What Causes Basement Foundation Walls Cracks and Failures
It is an unfortunate and little known fact that almost all residential foundations have some basement foundation cracks in their concrete walls. These cracks typically occur in wall or window corners, around holes for service lines or rod ties, and in pour lines. There are a number of causes to for these cracks and the rest of this article will discuss a few of those causes in more detail.
Improper Concrete Mix
Concrete is the most commonly used material in residential home foundations and is made by mixing mortar, plaster, water, and various types of aggregates like gravel, crushed stone, and gravel. The amount of water used is critical to the strength of the cement. The less water in the mixture, the stronger the cement will be. But by adding more water the concrete is easier to maneuver but less durable. Impure water can also be a problem and can cause settling or premature failure.
Rapid Concrete Curing
After concrete has been placed it needs to be properly cured in order to ensure maximum strength an increased resistance to cracks. Concrete takes a large amount of time to cure and requires a moist, controlled environment to achieve full potential. If the concrete drys too fast shrinkage will occur and the concrete will not gain full strength and cracking can occur. Crack's in your home's foundation could be the cause of concrete that was improperly cured.
If the area around your foundation drains poorly then it will take longer for water to be removed from the area. Increased water in the area can mean more water pressure on the foundation wall. Add to that the pressure of the surrounding soil and sometimes there is more pressure than the wall is designed to withstand, which can leads to bowed, cracked, or leaning walls.
Soil is considering expansive clay when it dramatically expands or contracts with variations in water levels. If you home was built on expansive clay then the soil around your home will swell when it is wet. This may not seem like important, but some clays can expand very substantially and increase pressure on your home's basement foundation wall by over several tons per square foot. With that much increased pressure on the wall, it wouldn't a be a surprise if the walls started to crack.
These are just a few of the different causes of foundation wall failure and cracks. It is important to note that this is a very small part of a much larger list of issues that can effect the structural integrity of your foundation wall.
We'll talk a little bit more in our next article about the differences between vertical and horizontal foundation wall cracks and what they mean for your repair efforts.