From Walls

We recommend scheduling a foundation inspection if you notice considerable space growing between your cabinets or countertops and the wall. This can indicate damage from soil compaction or a settling foundation. Small separation may be a normal movement, but growing space should be investigated. Poor cabinet installation and moisture issues can also be responsible for separation.


5. Squeaking, Sagging, or Bouncing Floors

Squeaking, sagging, or bouncing floors aren’t always signs of foundation issues, but they can indicate that moisture has invaded your basement or crawl space. Investigation into whether the wood movement is construction-related or due to undetected deterioration is important. Issues can also result from wood rot or pests such as carpenter ants, which tunnel through wood. Alternatively, they can signal you need to reinforce or replace your floor joists.


6. One Side of the Home Is Lower Than the Other

If you notice your cabinets or countertops separating from the walls, sagging or slanted floors, or a feeling that the house has lost its level, you may be dealing with unstable soil. Any amount of sinking can be a risk to your house’s structure, so it’s best to address these issues immediately.


7. Mold or Mildew Smell

A musty smell in areas such as basements and crawl spaces is a telltale sign of mold, which develops due to excess moisture in your home. Mold and mildew aren’t always caused by foundation issues, but any excess moisture can lead to wood rot that damages your home’s structure. Mold and mildew also attract pests, such as termites, and can create health problems when inhaled. Get a home inspection if you notice signs of mold.


8. Cracked or Warped Siding

Cracked or warped siding can indicate your home’s foundation is shifting unevenly, causing your siding to break. Perform an exterior visual check of your foundation if you suspect something is wrong, making note of any areas where the siding looks uneven, warped, or visibly cracked. Cracked siding can allow moisture into your home’s foundation and indicate excessive shifting that may worsen over time, so get a professional inspection if you notice multiple cracks.


9. Sticking Doors

A sticking door could be the result of excess humidity that stems from wet crawl spaces or inadequate moisture control in your home. Doors can also occasionally stick because of loose hinges or wood expansion. A door that sticks because of a sinking foundation will come coupled with issues such as sagging floors, cracked drywall, or cabinet and countertop separation. Schedule an inspection to find the cause.


10. Drainage Problems

Landscaping around foundations should always slope away from the home to encourage proper water drainage. If you notice water pooling around your foundation or in your yard or basement, you may be dealing with drainage or waterproofing issues. Improper drainage can lead to serious issues with your foundation and basement, so act quickly if you suspect there’s an issue.

In the video below, landscape contractor Roger Cook shows a homeowner how to properly grade the soil around their home to prevent foundation damage. They also install a retaining wall and drainage system for added protection.


11. Leaning or Cracked Chimney

A leaning or cracked chimney is a sign of possible foundation issues and can indicate settling or sinking. A leaning chimney is potentially at risk of tumbling over, so schedule an inspection immediately if you notice cracks in the chimney’s bricks or the joints that connect the bricks.


12. Nails Coming Out of Drywall

When a drywall nail moves, the compound covering the nail head often pops off, exposing the nail head. A couple of nails doing this could be a sign of poor installation, but many coming out at once could mean that your foundation is shifting. Consult a professional if you suspect your drywall is moving, especially if nail exposure happens on more than one occasion.


13. Bowing Walls

Bowing walls might be from age, a signal that you have a structural design issue, or could indicate external pressure on your foundation. A foundation inspection should always be done if you note bowed walls.


How Much Does It Cost to Repair a Bad Foundation?

Most homeowners spend around $5,000 to repair a foundation, including $300–$800 for a structural engineer to inspect the home.* The exact cost depends heavily on the type and severity of the problem. For instance:

  • Crack filling: Filling cracks with epoxy or using polyurethane to seal them and prevent water infiltration costs $300–$800.
  • Underpinning: Installing piers beneath the foundation to stabilize and lift it back to its original position costs $1,000–$3,000 per pier.
  • Wall anchors: Anchoring the foundation walls to stable soil outside the house to counteract pressure and prevent further bowing costs $400–$700 per anchor.
  • Reinforcement straps: Attaching steel or carbon fiber strips to straighten bowed foundation walls costs $350–$1,000 per strap and may require one strap every 5 feet.
  • Foundation lifting: Using hydraulic equipment to carefully lift the foundation back to its level position costs $20,000–$23,000.
  • Slabjacking: Injecting grout under a concrete slab to lift and level it costs $500–$1,300.
  • Drainage improvements: Installing a drainage system to diverting water away from the foundation costs $2,800–$6,500.

Homeowners should treat all foundation issues seriously. As a general rule, foundation repair should not be treated as a do-it-yourself (DIY) project. The stakes are high, and the work can be complex and dangerous. There are a few exceptions, though. Small and inexpensive jobs, such as fixing a foundation crack with epoxy or polyurethane foam, might be manageable for homeowners.

*Cost data sourced from contractor estimates used by Angi, as updated in November 2023.


Our Conclusion

Signs of foundation problems almost always warrant an inspection by a structural engineer who can determine the cause of the issue and draft a repair for the problem.  Then you can get bids based on the report from licensed contractors with the expertise and machinery required to handle the task. Regularly checking spaces around your foundation can help catch issues early.

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FAQ About Bad Foundations

Is it safe to live in a home with a bad foundation?

It depends. Minor cracks might not pose an immediate danger, but major cracks, uneven floors, or bowed walls could indicate a dangerous structural issue. If your home has a bad foundation, consult a qualified foundation inspector to determine whether your home is safe.

How can I spot foundation problems early?

Visually inspecting your foundation for new cracks, large cracks, or diagonal cracks should be a part of every home’s yearly assessment. Keep an eye on any areas where moisture can enter, and note any strange shifts inside your house, such as cracked drywall or cabinets that separate from the walls. 

What can I do to prevent foundation problems?

Installing proper water drainage systems can help prevent foundation problems. You should also avoid planting root plants near the foundation, as this can disrupt the soil and cause pressure against your foundation. Ensure that areas such as basement walls and crawl spaces are adequately waterproofed to prevent moisture buildup, and regularly check your foundation for signs of issues.

How does a house foundation go bad?

A house foundation goes bad due to soil settlement, water pressure, or pressure from tree roots. Seismic waves, construction around foundations, and improper design or construction can also be reasons for foundation issues or failure.

Who should I hire to fix my foundation?

You should hire a licensed foundation repair specialist to fix your foundation. A structural engineer can assess the structural integrity of your foundation before and after repairs, but they will not perform the repairs. Ask fellow homeowners for referrals and get at least three quotes before choosing a contractor.

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