You’ve probably stumbled across uneven concrete slabs in your neighborhood. This is a common problem, especially if the concrete slabs are placed over soft soils. Fixing this issue isn’t as complex it may seem because replacement isn’t the only option. Concrete raising is a cheaper option as opposed to replacing concrete. One of the ways concrete is raised is by using polyurethane foam, a foam that expands instantly. Read on to learn more about how foam polyurethane jacking can be used to aid in concrete raising.
How It Works
Though the administration may seem complex, it’s actually quite simple. The three basic steps of concrete raising are:

Soil Load-Bearing Capacity
Another crucial aspect of concrete raising is soil load-bearing capacity. If the soils are weak or unconsolidated, which is a frequent occurrence in the Houston area, the weight-bearing ability isn’t effectively distributed into the ground. This is due to the soil, if not densified, will inevitably slip or erode away under the weight of the concrete. This, in turn, causes the concrete to become uneven once again. If soil densification is determined to be a necessary process, it’ll look something like this:
An inspection will be done to determine where the injections will most effectively densify the soil. A typical injection pattern is at every 3-5 feet to ensure optimal spread of the polyurethane underneath the slab and in the soil.
The initial injections are completed at the top level in order to condense and strengthen the soil and use the concrete slab as a way of consolidating the top layers for the lower injections to work against.
The remaining injections are shot from the top down, with each lower layer having the capability to densify against the denser top layers. This strengthens the overall weight-bearing ability and ensures that the slab will not slip back down by consolidating the lower soils over time
For Your Understanding
In short, though concrete raising is based around the environment, there is a basic process to it. Because polyurethane can be used to lift concrete in almost any slab structure, including foundation, sidewalks, driveways, steps, garages, pool decks, etc. it’s important to gauge the environment and reasons why the concrete slabs are uneven, to begin with. This information will determine what kind of polyurethane will be used and what style of injection will be done. Polyurethane jacking is the most effective form of concrete raising and is far superior to replacing concrete altogether.
Precision Foundation Services is a Houston-based concrete lifting contractor proudly serving Eastern Texas. We provide foundation and slab repair services for residential, commercial, and industrial customers with a comprehensive suite of self-performed services. Contact us today for an estimate on your repair project.
We use NCFI Geotechnical Polyurethanes. This article was originally published on NCFIgeo.com.