Stair step concrete block walls often crack along their block lines. According to almost home stair step cracks in cinder block foundation walls usually found in unfinished basements are a result of soil settling beneath the center of the wall. Stair step cracks may also signify heaving.
One of the most common reasons footings move is water or moisture in the soil under the footing freezes expands and lifts the footing and foundation wall.
Stair step crack in basement wall. This occurs when a large amount of pressure from the soil is exerted on the foundation wall. If you only had the stair step cracks you could go ahead with your basement finish work because that type of crack is a normal sign of settling. Even if it has been stable for awhile it can no longer reliably support the load its supposed to. Stair step cracks may cause cracks in other walls above or a door to rub but they dont compromise the strength of the foundation.
These cracks may appear on exterior or interior walls including crawl spaces and basement walls. Footings can move for many reasons. If you notice a crack accompanied by infestation leaks or mold however youre going to want to have your wall assessed for structural deficits. This cracking is caused by earth pressure on the outside of the wall most likely due to a combination of wet soils and frost push if this building is in a freezing climate.
Stair step cracks are commonly associated with foundation issues. If the wall is greater than the resistance the wall offers the wall will bulge into the basement resulting in the formation of cracks. In some cases cracks may signal more serious issues such as a foundation problem. If you notice a stair step crack think of it in the same terms you would a diagonal crack.
If you have step cracks in your foundation walls youre probably dealing with foundation failure. In most cases you wont have to worry about the minor cracks that appear in your concrete block wall. Stair step patterned cracks many times are an indication the footing under the foundation wall is moving. You may also notice a related crack on the adjacent wall corner.
This is fixable in many cases but a professional should inspect it before you repair to ensure that the wall doesnt need to be rebuilt. Above we see a different type of step cracking or diagonal cracks in a concrete block wall as well as a horizontal crack a bit above mid wall height right side of the photo. Then you noticed them stretching out and walking up the seams in the cinder blocks then you probably noticed that the whole basement started to feel damp maybe smell a little musty. The foundation wall in this case will bulge outward.
However the horizontal crack that has bowed the wall inward is the sign of a severely weakened wall that can fail. If a vertical crack widens at the top or bottom the wall is either settling or gradually heaving which may present serious issues. Cracks in your basement walls are a warning sign of foundation damages they started off as small almost imperceptible cracks along the windows. In some cases the soil outside the foundation wall may not provide adequate support for the wall.
The gaps in the wall can run in different directions but one common crack is called a stair step where the crack follows the mortar at a diagonal spreading across many blocks. When the frost melts the wall drops.
