Causes & Fixes for Basement Floor Cracks

If there is one sure thing in life, it is that concrete will crack. Contractors try to plan for the cracks with control joints and expansion joints but sometimes the concrete cracks where they don’t want it to.

When a basement floor cracks in Waukesha it becomes a gateway for water, radon (and other soil gases), odors, and pests and insects to enter your house.

Why Does Concrete Crack?

Shrinkage

By nature concrete will shrink as it cures and again during the freeze and thaw cycle as concrete naturally expands and contracts. Sometimes during this process, either during the first stages of curing or during the first freeze-thaw cycle, a concrete slab will crack. Control joints are set into the concrete to allow for the concrete to crack in the line. Expansion joints are lines in the concrete that allow for the concrete to expand and contract to limit the shrinkage cracking. The reason it cracks is that as it shrinks and expands there is no room for the concrete to move so it buckles under the pressure of itself locked into a form such as a basement foundation. Most of the shrinkage cracks can be controlled with expansion or control joints set during the pour but if by chance you get a shrinkage crack remember they are nonstructural and can be easily fixed with a concrete crack injection material. Caulking will not work on concrete cracks. They need pressurized epoxy or polyurethane to completely fix the crack.

Settlement

Settlement cracks happen when the ground below the concrete moves and settles after the concrete is poured. Sometimes settlement happens because the soil wasn’t compacted correctly or the soil could be naturally unstable. Expansive soil contracts and expands with the change of seasons. If the foundation is built on expansive soil it will be more prone to settlement cracks. Sometimes outside sources impact settlement issues and cause the concrete floor to crack. For example, vibrations from construction close by or earthquakes can move the soil and cause settlement.

Water

Water is a powerful source that can cause foundation and basement floor cracks. If there is water in the soil around and under the foundation there can be hydrostatic pressure built up around the foundation that can cause cracks. Heavy rain can cause enough hydrostatic pressure under the floor to crack the floor.

Tree Roots

Trees are another one of nature’s powerful elements. If a tree is planted too close to a foundation the tree roots can actually push against the foundation cracking the walls and floor.

Most basement floor cracks are nonstructural. However, concrete cracks left alone will make the issue worse and could be a sign of a more serious structural issue. Get your basement cracks inspected by a professional structural repair contractor.