Basement Floor Cracks

Why Do Basement Floors Crack?

Like foundation walls, basement floors are prone to cracking. Most floors are poured at a thickness of 4″ or less, which makes them more susceptible to cracks. Some builders will cut “control joints” into the floor to help “control” where the cracking takes place, knowing that in most cases some cracks will develop.

Is it necessary to repair floor cracks?

Repairing floor cracks is certainly beneficial for several reasons:

  • First, floor cracks should be repaired if a basement is going to be finished and floored, especially if carpet is going to be placed over the floor.
  • Floor cracks are a source of moisture that will penetrate into the flooring and can cause a musty odor. The only exception to this is when ceramic tile is put down. Carpet companies will tell you that there is a moisture resistant pad that can be put down first, which is true, but excessive moisture can go through the pad into the fibers of the carpet, causing an unpleasant odor.
  • Repairing floor cracks is also beneficial to stop radon gas, the second leading cause of lung cancer, from penetrating through the cracks into your home. Homeowners don't always realize that up to 50% of the air we breathe comes from the basement.
  • Another reason to repair floor cracks is to help prevent insect intrusion, especially if the plan is to finish the basement.

How to fix Basement Floor Cracks

There are two ways Crack-X repairs floor cracks:

  • The first is a gravity-fed injection process of a two-part epoxy resin, coupled with coarse sand. This repair actually "welds”, or glues the concrete back together and penetrates through the thickness of the pour. The "weld" that's created is a permanent repair and will not allow radon gas, moisture, or insects to penetrate through
  • Epoxy is like a super glue, so once it cures, it makes the floor monolithic again, like it was originally purposed.
  • Repairing floor cracks does not come with a warranty against water intrusion due to the hydrostatic pressure created under a floor, which can be too great to prevent further cracking in some cases. Basically, if the water table is too high and it's pushing against the floor,it can cause additional cracking.
  • For those looking to clean up the basement and paint the floor after repairing the cracks, an epoxy repair works best. It hardens and can be ground to create a smooth surface in order to apply paint.
  • The second process used to repair floor cracks is a self-leveling urethane polymer which adheres to the concrete. This prevents intrusion of radon gas, moisture, and insects, but it does not penetrate through the entire floor. For homeowners that do not plan to finish the basement, a urethane polymer is an inexpensive alternative to an epoxy.
  • Over time, urethane polymer can open up due to the movement in a floor ,because it does not have the structural properties of an epoxy.

Fixing Uneven Basement Floor Cracks

In some cases, cracks form in floors and become displaced, with one side being higher than the other, resulting in a tripping hazard. In these instances, the cracks can be ground down to “take the curse” out of the displacement, then filled with an epoxy resin or paste of the proper width.

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