Slab Stabilization and Lifting

Concrete slabs that are settling or rocking can be stabilized by injecting structural polyurethane foam into the voids beneath the slabs.  Slabs can also be lifted back to their original position using our Precision Lift process.  Determining which product to use will depend on what type of equipment you have available to you and the size of the project.  Select Resources/How To Procedures for proper installation techniques.

Slab Stabilization

Slab stabilization can be done with our Prime Flex 985 series of products.  These structural foam resins are injected using a two component pump.  For simple slab stabilization, our Prime Flex 985 can be injected at ambient temperature using our FlowMaster 1:1 mix ratio positive displacement pump.  The Prime Flex 985 will flow into the voids and cavities and fill them by expanding up to 20 times (depending on formulation).  The foam is fully expanded and traffic ready within 15 minutes (85% strength).  The rigid foam re-establishes contact between the slab and the sub-grade and is strong enough for heavy traffic loads.

Precision Lift

Often it is necessary to lift a concrete highway, warehouse floor slab, or even a building due to settlement.  This can be accomplished with a two step process.  First, the sub-grade needs to be consolidated.  Voids are filled and loosely compacted soil is consolidated.  This can be accomplished by either compaction grouting or permeation grouting. 

Compaction grouting is a process by which rapidly expanding polyurethane foam (fully expanded in 30 seconds) is injected into the ground.  The foam fills voids in the immediate area and compacts the surrounding soil using expansive pressure.  Compaction grouting can be done with any of the Precision Lift series products, depending on the density of foam the project requires.

Permeation grouting is a process by which a much slower reacting foam is injected into the soil slowly and permeates the soil prior to expanding.  The expansion is limited due to the low levels of catalyst.  Once cured, the Prime Flex "glues" the soil particles together.  Prime Flex 910 is the ideal product for permeation grouting.  Prime Flex 920 and Hydro Gel SX are also good for this application.

Once you have stabilized and consolidated the sub-grade, it is time for the Precision Lift process.  A rapidly expanding foam is then injected directly beneath the slab in short bursts.  By speeding up the reaction with heat and by controlling the amount of material that goes in beneath the slab, you are able to precisely control how much the slab is lifted.  This procedure requires specialized equipment and a well trained technician.  Precision Lift products are designed specifically for this task.