Void Filling Under Concrete Slabs in Edmonton
Voids beneath concrete are invisible but destructive. They form when soil erodes, washes away, or compacts over time, leaving your concrete slab with nothing to support it. In Edmonton's harsh climate, where freeze-thaw cycles accelerate soil movement, void filling is often the critical first step to preventing costly concrete failure.
At Poly Lift Solutions, we use high-density polyurethane foam injection to fill voids and stabilize the soil beneath your concrete slabs. This proactive approach can prevent sinking before it happens - or stabilize existing settlement to prevent further damage.
Real Edmonton Results: Before & After
Warning Signs of Voids Under Your Concrete
Voids don't announce themselves with obvious damage right away. Here are the early warning signs that indicate voids may be forming beneath your slabs:
What Causes Voids to Form Under Concrete?
Understanding what creates voids helps you prevent future problems. In Edmonton, several factors commonly contribute to void formation:
Water Erosion
Poor drainage, downspout runoff, and spring snowmelt wash away soil beneath your concrete. Over years, this creates significant voids that undermine slab support.
Freeze-Thaw Cycles
Edmonton's 50+ annual freeze-thaw cycles cause soil to expand and contract repeatedly, creating gaps and air pockets beneath concrete slabs.
Soil Settlement
Fill dirt used during construction compacts over time. If initial compaction was inadequate, the soil gradually settles, pulling away from the concrete above.
Organic Decomposition
Tree roots, buried organic matter, and vegetation beneath concrete decompose over time, leaving voids where solid material once existed.
Our Void Filling Process
We use high-density polyurethane foam to fill voids and stabilize soil beneath your concrete. Here's how the process works:
Assessment & Detection
We thoroughly inspect your concrete, identifying void locations through visual inspection, sound testing, and probing. We'll explain exactly what we find and recommend the best solution.
Strategic Drilling
Small 5/8" diameter holes are drilled at calculated points to access the voids beneath. These holes are much smaller than traditional methods require.
Foam Injection
High-density polyurethane foam is injected into the void spaces. The foam expands to fill cavities, penetrating loose soil and compacting it as it cures.
Soil Stabilization
As the foam expands, it bonds with surrounding soil particles, creating a stable, water-resistant base that prevents future erosion and settlement.
Hole Patching & Cleanup
Injection holes are patched to blend with existing concrete. The foam cures in minutes, and you can use your concrete immediately.
Why Polyurethane Foam for Void Filling?
Traditional void filling methods use sand, grout, or cement slurry - materials that can wash away again. Our polyurethane foam offers significant advantages:
Waterproof
Won't wash away or erode like sand or grout
Lightweight
Doesn't add stress to underlying soil
Expanding
Reaches every cavity and fills completely
Bonds to Soil
Creates unified, stable support base
Fast Cure
Hardens in minutes, not days
Permanent
Won't break down, shrink, or degrade
Common Void Filling Applications
Void filling is used both as a preventive measure and a repair solution across many applications:
Frequently Asked Questions
The most common sign is a hollow sound when you walk on or tap the concrete. Other indicators include visible settling, new cracks, water pooling in unusual spots, and gaps appearing between the slab and adjacent surfaces. If you suspect voids, we offer free assessments to confirm and locate them.
Void filling costs depend on the size and depth of voids, accessibility, and total area affected. Most residential projects range from $500-$3,000. We provide detailed, transparent quotes after our free assessment - no surprises or hidden fees.
They're related but different. Void filling focuses on filling empty spaces beneath concrete to prevent future sinking. Concrete leveling (polyjacking) actually lifts sunken slabs back to their original position. Often, we do both - filling voids first to stabilize the area, then lifting the concrete if needed.
Yes - that's often the primary goal. By filling voids before significant settling occurs, you prevent the concrete from dropping and cracking. Proactive void filling is much less expensive than waiting until you need full concrete leveling or replacement.
Most residential void filling projects are completed in 1-3 hours. The foam cures within minutes of injection, so your concrete is ready for normal use immediately after we finish.
When performing void filling only (not leveling), we carefully control the foam injection to fill voids without lifting the slab. Our experienced technicians monitor the process to ensure we achieve stabilization without unwanted movement.
Yes. Void filling is used across both sectors, though the scale and approach differ. Residential projects typically involve driveways, garage floors, sidewalks, and patios. Commercial projects often cover larger areas: warehouse floors, loading dock approaches, parking lots, and industrial slabs. We have the equipment and experience for both, and we’ve been serving Edmonton residential and commercial clients for over 11 years.
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