Best Ways To Fill A Void Under A Concrete Slab

October 11, 2022 Baird Foundation Repair

Whenever your kids are playing outside, it can be easy to protect them from structural dangers, such as the road or trees. But whenever voids start to form around the concrete outside of the house, sidewalk chalk can become a disaster. Concrete damage can happen around, in and under your house. These crevices have huge impacts on the leveling of your walls, an uneven floor and even total foundation destruction.

Whether you’re looking for sidewalk repair for roller skating or looking to prevent long-term damage to your foundation, filling voids early, with Baird Foundation Repair, can increase the integrity of your home as well as maintain its value.

What Causes Concrete Voids?

Voids occur when changes in soil around the concrete cause structural problems within a larger area. The most notable changes are in a home’s foundation or the sidewalk surrounding it. Looking into different variables, such as plumbing leaks and water damage, can provide a good explanation, but there are many other factors to consider, such as extreme weather and soil consolidation.

When you’re looking to heal voids within your concrete, you should look into concrete leveling. This process does the simple work of filling the gaps under these slabs, which will stop any of the symptoms, such as cracking, from showing.

Filling the Voids

A majority of the time, professionals fix sagging concrete by using slab jacking. This is especially prevalent if you managed to catch the void before there were significant symptoms, such as cracking or unevenness.


A type of sand-cement slurry (called “mud” in the industry) can be used to fill voids under concrete slabs. This mixture of sand, cement, and water is pumped through holes drilled in a slab foundation to fill voids underneath. While this type of slab jacking can be cost-effective, there are some potential drawbacks to going for this type of repair.

  • Void penetration is not always exhaustive, and this can result in future damage.
  • The curing time for the filled concrete is extensive (approximately two to three weeks depending on airflow).
  • Cementitious slurry is heavy and can be time-consuming to dig through should under slab plumbing repairs on plumbing be needed in the future.

Check out our blog post to learn more about mudjacking vs. polyurethane foam.

Foam Injection with PolyLevel®

PolyLevel® is a state-of-the-art concrete leveling method that uses high-density polymer expanding foam to achieve slab stability. This high-density foam is injected into small holes drilled into your concrete slab. Upon injection, the polyurethane foam chemical reacts causing an expansion to fill and seal void defects. PolyLevel has a very short drying period and is non-erosive to the material around it.

Baird Foundation Repair’s PolyLevel® is a cost-effective way to level your concrete and has more advantages than traditional mudjacking:

  • The cure time is only 15 minutes as compared to 24+ hours.
  • The hole size needed for the repair is ⅜”, which is the size of a pea and makes it borderline undetectable. Normal mudjacking leaves a 1” hole, which is heavily noticeable at the size of a quarter.
  • PolyLevel® is 50 times lighter than normal mudjacking. It only weighs 2 pounds per cubic foot! This results in a lighter load being put on the soil underneath the concrete slab, allowing you to rest easy about your concrete repair for years to come.
  • The fully sealed PolyLevel® injection is waterproof, meaning that any moisture that seeps in from the soil underneath the slab won’t cause future cracks or sinking.

Contact Us!

Baird Foundation Repair is the perfect provider for concrete leveling! With our industry-leading approach and lifetime warranties, we are here to provide the best foundation services in Texas. We have plenty of financing options available and permanent solutions to your home issues, so you can restore your peace of mind without sacrificing your wallet. Call us today!