Concrete Sidewalk Raised with PolyLEVEL in St. Louis, MO

Challenge

The concrete porch and sidewalk slab at this St. Louis, Missouri home had developed a significant void underneathe, causing the sidewalk slab to settle and sink beside the porch slab.  The sunken sidewalk could be easily spotted from the front of the home, making it an eyesore to the neighborhood and a trip hazard to the homeowners.  The unsightly settlement would also pose a threat to their property value in the event these St. Louis residents ever decided to sell their home.

The sidewalk had settled more than 4 inches on one side, exposing a void under the porch.  The cause of the slab settlement was likely the downspout beside the porch that had not yet been buried or extended away from the home.  Though it has since been repaired, this downspout did not always have an extension attached.  On rainy days, the downspout most likely dumped rainwater from the gutter beside the porch and sidewalk.  Over time, pooling water beside the porch could have eroded the soil beneath the porch and sidewalk, and dry seasons would have caused the soil underneathe to shrink—creating the void.  A void beneath a slab is no match for the weight of the heavy concrete.

Solution

Woods Basement Systems' David Fantini inspected the slab settlement and recommended PolyLEVEL over traditional mudjacking or concrete replacement.  Replacing the concrete would have been expensive, disruptive, and would not have addressed the soil—which likely caused the problem in the first place.  Mudjacking the slab would have made the problem worse; several large 1-1/2 inch holes would have been drilled to pump grout into the void, which would have also spewed out of the other holes.  Mudjacking also adds weight to the underlying soil—making a settlement problem even worse—and the material can erode or wash out.

PolyLEVEL is a proven, engineered solution specifically for concrete leveling.  Project Foreman David Gass and Co-Foreman Jeff Bosick began the installation by drilling only a few, small 5/8-inch holes in strategic locations in the slab and installed injection ports.  This allowed them to use specialized equipment to inject the structural-grade, highly-expansive polyurethane into the void.  Once the void was filled, the expanding properties of the polymer allowed for accurate lift to level the slab.  The few small holes were grouted, and the joint at the porch and joints in the sidewalk were sealed.

The lightweight PolyLEVEL only adds 2 pounds per cubic foot where it is installed, unlike the 140 pounds of pressure exerted by concrete or mud.  And these homeowners never have to worry about waterproof PolyLEVEL eroding or washing out.  As a bonus, their sidewalk was cleared and instantly available following the installation.

Project Summary

System Design Specialist: David Fantini

Project Foreman: David Gass

Co-Foreman: Jeff Bosick