Could There Be a Void Under Your Garage?

There could be a void under your garage, and it’s more common than many Atlanta and Alpharetta homeowners realize. Hidden gaps beneath concrete garage floors can develop over time, leading to uneven surfaces, cracks and even structural instability if left unaddressed.

How Do Voids Form Beneath Garage Floors?

A void under your garage is simply an empty space between the concrete slab and the supporting soil. These gaps often result from soil settlement, water-related erosion, poor backfill during construction or even animal activity. As the supporting soil shifts or washes away, the concrete above loses support. Signs of a void may include a garage floor that sounds hollow when tapped, visible sinking or sloping, new or expanding cracks or vibration when you drive over certain spots.

What Problems Can a Void Under Your Garage Cause?

A void isn’t just an empty space—it’s a risk to your property. Even a small gap can cause a concrete slab to flex, leading to cracks that worsen over time. These cracks let water seep in, accelerating erosion and worsening the problem. If left untreated, a void under your garage can result in:

• Uneven or sunken concrete slabs
• Widening cracks
• Doors that won’t close properly
• Difficulty parking vehicles
• Potential safety hazards for your family

Over time, ignoring a void can cost far more than early intervention, especially if the slab needs to be replaced entirely.

How Is a Void Under Your Garage Repaired?

Advance Concrete Lifting and Leveling specializes in filling voids and restoring concrete garage floors to their original level. One of the most effective solutions is polyurethane foam injection with FILLFOAM™. This process involves drilling small holes in the affected slab and injecting a high-density expanding foam beneath it. The foam fills the void, lifts the concrete back to level and hardens to create strong, lasting support. Compared to traditional mudjacking, polyurethane foam is lighter, more water-resistant and cures much faster—meaning you can return to using your garage the same day in most cases.

Our team also inspects for signs of ongoing water intrusion and provides recommendations to prevent future erosion, helping ensure your repair stands the test of time.

What Sets Advance Concrete Lifting and Leveling Apart?

With years of experience serving Atlanta, Alpharetta and surrounding communities, Advance Concrete Lifting and Leveling has built a reputation for honest assessments, cutting-edge technology and quality workmanship. Our technicians are highly trained to diagnose voids under garage floors and recommend the right repair solution for each unique situation. We use only the latest polyurethane materials and state-of-the-art equipment, ensuring lasting results with minimal disruption to your home and schedule.

Frequently Asked Questions

How do I know if there’s a void under my garage?

Look for uneven or sloping floors, new cracks hollow sounds when tapping the slab, or a garage door that doesn’t close smoothly.

Is polyurethane foam safe for my garage?

Yes. Polyurethane foam is environmentally friendly, durable and won’t wash away like traditional mudjacking materials.

How long does the repair take?

Most void repairs using polyurethane foam can be completed in a few hours, and your garage is usually ready for use the same day.

Will filling the void prevent future issues?

Filling the current void stabilizes the slab, but you should also address any drainage or water problems to prevent new voids from forming.

Can you repair cracks as well?

Absolutely. We offer crack repair services alongside void filling to restore both the appearance and structural integrity of your garage floor.

If your garage floor seems uneven, feels hollow or shows new cracks, don’t wait. Contact Advance Concrete Lifting and Leveling today for an expert assessment and effective, long-lasting repair.