Some foundation cracks are serious, and some aren't. We call these structural and non-structural cracks. Structural cracks are caused by foundation movement and can, if they're not promptly repaired, eventually threaten a building's structural integrity.
Typically, these are harmless and can form days or weeks after a new foundation is installed. Hairline cracks are often a result of the concrete or mortar drying out as it cures. In older homes, hairline cracks can appear as a sign of concrete aging and are also not cause for alarm.
Here's how to know if a crack is structural: One of the easiest 'tells' for structural damage cracks is that they grow over time. A thin, non-structural crack can quickly become a structural foundation crack if it gets wider after several weeks or months.
Big cracks in your foundation might be a sign of a serious issue. It's best to call a professional to take a look and assess the work needed. However, smaller vertical cracks are common due to the shift and movement of your home's foundation —but they still need to be fixed as part of your regular home maintenance.
Stair-step cracks along mortar joints or through the actual brick are almost always a serious matter—especially if the wall is bulging or if the cracks are larger than ¼ an inch. If you notice stair-step cracks in your foundation walls, call a contractor at USS immediately for a free foundation estimate.
10) Structural Foundation Crack
Sure sign of a structural deficiency are horizontal cracks, and cracks wider than a 1/4 inch. Structural foundation cracks are normally the result of movement, whether it's caused by temperature changes, soil pressure or soil shrinkage.
Generally, cracks with a width of less than 0.3 mm are acceptable and do not affect the structure.
Size matters when evaluating concrete cracks. The National Association of Home Builders (NAHB) standard for cracks in interior slabs requires repairing cracks that exceed three-sixteenths inches wide or high (vertical displacement).
They're just unsightly. Differential settlement is the cause of most structural foundation cracks. You can start to worry when you see, Cracks that are wider than 1/10 inch.
Typically, larger cracks (those bigger than 15mm in width) are a cause for concern, as they could point to structural issues. You'll want to get these inspected by a structural engineer.
Horizontal cracks are much more dangerous than vertical cracks because they can quickly lead to total foundation failure. Even without total failure they will likely begin to cause serious damage to the walls of your home as multiple supports in one area will likely already be compromised.
Thus, cracking in concrete beams, columns, or walls that are subject to bending forces is to be expected and is quite normal. "Even with the best floor designs and proper construction, it is unrealistic to expect crack-free and curl-free floors.
Shrinkage: The most common type of cracking in concrete, especially early on, is shrinkage. Concrete is a mix of cement and water. As the concrete hardens, which is caused by the cement and water forming bonds, some of that water escapes through evaporation.
It can be heartbreaking, but sometimes your only real choice when dealing with foundation issues is to walk away. If the seller won't make repairs, the damage is too extensive or you can't wait for repairs to be completed, you may have no choice but to give up and find your next dream house.
There is no such thing as “normal” foundation cracks. All cracks are an indication something went wrong. While not “normal,” small cracks are considered non-structural because they don't pose a threat to the structural integrity of your home.
Diagonal cracks at the corner of a window or door opening are usually caused by concrete shrinkage and aren't an emergency. Initially, diagonal foundation cracks do not threaten the structural integrity of your home. However, as with any foundation crack, they can worsen over time.
It usually takes between two and three days to repair cracks in a foundation. However, the time frame may be greater if the scope of work is more complicated.
No matter what has caused the foundation to crack, or whether it is moving or static, the crack should be sealed.
Foundation settling cracks can be problematic, especially if the damage is extensive. In these cases, the affected foundation may need repairs. If you see your foundation pulling away from your house or property, call an expert immediately.
Diagonal cracks or those that look like a staircase going up a wall are more serious. These cracks could be a sign of structural movement or damage and should be investigated by a structural engineer.
In applications such as concrete slabs and residential foundation walls, cracking is inevitable and expected. As the surface of concrete dries, water evaporates from the spaces between particles. As this water dissipates, the particles move closer together, resulting in shrinkage of the concrete.
A crack in a slab of 1/8 inch or less is typically a normal shrinkage crack and not a cause for concern. If the crack is larger or growing larger (an “active” crack), or one side of the crack is higher than the other, then you may need to have the work reviewed by a structural engineer.
Ultrasonic testing of concrete is an effective way for quality assessment and uniformity, and crack depth estimation. The test procedure has been standardized as “Standard Test Method for Pulse Velocity through Concrete” (ASTM C 597, 2016).