The foundation is one of the most concerning places for damage to occur because it can threaten the structural integrity of a home. Fortunately, not every imperfection you see in your foundation walls is cause for alarm. Here is an overview of three types of cracks in foundation walls and their possible causes.
1. Shrinkage Cracks
It may seem like foundations are made of inert materials, but they actually move a lot more than you would think. Concrete and masonry bricks continuously expand when they get hot and shrink when they cool as the weather changes. Poured concrete also experiences shrinkage due to chemical reactions that occur as it cures.
The issue with shrinkage in foundation walls is that the inside and outside of the material don’t shrink at the same rate. This creates shearing forces in the wall that build over time until cracks occur to relieve the pressure. These types of cracks are known as shrinkage cracks.
Shrinkage cracks are most often oriented vertically or diagonally, and they are usually hairline cracks that are uniform in width. Shrinkage cracks will sometimes start and stop along their path, making them appear like dotted lines. Fortunately, shrinkage cracks rarely reduce the load-bearing capability of foundation walls, but you should keep an eye on them to make sure they aren’t allowing moisture to leak into your basement.
2. Settlement Cracks
Nothing is more important for a successful foundation than the soil beneath it. Naturally soft soils, like those high in sand or clay, are prone to shifting under the weight of a foundation. This is also true for soil of any type if it is not properly compacted before the foundation is laid. All foundations will settle to some degree and may develop minor settlement cracks, but shifting soil can exaggerate these cracks and damage your foundation.
Settlement cracks are characteristically vertical cracks that are narrow at the bottom and wider at the top. This occurs because the separated sections of the wall bend outward from the crack. Multiple settlement cracks will often appear in the same segment of wall.
While settlement cracks do not guarantee structural damage on their own, you should check a few areas around your home to get a more complete picture and ensure your home is safe. Use a level to check for sloping floors, door frames, and window frames, and look over your walls for cracks in drywall, stone, or brick. These are clear signs that you should contact a home repair contractor for a professional assessment.
3. Stair Step Cracks
Stair step cracks are unique foundation wall cracks that are usually found along mortar joints in walls made of concrete blocks or masonry bricks. Since mortar joints are the path of least resistance in block walls, forces of any type can cause stair step cracks. The location of a stair step crack is the most important information to help you determine its cause.
Stair step cracks near corners are often the result of settling or thermal expansion in the middle of the adjacent wall. While the wall moves, the corners resist moving and create shear forces along the mortar joints. Stair step cracks below windows may indicate settling or soil shifting beneath the wall. Again, professional assessment is the best choice to determine the exact cause and the severity of the problem.
Understanding common types of cracks in foundation walls will give you peace of mind and help you recognize when there may be a serious problem. If you suspect that your foundation is in need of repair, don’t hesitate to call the experienced team at Du-West!
