Perhaps you are looking to raise the garage floor. Or maybe you just suspect that there is trouble around the corner with your concrete driveway. Regardless what type of concrete raising or concrete service you are looking to perform, it is important to know how to recognize when you have a potential void in your concrete that would require filling.
What is a Concrete Void?
The first thing to understand is that voids in concrete are not visible. Unlike traditional crack repair (which is very visible), a void in the concrete can build up over time, eventually causing massive damage to the surface of the concrete, requiring large repairs. One of the reasons voids are not detectable by surface damage at first is that concrete is very strong. Average concrete can withstand about 3000 psi (pounds per square inch), and some concrete has a strength of over 20,000 psi. Because of this, the concrete will withstand enormous amounts of pressure and stress, until eventually the entire slab just cracks. When it does crack, the crack is usually massive.
The most high-tech solution is to use a GPR, or ground penetrating radar. GPRs are used by contractors to detect voids or holes under a concrete slab. If you are looking to raise the garage floor, it could be because you have a void in your concrete. Garage floor voids are difficult to detect without a GPR. Without a GPR, you might be able to detect a void by driving into your garage and listening to see if you can hear a shallow or hollow sound as you drive over the concrete. Sometimes there will also be tiny cracks throughout the concrete, or sometimes you will be able to detect a shift or tremor in the concrete. All of these are signs that you should look to raise the garage floor and fill the void.
How to Fill Concrete Voids
Filling concrete voids can be tricky. Because the void typically isn’t accessible through a visible crack (yet), there are only a couple of options. For small slabs, such as a sidewalk, it is possible to pack under the slab with gravel or some other material to keep the void from damaging the concrete. For larger slabs, such as a patio or garage, this isn’t usually an option.
One of the best methods for large slabs is to use some sort of expanding polymer substance, such as Polyurethane. Polyurethane can travel several feet through openings on the side of your slab to find and fill the voids underneath. This can sometimes be enough to prevent any further damage to the slab, even if you are looking to raise the garage floor.
When to Hire a Professional
Concrete can be expensive, and so is fixing it. Sometimes, because of the nature of a slab (especially in a garage), it can be difficult to access places where you can easily fill a void using Polyurethane or another expanding substance. Even if you want to raise the garage floor, you will need to fill the voids underneath in order to ensure good concrete strength and durability. There are plenty of options for slab jacking and soil cement stabilization that can be done professionally to ensure that your concrete is secure and solid for years to come.