Causes of Concrete Foundation Cracks

Dealing with concrete cracks

Sooner or later, concrete cracks.  Sadly, there is not a lot of ways around it. There is technology to control where concrete cracks and fix them when they happen but there is not a lot of tactics for preventing cracks.

However, when it comes to your foundation it is important to understand what causes foundation cracks. That way you may be able to control some of the elements to prevent cracks before they happen.

Here are some of the common causes of foundation cracks:

Tree roots

Trees and bushes that are planted too close to the foundation wall can cause foundation cracks.  Basically, the roots keep growing naturally and when they hit the concrete wall they keep pushing against the foundation causing it to crack.  To prevent this scenario, avoid planting trees and deep root bushes too close to the foundation wall.  It is easier to remove the tree than it is to move your house.

Hydrostatic pressure

Hydrostatic pressure happens when water builds up in the soil. As water saturates the ground, the soil expands and increases the pressure that is pushing up against the foundation wall.  This pressure can crack the foundation wall which typically manifests itself in horizontal cracks.   To prevent this, don’t let excess water build up along the foundation wall.  Make sure the gutters and downspouts are working together to channel the water away from the house.  The soil grade should angle away from the house to let any water fall away from the foundation not toward it. French drains can also help relieve hydrostatic pressure by channeling water away from the house.

Freeze/Thaw cycle

Concrete naturally expands and contracts with the elements.  As the ground around the foundation freezes and thaws the concrete expands and contracts often causing small vertical hairline cracks.  Most of the time, these cracks are not serious but should be fixed before they let in water, soil gases, or insects and pests.  Sometimes when a contractor pours a concrete foundation they include expansion joints to allow for the natural movement of the concrete to happen without causing the concrete to crack.  If your foundation cracks due to the freeze and thaw cycles, just get the fixed as soon as possible so they don’t get worse or cause other problems.

Settlement

Soil settlement can also cause foundation cracks.  This usually happens if the footing was not properly supported, backfilled, or if the soil under the foundation was not properly compacted.  Settlement cracks can also happen if there is excavation work going on in the area.   This sometimes will change the soil environment and cause the ground to shift under the footing.  You can know if the crack is from a settlement issue if the crack is actively moving.  It is hard to prevent this from happening but if it does foundation repair contractors have systems to stabilize the foundation and prevent the crack from moving anymore.

If you have a foundation crack, it is important to call a professional to repair the crack and assess the situation. If it is a structural crack that is affecting the integrity of the building or house, you may have to consider shoring up the foundation with anchors, underpinning, or carbon fiber systems.  A professional foundation repair contractor can help diagnose the problem and recommend the best systems for your situation.