Should I be worried about a crack in my slab foundation?

Author: Dixie Howe  |  Last update: Tuesday, September 16, 2025

Vertical or diagonal cracking can sometimes indicate foundation settlement. However, other signs and symptoms of foundation problems would have to be present for this to be a concern. If there are no other signs around the home, then it's likely just a cosmetic imperfection.

How serious is a cracked slab foundation?

Foundation cracks may indicate a serious structural issue that requires professional evaluation and repair.

How do you know if a foundation crack is serious?

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 be concerned about slab 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. Cracks of greater width than 0.3 mm may present structural durability issues.

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 Kind of Foundation Cracks Are BAD??

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.

Does insurance cover foundation cracks?

Homeowners insurance typically doesn't cover wear and tear. Home foundations shift over time, which can lead to cracks in your home's structure. Like repainting a faded wall or clearing your gutters, keeping tabs on an aging foundation is considered the homeowner's responsibility.

How much does it cost to fix a cracked slab?

On average, the slab foundation repair cost ranges between $3,500-6,500. Prices for repairing severely cracked or sloping slabs can exceed $10,000.

What is an acceptable crack in a concrete slab?

Cracks that are identified as small and fine (less than 0.3 mm in width), are generally deemed acceptable as part of minor settlement depending on the purpose and intent of the concrete structure, the environment it is placed in, the design-life and the durability design.

How can you tell if a concrete crack is structural?

Some signs that may indicate that a crack is structural in nature may be that the crack is ⅛” or larger, a crack is horizontal in direction, the crack has shifted forward, one side of a crack projects out further than the other side of the crack, a wall is bowing, and there may be stair step cracks in the mortar ...

What foundation cracks are OK?

Some foundation cracks are normal and insignificant, such as small gaps that often occur due to the settling of a house over time. However, not all are normal; horizontal, vertical, or jagged diagonals, widening gaps, or accompanied by other signs like bowing walls or water intrusion are not normal.

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.

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.

What is the life expectancy of a slab foundation?

A foundation can maintain its integrity through timely repairs, soil compaction, and protection. For the average home, foundation should last about 80-100 years before needing to be replaced. But not repairing your foundation will make that number of years a lot smaller for your home.

Is a cracked slab a big deal?

Is a Crack in a Slab Foundation Bad? Cracks in a concrete slab can be signs of foundation issues, or they may just be superficial. Structural cracks in cement slab foundations can adversely affect various parts of the overlying structure.

Can you live in a house with a cracked foundation?

It is generally considered safe to continue living in a house with foundation problems. However, it depends on the severity of the issues.

Can a cracked concrete slab be repaired?

These fine surface cracks are often cosmetic and not signs of serious structural damage. If the rest of the concrete is sound and the surface is primarily smooth, repairing cracked concrete can be accomplished by applying a resurfacing product. This puts a thin repair layer over the cracks.

Can you pour concrete over a cracked slab?

If you notice any small cracks or minor issues, it's in your best interest to repair them before you pour the new concrete. Otherwise, your new concrete will have the same issues.

Is it normal for concrete foundations to crack?

Some cracks in the foundation, including hairline cracks, are considered normal foundation cracks. These typically appear due to settling or concrete shrinkage. Other types of foundation cracks might indicate a serious structural problem.

Is a cracked slab covered by insurance?

Homeowners insurance generally does not cover maintenance issues or wear and tear. So, if a slab leak results when tree roots damage your plumbing, or from plumbing lines that are simply past their prime, a typical homeowners insurance will not pay for repairs.

What is the most expensive foundation repair?

Depending on the type of issue, foundation repairs can cost as little as $250 for minor cracks and upwards of $25,000 or more if the issue requires hydraulic piers.

Can I sue for cracked concrete?

First, in general, a contractor is not liable unless there is a defect in the concrete and that defect arises as a result of a failure to follow the standard of care. As to the defects, surface cracks are not a defect in the concrete, but a natural occurrence because concrete shrinks as it dries.

How big of a crack in foundation is a problem?

Large cracks (also called major foundation cracks) are wider than a quarter-inch. These cracks continue to expand and are clear signs of a serious foundation issue.

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 happens if you don't fix a foundation crack?

Water damage.

If you use your basement for storage or living space, anything you keep there may be at risk if water is allowed to seep-in undeterred. Crumbling and cracking in a foundation can result in moisture penetration and the longer it goes on the greater the likelihood of significant water damage occurring.

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