How to tell if a foundation crack is serious?

Author: Mr. Ray Schmitt Sr.  |  Last update: Friday, April 4, 2025

Hairline cracks can be easily fixed and are often cosmetic. There are dangerous cracks though. If they're horizontal or at a 45-degree angle, if they're more than an eighth of an inch wide, or if they're wider at one end than the other, it's important to get them checked out.

When should I worry about foundation cracks?

Cracks do become a problem when they're actively changing or shifting — especially if they're becoming wider as time goes on. If you see a crack that is wider than a quarter of an inch, you need to call an expert to make sure your foundation isn't failing.

How to tell if a foundation crack is structural?

Sure sign of a structural deficiency are horizontal cracks, and cracks wider than a 1/4 inch. Structural foundation cracks are normally the result of movement, whether it's caused by temperature changes, soil pressure or soil shrinkage. In this case, epoxy is the material of choice for repairing the crack.

What size crack is acceptable in a foundation?

In our CFA Standard, we specifically call out that the maximum allowable crack for a foundation wall width is 1/8 inch because water and dampproofing can easily span that width. Exterior Slabs: Average concrete shrinks about 0.06%, so unless there are control joints, cracking is inevitable.

What do bad foundation cracks look like?

Diagonal cracks may suggest uneven foundation settling. These cracks are often wider at one end and can signify serious structural issues, especially if accompanied by other symptoms such as sticking doors or windows.

What Kind of Foundation Cracks Are BAD??

Does homeowners insurance cover foundation issues?

Homeowners insurance generally pays for foundation repairs that result from covered events. However, if the cause of the damage isn't covered in your policy, repairs probably won't be either.

What do settlement cracks look like?

A 1/16-inch crack is quite common when a home starts to settle. These hairline cracks should be vertical and should be between 2-6 inches in length. Having horizontal and diagonal cracks of any size will indicate that you have more than just the “normal” settling.

How much does it cost to fix a foundation crack?

Foundation Cracks

In fact, as foundation repair costs run, cracks can be one of the least expensive things to repair as long as they don't impact the structure. An average foundation repair cost you can expect to pay is between $250-800 to repair a crack in the foundation of your house.

What do non-structural cracks look like?

Non-structural cracks are usually minor and do not pose a risk to the building's stability. These cracks are typically less than 1/8 inch wide and are often caused by concrete shrinkage during the curing process or minor settlement of the building over time.

How do you tell the difference between settling and foundation problems?

Vertical cracks are often less concerning and may result from normal settling. Horizontal or diagonal cracks, especially those wider than 1/8 inch, may indicate more serious problems. Multiple cracks or those that form a pattern (like stair-step cracks in brick walls) often signal foundation issues.

How to know if a crack is serious?

The cracks are wide

A crack is more serious when it's between five and 15 millimeters wide (0.5 to 1.5 centimeters, or up to half an inch) as the cause could be more serious than simply dried out plaster or a house that is settling.

Can a foundation crack be repaired from the inside?

If you have a basement leak both interior basement crack repair and exterior basement crack repair are viable methods of fixing your foundation cracks. In many instances repairing a crack from the inside will be the preferred option.

When should I be worried about concrete cracks?

Small, thin cracks usually won't cause any problems and are better left alone. However, if your new concrete develops cracks more than ⅛” wide, it's better to seal them off from water with a high-quality concrete caulk so they don't get worse. You can repair cracks yourself, or hire a professional to caulk the cracks.

Can you live with a cracked foundation?

Minor foundation problems, like small cracks, may not be an immediate cause for concern and don't impact the habitability of your home. But they do get worse over time, which leads to significant problems down the line. More severe foundation problems, like significant shifting or sinking, can be a safety risk.

How can you tell if a foundation crack is structural?

Here's how to know if a crack is structural: One of the easiest 'tells' for structural damage cracks is that they grow over time. A thin, non-structural crack can quickly become a structural foundation crack if it gets wider after several weeks or months.

When should you walk away from foundation problems?

Multiple failed repair attempts: If a home has a history of foundation issues and nothing's been a permanent fix, think about walking away. Severe structural compromise: If foundation issues have snowballed into other issues, the repairs may be too expensive and complex to handle.

How big of a foundation crack is bad?

Hairline cracks under 1/18 inches are normal, but if you spot larger or deeper cracks, call a pro immediately. Cracks exceeding 1/4 inches are a sign of more serious structural damage and should be handled by a foundation pro.

What is an acceptable crack in a concrete slab?

The following list of conditions may be considered to help determine the severity of various concrete cracks: Cracks smaller than 0.3 mm in width are generally not serious and of not structural impact. However, they should be monitored for any growth.

What kind of cracks show foundation issues?

Horizontal or jagged diagonal cracks are particularly concerning for homeowners. Horizontal cracks often indicate serious structural issues because they suggest the foundation is under significant pressure or stress. Jagged diagonals can also be problematic, as they may tell settlement or movement.

Does homeowners insurance cover foundation?

Generally, foundation cracks or settling aren't covered by your homeowners policy. Your home's foundation is protected under your policy's dwelling coverage, but only for certain perils/events.

How does a structural engineer check foundation?

During the Inspection

Over the course of about 90 minutes, the structural engineer will: Examine the exterior for signs of settling or cracking. Inspect interior walls, floors, and ceilings. Check crawl spaces or basements for moisture issues.

Is it worth buying a house with a cracked foundation?

While you may see potential in a property with foundation problems, there are circumstances where the wisest decision is to walk away. For instance, if the foundation issues are associated with a severe structural problem, such as a sinking or shifting house, the repairs can be quite complex and expensive.

What is an acceptable foundation settlement?

If your foundation is settling into the soil beneath it, experts consider anything more than 1 inch for every 20 feet as too much.

How do I know if the cracks in my house are serious?

The size and location of wall cracks are key factors to consider. Large cracks wider than 5 millimeters are a cause for concern, especially if they are diagonal, horizontal or above a door frame.

Who is responsible for settlement cracks?

Construction-related issues typically fall under the builder's responsibility, while cracks resulting from natural settlement or external factors often rest with the homeowner.

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