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Why do Concrete Foundation Walls Crack?

13 years ago
Your foundation is made of concrete. When concrete is made you can be assured of two things; the concrete will get hard and the concrete will crack. Concrete foundation walls crack for numerous reasons.

Concrete is one of the best building materials ever devised by man. Concrete is a building material made from mixing Portland cement, sand and water. After you mix the concrete two things will happen. It will get hard and it will crack. When it’s done right concrete will last a long time. But it will crack; it is just a matter of when.

Look at the concrete next time you go to the store. There are cracks in concrete everywhere. If the walls, floors and sidewalks are made of concrete, they probably have cracks in them.

Concrete foundation walls crack because:Shrinkage. As the concrete cures the moistures evaporates out. This evaporation can cause the concrete to shrink. Shrinkage is a common factor in all concrete and oftentimes causes cracking.

Settlement. The soil that is placed around the foundation after construction is called backfill. This soil is filled back into the hole after the foundation is built. As time passes the backfill compacts and settles and this settlement can affect the foundation as well as the earth under the house settling from the weight of the house.
Stress. Foundations are stressed when pressure is applied. This pressure is either in the form of water pressure or soil pressure. The pressure is unbalanced because it is from one side of the foundation only.

Horizontal Foundation Wall Cracks and Soil Pressure

Horizontal cracks in a foundation are usually caused by unbalanced soil pressure. Most soil movement is due to what is called expansive soil which is also called clayey soil. As the clayey soil absorbs the ground water it expands. Think of rice. When you cook rice you start out with 2 cups of rice and 1 cup of water. 20 minutes later you have expanded rice and no water because the rice has absorbed the water and increased in size as a result. As the soil expands it is moving. Expansion is movement. This is known as soil swell.

A horizontal crack in a foundation wall is likely a sign that the foundation is failing under the stress of the surrounding soil swell. Your foundation wall should be acting as a retaining wall against the soil swell. The soil outside the foundation wall exerts an enormous pressure on the foundation wall. Foundation walls are designed to be strong enough to resist this load.

All concrete foundations will crack at some point. It is a fact. The severity of the cracking and it effects the structure’s integrity are varied. No crack is a good crack and all cracks should be repaired immediately.

Hassle Free Foundation Crack Repairs

Foundation crack repairs are done by A-1 Basement Solutions are:

Not Invasive
Use No Heavy Equipment
No Messy Concrete
Most Foundation Crack Repairs can be done in one day