Chemical Grouting Can Be Used To Lift Sunken Concrete Or Fill Sinkholes

4 February 2020
 Categories: Construction & Contractors, Blog


You may have heard of slab jacking that uses a cement slurry to raise and level a sunken foundation, but chemical grouting may be new to you. Chemical grouting has been used for decades to lift slabs and stabilize soil. It's especially useful for stabilizing soil near the surface and for use in types of soil where cement grout isn't as effective. Chemical grout is also used alone or with other treatments for filling sinkholes. Here is some information on how chemical grouting works.

Chemical Grout Uses Polyurethane Foam

Polyurethane foam is used for many applications in the construction industry. When it's applied, the liquids turn into foam that expands and hardens. This action is what gives the foam the strength to lift a slab and the ability to fill a depression or sinkhole. This foam is a common type of chemical grout used for lifting slabs and stabilizing soil.

Polyurethane Is Injected Into The Soil

Chemical grout can be injected directly into the soil, but when the grout is being used to lift a sunken slab, the grout is often injected through the foundation. This involves drilling holes in the foundation where the grout can be injected. This type of foundation lifting can be done on residential homes as well as commercial buildings. Multiple drill holes may be required to do the job, and when the foundation is level, the holes are filled back in.

Lifting And Leveling Is Precise Work

There are different types of chemical grout on the market and they have different purposes. They vary in how quickly they expand and harden and in how much weight they support. Some foams are ideal for filling voids in the soil while others are better suited for supporting heavy weight. A contractor might use one type of foam for lifting a sidewalk and another for a commercial slab. However, a lot has to do with control. As long as the rate of expansion is known and monitored with a laser level, chemical grouting is a precise way to level a slab permanently.

The Chemicals Are Mixed On The Spot

Not every type of chemical grout is foam-based. Some are slurries or gels that harden. However, they work in a similar way in that they're based on a chemical reaction. In the case of foam grout, two liquids are dispensed at the same time as they are injected, and as they mix together, a chemical reaction creates the foam. The liquids create a large expanding foam material that gets hard quickly. Once the chemical reaction is complete, the foam hardens to the point where it becomes permanently attached to what it touches.

If you're dealing with a sinkhole or a sunken foundation, your contractor may discuss the possibility of using chemical grout to fix the problem. Chemical grout isn't always used, but it can be a quick and convenient way to deal with soil problems under a building or slab.

Contact a company like A-PAC Pressure Grouting Inc. for more information.