Concrete floor cracks:

There are many issues that can lead to cracks in concrete floors. While poured concrete is generally considered the best, it is still prone to cracking due to the curing process and settling. During the curing process concrete generates a lot of heat which creates small cracks called shrinkage cracks. These cracks exist because concrete is “thirsty” during the curing process and requires constant water to prevent it from shrinking. Most concrete floors do not get the needed water thus they tend to crack. Over time shrinkage cracks getting larger due to normal settling and movement in the floor. As a general rule any concrete pour larger than a 12’x12’ area usually cracks. Most basement floors are 4” thick so it doesn’t take much for them to crack.


Basement floor cracks are almost never structural issues which require immediate repairs. Basement floor cracks are a huge source of excessive moisture and humidity. Excessive moisture can ruin belongings being stored in the basement, not to mention the potential for mold growth. Basement floor cracks are usually repaired prior to a basement being finished for living space. Floor cracks are a source of excessive moisture in a basement, an enemy of a finished area. Moisture wicking up through the cracks increases the humidity and can create a moist musty environment. Over time that moisture can create issues with mildew and mold and increasing musty smells that are often associated with finished basements. Many homeowners choose to put carpet down on the concrete for flooring. Carpet that gets moist from non repaired floor cracks will feel wet and can create a musty odor.

Another reason to repair floor cracks is to stop the infiltration of radon gas, the second leading cause of lung cancer in the USA. Radon gas is a silent odorless gas that creeps in directly through basement floor cracks. Under extreme conditions a radon mitigation system may even be required. Sealing floor cracks with the Crack-X method fills the entire 4” of the floor crack, bonding or welding the floor back together.

Some cracks are large enough to allow insects into the home potentially creating a future nightmare. Carpenter ants and termites like wet dark conditions, like basements. Again prior to finishing a basement all floor cracks should be sealed to prevent insect intrusion or even rodent intrusion, like snakes or mice.

Under some circumstances it is recommended to repair floor cracks that are allowing water to seep through. If there is minimal water gathering on the floor coming in through floor cracks then a gravity fed injection process can fill the 4” floor and stop the water. Typically this can be done to newer homes that have drainage and or stone under the floor. By stopping the water coming through the floor cracks it pushes it to the drainage. In some cases it is best to install a sump pump in the basement to allow for a controlled water table. Most homes built within the last 20 years have some stone under the floor and would be a good candidate for floor crack repair coupled with a sump pump to control the water.


The most economical way to repair floor cracks is with the gravity fed system. A polymer is used to create a bond between the concrete crack and fills the entire void through to the bottom. Larger cracks are injected using the gravity fed system but also are mixed with a course sand to create an aggregate, thus strengthening the bond. Some choose to just seal the surface of the crack with a simple urethane product. Epoxy can also be used to fill basement floor cracks and will weld the concrete back together creating a monolithic pour as originally intended.