What does that crack in my basement wall mean? Is my home still structurally sound? Or is this something to be expected in a house? Below, find explanations of common types of cracks and clues to look for that can help you to remedy issues.

What basement wall cracks mean:

Vertical cracks

As concrete shrinks during the curing process, vertical cracks form in the concrete or block, some so small they can hardly be seen. This generally does not affect the basement wall structurally, but could allow moisture to enter if the outside wall’s waterproofing isn’t flexible enough to span the crack. If moisture is seeping through, you might consider having a basement waterproofing contractor review the leakage. Often a concrete crack can be injected with a sealer to limit further moisture infiltration.

Basements may have hairline to 1/16 in wide vertical cracks. Prominent vertical cracks 1/8 in wide or larger could be a sign of distress that may need reviewing.

Horizontal Cracks

Sometimes a concrete or block basement wall will bow inward and develop a horizontal crack mid-height; this is where the wall feels the maximum stress from the force of the earth pushing against it. If the wall is plumb (straight up and down and not tilting inward), you can potentially monitor it to see if the size of the crack changes. If the crack continues to enlarge or the wall is out of plumb, a structural engineer’s review is recommended.

Diagonal cracks

There are several common types of diagonal cracks in basement walls. One of the most common is when the crack begins at the top of the concrete basement wall and moves diagonally down to a corner. This is usually accompanied with inward tilting of the top of the foundation wall. It can be caused by the earth pushing against the basement wall and an inadequate connection (i.e. missing anchor bolts) between the basement wall and the first floor framing.

Another type of diagonal crack can appear anywhere in the wall and is usually wider at the top and tighter at the bottom. This type of crack is usually caused by the foundation settling.

A third type of diagonal crack appears at the corner of a window or door opening. This can have several causes, but one of the most common is concrete shrinkage similar to that described in the vertical cracks section.

There is no quick rule for diagonal cracks or for your foundation wall tilting inward. If you are experiencing these in your basement walls, we recommend a review.

Stair stepping cracks in concrete block

Stair stepping cracks are very similar to diagonal cracks except stair stepping cracks occur in concrete block basement walls and diagonal cracks occur in concrete walls. Causes are similar to the diagonal crack issues listed above.

What cracks elsewhere mean:

Crawlspace foundation or garage foundation cracks

These spaces typically have more shallow depth foundations than basements and are more affected by soils that dry and shrink during extended dry summer weather. If there are interior cracks in the drywall or in the foundation wall that open in the summer and close in the winter, then the foundation wall might need additional support. A structural engineer can assess the situation and make recommendations.

Outside corner foundation cracks

Most houses with brick veneer have triangular shaped cracks on both sides of at least one corner of the foundation wall – occasionally the concrete corner will pop off. This is caused when the brick veneer expands and the concrete foundation below contracts, which is normal. Typically no engineer review is necessary for this situation.

Basement and garage slab cracks

When concrete cures (dries and hardens) it shrinks and wants to crack into relatively square sections; this is why you see control joints on sidewalks to provide weak spots where the concrete can crack without affecting the aesthetics, strength or safety.

Cracks may form with or without control joints. Tight cracks are not considered a structural problem. However, because basement and garage slabs are supported by the ground, ¼ in wide or larger cracks, vertical displacement at a crack line (the slab on one side of the crack line is higher than the other), or slab settlement can be a sign of a failure of the ground below and a review is recommended.

Now what?

Cracks may be harmless or may be an indication of a significant structural problem. It is important to pay attention to your home and monitor any changes to existing cracks or the development of new cracks in your basement walls. Schaefer cannot give engineering advice about how to evaluate a specific crack without reviewing a home’s basement wall first. While this blog may discuss general characteristics of cracks, all basement cracks potentially reveal a specific cause and related repair. A qualified structural engineer should be consulted for any crack that a homeowner is unsure about so a specific conclusion and recommendation plan can be developed. If you have concerns about a crack in your basement wall, schedule a structural engineer to review your basement walls; be sure the engineer has extensive experience with residential structures. Schaefer engineers are available to visit your home to determine the nature of your crack and to recommend corrective action if necessary.

To download a PDF version of this article, please click here.

Want more residential tips? Read Help! There are Gaps Between My Wood Trim & Floors!

37 Comments

  • My wife and I discovered a vertical crack about 20 inches high and less than a 1/16 of a inch wide on the drywall downstairs above the door way of two doors. What does that mean? Also both the doors ( where we discovered one of the cracks) are not closing properly. Is this an easy fix and is it something more serious

    • Reed, we would need to see the area before we officially comment on it, but normally if a door frame is racked out of square enough to affect the operation of a door, it usually means that something has moved or settled.

  • I would like to buy a house, nevertheless there are diagonal cracks crossing the basement floor. No cracks on the walls and floor is dry. Should I be worried?
    Thank you

    • Marcelo, unfortunately we cannot comment on your issue without seeing it. If you’re located near one of our offices (Cincinnati & Columbus, Ohio or Phoenix, Arizona), feel free to call us to discuss and schedule an appointment. Our number is 800.542.3302.

    • Garry, we’d be happy to answer your questions regarding your farmhouse. Please contact our residential home inspection leader, Jim Graham, by phone at 513.542.3300.

  • I’m looking to buy a house, it has a horizontal in the mortar joint spending almost the entire length of the wall. I’m afraid it won’t pass a VA HOME loan inspection

    • Gordie, unfortunately we cannot comment on your issue without seeing it. If you’re located near one of our offices (Cincinnati & Columbus, Ohio or Phoenix, Arizona), feel free to call us to discuss and schedule an appointment. Our number is 800.542.3302.

