Concrete raising with polyurethane foam jacking

Concrete Raising with Foam Jacking

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 ground. 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. This process is known as polyurethane foam jacking. Read on to learn more about how foam polyurethane can be used to aid in concrete raising.

Soil Load-Bearing Capacity

Another crucial aspect of concrete raising is soil load-bearing capacity. If the soils are weak or unconsolidated the weight-bearing ability of foam polyurethane isn’t effectively distributed into the ground. This is due to the fact that the soil, if not densified, will inevitably slip 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:

A lengthy inspection will be done to determine where the injections must be done in order to effectively densify the soil. A large 3-5ft square grid pattern will be laid out where the injections will be done at multiple depths.

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.

Choosing The Right Type

There are two main types of foams that are used for concrete raising. The reactivity and density of the foam need to be determined before moving on with the concrete raising process. Here’s a guide to the two factors that come into play:


A foam that reacts slowly is typically used when a large void needs to be filled. The foam will spread evenly and thicker, allowing for more coverage. A foam that reacts quickly won’t spread evenly and won’t have the same amount of spread that is offered with a slow reaction. Having control allows the workers to ensure that the slab isn’t raised too much and lines up precisely with the other slab. This ensures the success of the concrete raising process.


A foam that is much denser will be used if a larger weight needs to be born. If the slab doesn’t weigh as much and the void is large, a foam with a lower density will be used to fill in the void easier. Density is important to keep in mind as this determines the success of the operation and whether or not the polyurethane will be able to hold the weight of the concrete slab.

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 area 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. Slow reaction polyurethane is typically used for large voids to increase the spread and ensure an even rise. Density is also a factor that will be determined based on how much weight the polyurethane needs to bear. Polyurethane jacking is the most effective form of concrete raising and is far superior to replacing concrete altogether.

Concrete Stabilization Technologies sewer infrastructure repair

Polyurethane’s Role in Sewer Infrastructure Repair

Polyurethane Infrastructure RepairWhen it comes to the construction and transportation industries, polyurethane is one of the most versatile and flexible materials in the world. In its various forms, polyurethane has many applications from coatings, sealants, and adhesives to void filling, structural support, and insulation. As such, polyurethane’s use within the construction industry has steadily grown especially in sewer infrastructure repair projects.

What is Polyurethane’s Role in Sewer Infrastructure Repair?

In sewer infrastructure repair, polyurethane has several useful applications. Polyurethane foam can be used to treat inflow and infiltration issues in manholes, pipe joints, laterals, culverts, and outfalls. It can also seal off and prevent water intrusion to utility boxes, wet wells, and pump stations. Hydrophobic polyurethanes perform exceptionally well in wet conditions, making it the perfect choice for these types of repairs. Using polyurethane for infrastructure repair has many benefits. The material is lightweight, affordable, and fast curing. Despite its lightweight, this closed-cell foam has strong structural properties. It’s also minimally invasive and environmentally inert. Polyurethane repair projects require zero-excavation, which results in a small project footprint.

How Does it Work?

Polyurethane foam is created with a two-part solution. Part A is a chemical called MDI, or Methylene Diphenyl Diisocyanate (also known as ISO) while Part B is resin, a combination of polyols, catalysts, blowing agents, and other components. The two-part solution is mixed using an impingement gun and injected into voids around the affected asset. Tubes can be used to inject the polyurethane into particularly deep or large voids, or otherwise inaccessible areas. Once the polyurethane is injected, it begins to expand to fill the void and compact unconsolidated soils around the infrastructure asset. The polyurethane will follow the path of least resistance to fill and compact soils. As it does so, it will press against the asset, creating a tight seal and blocking off any cracks or other openings that could allow for water and soil to infiltrate. Due to its hydrophobic properties, the polyurethane will displace any water that surrounded the asset, ensuring a dry environment and preventing damage from moisture. Polyurethane is a fast-curing material, which means these types of infrastructure repairs can occur quickly. After injection and expansion, any excess foam is trimmed away to prevent any future blockages within the pipe and the small injection site holes will be filled. With its structural stability, water-repelling qualities, fast cure time, and small project footprint, polyurethane foam makes for a reliable solution to infrastructure repair.

CST Aquires PCG and Opens Midwest Location

Concrete Stabilization Technologies (CST), a foundation lifting and soil stabilization company based in Denver, CO is excited to announce the recent acquisition of longtime ally, Peerless Compaction Grouting (PCG.)

PCG is an Iowa based company that has specialized in concrete lifting and soil stabilization repair since 2005.  With the acquisition, CST has opened a new Midwest branch, located in Waukee, Iowa, and we are up and running strong!

“PCG has an outstanding history of solid performance and customer service. Having worked alongside PCG for many years, we are confident that the acquisition of this company will increase our ability to provide a high level of service to our clients,” stated Clint Mathis, President of CST.

Additionally, CST is pleased to add PCG’s Tommy Russum as Midwest Director, and PCG’s former operations crew.  We are confident knowing that Tommy and his staff add an invaluable amount of experience, expertise, and additional technologies to CST’s team.

The new Midwest location will allow CST to strengthen our service to clients and increase efficiency in completing projects.  This office will be primarily servicing Iowa, Missouri, Illinois, Kansas, Minnesota, and Nebraska.

Concrete Stabilization Technologies, Inc. was founded in Colorado in 1996 and specializes in providing customers ZERO EXCAVATION solutions for foundation lifting, soil stabilization, concrete lifting, infrastructure rehabilitation, water control, and CMP repair.  CST serves public and private entities throughout the entire United States including Departments of Transportation, Counties, Municipalities, Commercial and Industrial clients, as well as Residential customers.