Your home’s foundation provides structural integrity to the entire house, so possible damage is understandably distressing. Sometimes, foundation repairs may not be as expensive or complicated as you fear. The trick is knowing the difference between small problems and large ones. 

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. We’ll also cover what causes these issues, how to assess their severity, and when to seek professional help.

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Understanding Foundation Problems

Foundation problems can stem from various sources and may worsen over time if left unaddressed. 

What Causes Foundation Issues?

Several factors can lead to foundation problems, including the following:

• Erosion
• Extreme weather conditions
• Poor drainage around the home
• Severe, unaddressed plumbing leaks
• Soil composition and movement
• Tree roots

These elements can cause the soil beneath your home to shift, expand, or contract, putting stress on the foundation.

The Importance of Early Detection

Catching foundation issues early can save you significant time and money. Regular inspections and prompt attention to warning signs can help prevent minor problems from escalating into major structural concerns. For example, patching small cracks in a basement wall can prevent the need for expensive structural reinforcement down the road.

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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. Once or twice a year, walk around the perimeter of your home and closely examine your walls and what you can see of the foundation. 

Homeowners can use polystyrene foam or epoxy to fix hairline cracks that are narrower than 1/8 of an inch. However, wider cracks in concrete slabs and cinder block foundations can indicate a larger structural issue. Horizontal cracks or stair-step cracks in brick are generally more concerning than vertical cracks, but large vertical cracks can be a sign of problems, too.

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 doorframes 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. 

Once again, horizontal cracks are the more concerning type, but all cracks are worth examining. 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. Clay soil can absorb a great deal of water, swelling as it does so. Since Texas often experiences heavy rainfall followed by periods of drought, the expansion and contraction of the soil puts stress on a foundation. In these areas, soil amendment or extensive drainage systems may be necessary.

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. Foundation settling or sinking throws a house’s frame out of square, meaning that installed features may no longer fit together correctly with the walls. 

Small separation may be a normal result of moisture issues or poor cabinet installation. However, if the space grows or if the problem occurs in multiple locations, you should investigate the cause.

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. A cracked or compromised foundation often leaks water into subgrade areas of the home. Investigate these areas for other signs of moisture damage, such as staining, wood rot, mold, or mildew. 

Alternatively, these kinds of floor damage can be caused by pests such as termites or carpenter ants. You may need to replace or reinforce your floor joists if this is the case.

6. Uneven or Sloping Floors

If you ever feel like you’re walking downhill inside your house, it could be that one side of your home is actually lower than the other. Changes to soil density and moisture can cause foundation sinking, which in turn makes floors sag or slope. Baseboards may also start to gap.

Of course, some sagging and gapping are common in older homes as floor and baseboard materials age. However, if the unevenness appears suddenly or extends across large areas, the damage is likely extensive and needs to be inspected quickly.

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 respiratory problems when inhaled. If you smell mildew or notice other signs of high humidity but can’t identify where the water’s coming from, especially in conjunction with other signs on this list, get a foundation inspection.

8. Cracked or Warped Siding

Cracked or warped siding can indicate your home’s foundation is shifting unevenly, causing your siding to break. Just like with cabinets, siding may also separate from exterior walls. Perform an exterior visual check of your foundation and exterior walls 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 or severe cracks.

9. Sticking Doors and Windows

Doors and windows that don’t open or close easily can be a sign of excess humidity or of walls and floors shifting out of square. Both of these, of course, are signs of foundation problems. Check sticking windows and doors for mechanical problems such as loose hinges or wood expansion first.

A few stubborn windows and doors aren’t cause for alarm, and excess humidity isn’t a sure sign of foundation trouble. Once again, though, if they occur with other problems on this list, such as cracked walls, separated cabinets, and sloped floors, have your home inspected as soon as possible.

