To effectively raise and stabilize a sunken slab, concrete lifting contractors address the cause of the problem – voids or empty pockets of air in the soil underneath.
In and around Salt Lake City, voids often arise as a result of concrete heaving, or the upward movement of a slab. This often occurs with our clay-heavy soil, as it swells and shrinks when moisture levels fluctuate. The repeated freeze-and-thaw cycles we see in northern Utah is a contributing factor, too, and for many property owners, issues like tree root growth, improper land grading and poor water drainage lead to the develop of soil voids.
Other outside influences, such as insufficient soil compaction or another mistake during the installation of a concrete slab, can also set the stage for voids to form. Whatever the cause, filling these air pockets under a slab is the key to restoring it to a level position – but first, the gaps need to be found. Here, we explain how professional concrete lifting contractors accomplish that task.
Soil Void Detection with Ground Penetrating Radar
When you see that a slab is sinking, you know there’s a gap in the soil underneath. But, the precise location and size of the void can’t be determined with a quick glance – and guessing isn’t going to raise a sunken slab back to an even and stable position.
To figure out exactly where the soil voids are located and how far they extend, concrete lifting contractors rely on ground penetrating radar. GPR technology involves the use of high-frequency radio waves, which are sent down into the ground. When the equipment detects an anomaly in the soil, a signal goes to the receiver. The process is fast, and scanning for soil voids doesn’t do any damage to the concrete.
Interpreting GPR Data for the Purpose of Concrete Lifting
Every anomaly detected by ground penetrating radar isn’t necessarily a soil void. The GPR transmitter also reflects a signal toward the surface when it encounters an underground pipe, large boulder, tension cables or any other subsurface object.
So, how do concrete lifting contractors know if a signal indicates a pocket of air in the soil or something else? The answer has to do with the way GPR technology works. When radio waves travel through different types of matter, the amount of time it takes for the signal to reach the receiver is different. Soil voids can be distinguished from rock and from objects made of PVC, metal and other materials through their unique GPR signature.
That said, GPR data isn’t all that straightforward – the information is presented in the form of a wavy line map, not images of what’s actually underneath the sunken slab. However, concrete lifting professionals are highly trained in the art of ground penetrating radar and can easily make sense of the results.
Concrete Lifting is a Long-Term Solution for a Sunken Slab
As we mentioned, filling voids in the soil is of the utmost importance when it comes to raising and stabilizing a sunken slab. But what about simply replacing the concrete? Isn’t that an alternative for Salt Lake City property owners to consider?
While a slab that’s sinking could be removed and replaced, going that route means leaving the gaps in place – and that means the newly poured concrete is almost certainly going sink at some point. With the high cost of tearing out and replacing a slab, you’d hope that wouldn’t happen, but since the concrete tear-out and replacement process doesn’t involve filling the soil voids, the slab sinking in the future is practically a given.
In contrast, the results of concrete lifting typically last for about a decade. And not only is concrete lifting a long-term fix for a sunken slab, it’s also the cheapest repair option. However, when air pockets in the soil are the result of burrowing animals, drainage issues or tree root growth, these problems must also be resolved to make the development of additional voids and further sinking unlikely.
Schedule a Free Concrete Lifting Consultation Today
If you have a sunken slab at your Salt Lake City home or business property, the professional team at Lift-Up Concrete can provide you with a fast, expert fix for an affordable price.
We offer complimentary, no-obligation consultations and transparent estimates for concrete lifting. We always level with our customers, and we’re happy to answer questions about the work we do. With Lift-Up Concrete, you can expect exceptional service, no matter the size or scope of your repair project.