Slab-raising techniques have changed dramatically over the years. Slab-raising is often referred to by other names, such as slab-jacking, mud-jacking and concrete leveling. The names are often mistakenly used to mean the same thing; however, there are important differences. Mud Jacking, for example, uses grout or liquid asphalt which is pumped through drilled holes in the concrete. The different names usually refer to the different materials used to level the concrete. The most effective slab-raising technique used today is injecting polyurethane foam beneath the uneven or cracked concrete. Uneven concrete is a safety hazard. In many cities throughout the country, homeowners are considered responsible for their own sidewalk repair. Some cities offer a cost-sharing program.
The Problem with Older Concrete Leveling Methods:
Old school techniques entailed demolishing uneven, cracked or sinking concrete and replacing it with more concrete. The problems with this method are: 1.) It’s expensive. 2.) Fresh concrete can take days to cure before it can be used again. 3.) If soil conditions, such as soil compression or unstable soil, caused the initial problem, concrete damage can occur again. 4.) If erosion is the culprit, soil stabilization must be implemented before any solution will work effectively. Meanwhile, the property owner is liable for safety issues--anyone who trips or falls over the uneven concrete. Over the years, other methods have been tried, such as grout pumping. The grout is in the form of a slurry, which can be some combination of dirt, stone, sand, Portland cement and water. This mixture is pumped under the concrete slab to raise it to its proper level; however, large holes are drilled into the existing concrete to provide access for the spray nosel. The down side is the risk of messy spills occurring through the cracks and crevices, and it takes time for the grout to harden. Again, if soil stabilization has not been addressed, the problem is likely to re-occur. Problems have occurred, such as poor adhesion to the old concrete. Poor adhesion can result in the detachment of the concrete or cracking, and the added weight can cause more sinking and cracking.
Another technique is called “Concrete Grinding”. Essentially, the higher concrete areas are ground down until the surface is even with the sunken surfaces. This type of repair must often be repeated as the soil beneath continues to move up and down. The process is not conducive to a achieving clean, smooth appearance Again, unless soil stabilization is done, the problems will continue.
Polyurethane Foam Jacking Is the Most Effective Solution:
The cost-effective, lasting solution is to inject spray foam. This process entails drill one or more small holes in the affected concrete and injecting foam under the slab. The foam expands quickly and raises the concrete slab to its proper position. The foam expands within minutes, restoring the concrete’s functionality quickly. The small holes are simple to repair which allows for a more esthetically pleasing appearance. Polyurethane foam is widely used by applicators as a preferred method to achieve affordable, effective, fast, permanent results.
How Does Polyurethane Foam Raise Concrete?
Polyurethane foam jacking is comprised of two components that, when mixed together, cause the material to expand. This reaction causes gas bubbles to form that have the amazing power to lift heavy concrete slabs. As the foam expands, it fills voids, cracks and crevices beneath the slab creating a stable substructure. Once the ground is stable, the foam continues to expand gently “floating” the concrete slab back into place.
What are the Benefits of Using Polyurethane Foam?
Polyurethane foam has tremendous compressive strength for lifting and weight bearing. It has a high tensile strength, is pliable and does not lose its density. Yet, it can stand up to traffic, vibration and ground movement. It is light weight, water resistant and can cure in as little as 15 minutes.
Slab-raising, with polyurethane foam, is a viable solution for concrete settlement cracks and uneven surfaces for foundations, driveways, sidewalks, steps, garages, basements, porches, patios, pool decks, interior slab floors, roadways, soil stabilization and just about anywhere else concrete has been installed. It can also be used for commercial and industrial structures, including railroad subgrades.
Consult a Professional:
It takes an experienced professional with the right equipment and material to raise and repair concrete effectively for long-lasting results. Professional concrete raisers understand the how soil types, weather conditions, freezing and thawing, hydrostatic pressure and erosion affect the ground and concrete structures over time.