10. Drainage Problems

Standing water around a home’s perimeter or in the basement can be a major cause of foundation damage, so if you notice it, you should address it as soon as possible. If you catch it early enough, you may be able to avert problems by adjusting your landscaping and adding drainage. If the problem’s been around for a while, though, the damage may already be done.

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. Even if you don’t have foundation problems, you’ll make your home safer by fixing this potential hazard.

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

Walls can bow or bulge from age and structural design flaws, but bowing basement walls may be a sign of external pressure on your foundation. Wet, swelling soil can cause foundation walls to warp or potentially even break, so this is one sign that warrants an immediate inspection, even if you haven’t noticed other signs.

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DIY vs. Professional Foundation Repair

While you can address some minor foundation issues, most significant problems require professional expertise.

Minor Repairs You Can Handle Yourself

Homeowners can tackle some small-scale foundation repair and maintenance tasks, such as the following:

• Filling hairline cracks (less than 1/8 inch wide) with epoxy
• Improving drainage around the foundation
• Maintaining consistent soil moisture levels around the home
• Trimming trees near the foundation to prevent root damage

When To Call In the Experts

Professional help is necessary for:

• Any repair requiring specialized equipment or expertise
• Cracks wider than 1/4 inch
• Foundation settling or sinking
• Structural issues such as bowing walls or uneven floors
• Water intrusion problems

Attempting complex repairs without proper knowledge can lead to further damage and more expensive fixes down the line. We always recommend starting with a foundation inspection from a licensed structural engineer.

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Cost of Professional Foundation Repair

Most homeowners spend around $5,074 to repair a foundation, including an average of $600 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 $250–$800.
• Drainage improvements: Installing a drainage system to divert water away from the foundation costs anywhere from $800–$15,000 depending on the severity of the problem.
• Foundation lifting: Using hydraulic equipment to carefully lift the foundation back to its level position costs $20,000–$23,000.
• Foundation replacement: In rare cases, you’ll need to lift the whole house and replace the foundation, which can run from $20,000–$100,000.
• Reinforcement straps: Attaching steel or carbon fiber strips to straighten bowed foundation walls costs $4,000–$12,000 total and may require one strap every 5 feet.
• Slabjacking: Injecting grout under a concrete slab to lift and level it costs $500–$1,300.
• Underpinning: Installing piers beneath the foundation to stabilize and lift it back to its original position costs $1,000–$3,000 per pier.

Homeowners should treat all foundation issues seriously. As a general rule, you should not treat foundation repair 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 October 2024.

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Long-Term Consequences of Ignoring Foundation Problems

The cost of substantial foundation repairs is indeed high, but they’re worth it to protect the value of your home and the safety of those who live there. If you ignore the signs of foundation damage, you may run into one of the following consequences.

Structural Integrity Risks

Ignoring foundation problems can result in:

• Compromised structural stability of the entire home
• Difficulty selling the home in the future
• Increased repair costs as damage worsens
• Potential collapse in extreme cases

Addressing foundation issues promptly helps maintain your home’s structural integrity and value.

Health and Safety Concerns

Foundation problems can create these health and safety risks:

• Collapsing chimneys or falling cabinets
• Mold growth from persistent moisture issues
• Pest infestations in damaged areas
• Potential gas leaks from shifting utility connections

How Foundation Problems Affect Resale

Homes with foundation issues often:

• Attract fewer potential buyers
• May be ineligible for certain types of mortgages
• Sell for less than comparable homes without problems
• Stay on the market longer

Additionally, most states require sellers to disclose known foundation issues to potential buyers. Failing to disclose can lead to legal troubles and potential lawsuits. You’re better off being honest about the damage—or having it fixed yourself.

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Our Conclusion

Signs of foundation problems almost always warrant an inspection by a structural engineer who can determine the cause of the issue and recommend 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 and consulting with a qualified professional can help catch issues early.

Enter your zip code in the tool below to find foundation repair experts near you.

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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 shifting features 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 installing plants with deep roots 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 or your realtor for referrals and get at least three quotes before choosing a contractor.

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