Diagnosing Foundation Cracks


Shearing, hairline, wide, horizontal, vertical. What do all these words have in common? They are the types of cracks you may find in your foundation floor or basement walls. There are some cracks you don’t need to worry about, but more often than not, cracks are signs of foundation damage or shifting.

Hairline vs. Wide Cracks

Hairline cracks are very thin — not much wider than a hair’s width. They may be short or long, and a few of them may be the result of a new house settling. As long as there aren’t many hairline cracks and they aren’t long, you don’t need to start worrying. However, it’s still a good idea to get them filled, as they can widen if the foundation is not waterproof.
Wide cracks mean there has been significant shifting and water pressure against the concrete. You should have wide cracks filled as soon as possible to prevent future deterioration of the foundation floor and basement walls. Although concrete fillers are available at home improvement stores, it’s best to hire an expert when fixing a foundation.

Horizontal vs. Vertical

Hydrostatic pressure is lateral pressure that originates from the outside and pushes inward. This pressure causes horizontal cracking. It also can cause bowing of the walls; if bowing is present, call a specialist immediately. Vertical cracks are the type you see when the house initially settles and are the ones described above as hairline or wide.


Shearing cracks look like stair steps you might create on an old Etch-a-Sketch toy. They are obvious and may be on the inside or outside of the foundation. Put simply: shearing is not good. Like most cracks, shearing is a result of water saturation in the soil, shifting, and water pressure. If it’s not fixed, the shearing will get worse.

Garage Floor and Chimney Cracks

Any cracks in the outside of a chimney or along a garage floor usually mean there are drainage problems and the soil is expanding. If this is the case for these locations, it is the case for your home’s entire foundation. Unless you have a cracked pipe or water is being funneled to a specific location, soil saturation occurs throughout your full property. Some cracks in a garage floor may be because of improper installation or support-bar locations, but it’s best to get a professional assessment in case the issue is moisture.

Ceiling Cracks

Although not near the foundation, cracks in the ceiling can be indicative of foundation issues. Large ceiling cracks that look like spiderwebs mean you likely have structural foundation problems that have emanated upward through the home. Long vertical cracks that run from the ceiling and continue down the wall mean your home has shifted significantly and its support structure has moved.


A specialist should do all waterproofing and repairs related to fixing a foundation and making it dry. An expert can fill cracks properly, add support to basement walls, and lift the foundation floor. After the repairs have been made, discuss options for preventing future damage. Options may include a new drainage system, sump pumps, or a gutter system replacement.

Acculevel Seals Cracks

Fixing a foundation is not a weekend DIY project for a homeowner. To prevent future damage to your foundation and basement, hire a professional such as Acculevel. Our company has been in the business of foundation and basement repair and waterproofing since 1996. We love to help people’s homes stay dry and comfortable, as well as be safe for years to come. We don’t believe in unnecessary repairs or overcharging, so you can trust us to give you a fair, free in-home estimate. After our expert staff has finished filling any cracks, we’ll take the time to talk to you about what should be done to make your home the best it can be. If you live in the Midwest and are seeing cracks in your foundation, contact Acculevel at (866) 669-3349 or email [email protected].

Kelly Kater

Over her twenty year career, Kelly has worked in a wide variety of fields: secondary education, nursing, biology, elder care, the postal service, multicultural development, and academia. She has developed a skill for translating industry-specific jargon into everyday language. Her goal is to share the knowledge and experience of the Acculevel team with homeowners, in a way that is both engaging and informative.

    Stay In Touch

    Get Email Updates

    Sign up for email notifications about new articles.