Best Ways To Fill A Void Under A Concrete Slab

October 11, 2022 Baird Foundation Repair

Whenever your kids are playing outside, it can already be stressful enough to try 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, even 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, can make your floors uneven, and even cause total foundation destruction.

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

What Causes Concrete Voids?

Concrete voids occur when changes in the soil around and underneath the concrete cause structural problems within a much larger area. The most notable structural problems can be found in the home’s foundation or the sidewalk surrounding it. Looking into different variables, such as plumbing leaks and water damage, can provide a good explanation for the soil changes. 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 consider concrete leveling. This process does the simple work of filling the gaps under these slabs, which will stop any of the symptoms from showing or persisting.

Filling the Concrete Voids

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


Mudjacking is a traditional and common form of slab jacking. 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 when 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 about the size of a pea and pretty undetectable. (Normal mudjacking leaves a 1” hole, which is strikingly 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!