If you have a crack in your basement walls and do not treat it, it’s possible that the crack is going to get worse. Cinder block wall foundations are especially problematic. If you have a crack in your wall, water is going to use that as a way in. Additionally, because the wall is literally cracked in two pieces, the movement of the walls due to pressure from the outside will work the cracks open even more, causing attempts to patch the crack to fail and increasing the size of the crack.

One crack leads to another, and no crack is ever going to improve on its own. Repair all cracks that are letting water in or are exposed to moisture to avoid further damage. If you find foundation cracking that suddenly forms and is more than 1/16” (0.16cm) in width, it needs immediate professional attention.

Horizontal Cracks

These cracks weaken your walls much more than vertical ones and can lead to complete failure of the walls. These cracks are caused by pressure against the side wall that can snap the walls. If you can fit a dime into the crack in the wall, get a professional opinion from a foundation contractor. There are many options available for fixing bowed walls, such as braces, helical piering and reinforcement that can repair your wall, add strength, stop the inward movement of your walls, and redistribute the weight on your basement walls.

Vertical Cracks

Most vertical cracks in a foundation wall do not seriously damage the structure of your home. Vertical cracks are most often caused by the shrinkage of the concrete as it cures, but they also tend to occur from damage as the foundation settles. When looking at a vertical crack, run your fingers across it- if the sides of the crack are even, then that’s a sign that the crack formed as the concrete cured.
The more significant problem in this case is that you are now vulnerable to water from the earth seeping into your basement. If the cracks are uneven to the touch, then external pressures could be the cause.

Finding and Monitoring Cracks

Many homeowners find cracks in their foundation walls long after they’ve formed. These homeowners can become very distressed, thinking that the crack has suddenly appeared. While that may not be the case, it is important to treat all wall cracks as potentially serious problems until they’ve been assessed by a professional.

Cracks tend to form most often at weak points and openings in your foundations walls. These include corners, edges of basement window frames, pour lines, holes for service, pipe penetrations, long spans of wall, and tie rods in your foundation. If you find a crack, check on it regularly. If you suspect that the crack is moving, spreading or widening, the fatigue on your basement walls is increasing, which will lead to further damage and eventual foundation failure. Monitor the crack’s length by marking off the ends of the crack on the plaster, tile or brick with a pencil. Be sure to also draw several “alignment” marks across the crack at various points to ensure that the crack is not shifting unevenly. Add the date on the side of the marks to monitor how quickly the wall is deteriorating.