    • Carl, we would need to see the area before we could comment on it. If you’re located near Cincinnati or Columbus, Ohio, or Phoenix, Arizona, please call us at 800.542.3302. If not, you may want to find a residential structural engineer in your area.

  • I didn’t realize there was so much you could learn from different kinds of foundation cracks, especially the diagonal cracks and inward tilting of interior walls. If you do see these kinds of issues, it’s probably a good idea to have a professional take a look at them. That way, you can get a more accurate diagnosis and have repairs made to your foundation before the damages get worse than what they are.

    • You’re right, Bernard! It’s a good idea to contact a professional if you’re experiencing cracks and tilting.

  • Hello, we are trying to buy a house and upon inspection we discover a slight vertical crack from within the basement wall. the house is 8 years old. should this be major concern?

    Thank you

    • Kenny, we would need to see the area before we could comment on it. If you’re located near Cincinnati or Columbus, Ohio, or Phoenix, Arizona, please call us at 800.542.3302. If not, you may want to find a residential structural engineer in your area.

  • Hi, i ve just build a wall fence few week ago so now i am experiencing a vertical creck on a wall colums, what went wrong there because the wall is still new. Thanks

    • Concrete as a material normally cracks as it cures. The concrete shrinks, and small vertical cracks form in walls. If the cracks are vertical and less than 1/32 in wide, then they are probably shrinkage cracks. If the cracks are larger or they continue to grow, or if you are concerned about them then we recommend that you have a qualified structural engineer review them.

  • My husband and I recently looked at a home in Dry Ridge KY we are in love with the home but have some concerns with the cracks in the basement. What would the cost be for an inspector to tell us if the house has a good foundation?

    • Cost associated with a structural engineering review can vary. Please call us at 513.542.3300; after a quick conversation, we can schedule an engineer to meet you at the house, who will discuss possible alternatives for addressing any problem areas, and will provide a written report with observations, conclusions, and recommendations.

  • Hi, We have a couple vertical cracks in basement walls. We were told they could be fixed $600 a crack. We got other estimates one said he could guarantee not to leak $1500 a crack.
    Someone else wants to put inside french drain and fix all cracks for $6000.
    One crack use to leak but we put more soil and raised ground outside. Seems to have stopped but could get moist during storms. Nothing around other cracks.
    One guy said if we just fix crack a new crack will happen. Is that true? Home is 12 years old.
    we are located in south new jersey
    thanks

    • Thanks for reading! Unfortunately we cannot comment on your issue without seeing it, and New Jersey is outside of our reach for residential inspections. If you’re experiencing problems with your home, we recommend that you contact a structural engineer who specializes in residential applications near you.

  • I found a crack in my basement wall toward the the floor. When it rains I see water seeping through. Do you think this is an easy repair that I can do myself

  • WHAT NUMBER CAN I CALL IF I HAVE A CRACKS IN CINDERBLOCK IN MY CRAWSPACE. I HAVE A HOUSE IN SOUTH JERSEY. NEW JERSEY.

    • Hi Robert, New Jersey is outside of our reach for residential inspections. If you’re experiencing problems with your home, we recommend that you contact a structural engineer who specializes in residential applications near you.

  • I realized I have a diagonal crack in my basement wall. It goes from the top and goes down a bit more than half way down. It doesn’t have an alarming gap between, but I want to make sure if it’s something more than just settling to get it fixed right away so I can finish my basement and not have to worry about it. Any suggestions?

    • Hi Daniel – thanks for responding to our article. Diagonal cracks can many times be a sign of a deeper structural issue that requires further investigation and reinforcing of the foundation wall. We recommend that you have a local structural engineer familiar with residential foundations review your foundation wall and make recommendations. This work should all be done prior to any basement renovations. We hope this helps!

  • My one year old new house has a verifical crack at the foundation concrete. Size is about 1/16”. The crack is at the two wall joint area. My builder will have the structure engineer come to check. I believe the engineer will have an idea about the crack on the house structure. However, I am not sure whether the engineer is firm on water issue. Shall I worry on it? Thanks.

    • We recommend you go with the structural engineer’s recommendations. If the crack begins to leak, a structural engineer review it and make recommendations for having it sealed with an injected urethane foam.

  • Hi, my house foundation has been two years since the it was built. It was found a 1/16 size of vertical crack at the inner corner. The foundation has a waterproof membrane around. Shall I fix it or observe the crack change to decide the repaire? Greatly appreciate your suggestions.

    • You can monitor it and have a structural engineer review it if the size changes. If it leaks, have a structural engineer review it and make recommendations for having it sealed with an injected urethane foam.

  • we have a vertical crack in our storage wall. found when the floor was wet. it was probably there behind the insulation for a number of years without us knowing. it is a townhouse. this wall is towards the front of the house under the bay window. how can I send a pic of the wall ?

    • Jonathan – if you’re located near Cincinnati or Columbus, Ohio, or Phoenix, Arizona, please call us at 800.542.3302. If not, you may want to find a residential structural engineer in your area.

  • I am trying to match a custom stucco interior. It is full of cracks, some very pronounced and deep. Altogether it gives the place a very warm, old-world feel. It is a rough texture, appears to be quite thick and doesn’t seem to have any scratch or brown coat… just barrier paper over OSB, chicken wire lath and thick stucco.There are scores of articles on how to keep stucco from cracking… I want to find one which tells HOW TO get the stucco to crack.

  • My home is about 20 years old and recently , I noticed about 6 in vertical crack in the concrete foundation which is exposed above the ground and visible. The crack is about 1/4in wide. How can patch it up and is this serious?
    I can send a picture but don’t know how to link it to this section

    Don’t have a basement or crawl space in the house.

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