When Should You Worry About Foundation Cracks?

C.E. Larusso
Written by C.E. Larusso
Updated September 21, 2021
A white wooden house with a front porch
Phillip Spears/DigitalVision via Getty Images

A crack in the wall might be more than unsightly—it could spell big problems in your foundation

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First off, let us put your mind at ease: not all cracks spell bad news. Hairline cracks are common in newer constructions: the materials used to build your home will “settle,” or expand and contract over time, as humidity changes or soil shifts around. Shallow foundations are another reason your home might settle. You should always take care to patch hairline cracks with an epoxy sealant; if your home is less than two years old, your warranty may cover the repair costs—but don’t forget to take photos of the crack to submit with your claim.

If a crack seems to be getting larger, however, there might be a deeper issue afoot; keep an eye on it by marking where it begins and ends with a pencil. Then, check the length at least monthly to see how quickly it grows (if at all). If you hire a local foundation professional to check it out, they might use a tool called a crack monitor to track how quickly it grows. 

Here are a few more instances when it’s best to call in a pro.

1. The Cracks Are Horizontal

Horizontal cracks can indicate severe structural damage. Freeze-thaw cycles or hydrostatic pressure usually cause these cracks, which happen when water from rain or snow (as it melts) outside pushes against the foundation. Eventually, these cracks can cause walls to buckle and allow water to seep inside. If present in concrete, a professional will likely repair these kinds of cracks by slab jacking. 

In this process, holes are drilled in the slab and then a sealant is applied in the holes to raise the foundation to its optimal, original level. Slab jacking costs around $5 per foot of concrete that needs to be lifted; a 5-by-4-foot job would cost roughly $60.

There’s one exception to this rule, however. If the crack’s location is where the foundation wall meets the basement floor and is no wider than a half-inch, it should be sealed but is not likely a structural problem. Basement floors are poured after the walls, and the spots where the concrete comes together don’t always bond entirely.

2. The Cracks Run in a Stair-Step Pattern

A red brick house with intricate details and stairs leading to the front porch
PC Photography/iStock / Getty Images Plus via Getty Images

Cinder block or brick foundations might have cracking in a stair-step pattern, along the mortar joints. These cracks, which may be caused by bowing walls, can cause major problems for the structural integrity of your foundation and should be looked at by a professional.

3. The Cracks Are Wide

Cracks larger than a quarter-inch might be nothing, but they might also be something, especially if the wall on one side of the crack juts out more than the other. For wider cracks, it’s best to have a professional check them out to be safe rather than sorry. If the cracks are wide and there’s a bump in the foundation wall, there could be hydrostatic pressure on the wall—this is definitely cause for concern.

4. Water Is Leaking in the Crack

If the wall around the crack feels damp or you see water around the crack, you may have a water infiltration issue. You should first check the surface drain, and then see if the crack can be sealed with an epoxy resin. It’s also important to redirect the water away from your home so you don’t experience other kinds of damage from moisture. To do this, you might need to install gutters or place soil around the foundation in such a way that allows for an angle away from the home where water can run off.

What to Do If You Have a Worrisome Crack in Your Home

If the crack meets any of the criteria outlined above, we recommend hiring a local home inspector to evaluate the crack. Home inspector visits can range from $100 to $150, though some don’t charge for inspection alone. Structural engineers are more expensive, with base costs between $340 and $710 for an inspection.

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