Polyurethane Foam Concrete Lifting

History of Polyurethane Foam Concrete Lifting (Polyjacking)

Polyurethane Foam Concrete Lifting

• Concrete lifting polyurethane foam (foamjacking) was first developed and introduced in the 1980’s
• Polyurethane foam concrete lifting method has been made more available and used more since the late 2000’s.

Polyurethane Foam Concrete Lifting Method Process

• 5/8” holes drilled into the concrete are approx. spaced every 24″ – 36″ feet in a grid pattern depending how the concrete is sunk.  Depending how much the concrete is sunk, 2 rows minimum or more is put into the concrete to properly raise and fill the concrete pad.

Hole pattern layout for sunken driveway, 3 rows of holes are put into the driveway to properly raise the concrete and fill the voids. Most top sections of driveways take 3 rows of holes and at minimum 2 rows of holes for driveways with very little settlement. Concrete raises in distances and as you raise the driveway 2-4 inches it raises the entire top section. Why 3 rows of holes are put into the driveway to raise the top section of the drvieway and fill the voids.

• Injection ports are then placed and tightened into the 5/8” holes.
• A 2-part liquid is then injected underneath the concrete, causing a chemical reaction and expands the polyurethane foam material.  The foam expands and fills voids in the area being injected, causing the concrete to lift.
• The concrete is raised to original height and voids are filled best as possible. Then the job is cleaned up.
• 5/8” holes are filled and patched with a grout.

Polyurethane Foam Material

• Polyurethane foam is an expanding material.
• Lightweight.
• Sets quickly and can be fully set within 15 minutes.
• Made from recycled foams.
• Polyurethane foam is a high density engineered material that is designed for different applications depending on the density of the foam.

Polyurethane Foam Concrete Lifting Tunnel Grain Elevator. 4lb commercial grade high density foam was used for this job.

Polyurethane Foam Concrete Lifting Method Facts

• The spacing and the number of holes put into the concrete are the same as mudjacking to properly raise and fill the voids best as you can underneath the concrete. Without putting in more 5/8″ holes into the concrete large voids can be left under the concrete pad.
• Higher risks over lifting the concrete slab because of the expanding polyruethane foam material and you can’t see underneath the concrete slab to know how much polyuerthane foam material to inject to fill the voids making the process of filling voids extremly difficult with out over lifting the slab and cracking it.
• 50% to 80% more in cost than a mudjacking job if done properly and voids filled best as possible, because of the material cost and extended labor times. When doing a poly jacking job patients must be expressed because of the expanding polyurethane foam material while installing the foam material and trying to fill voids with out over lifting the concrete slab.
• Harder to predict material cost when raising concrete with polyurethane foam because of the unknown void filling process.
• Polyurethane foam concrete lifting method can be cleaner than mudjacking while doing the job, but if the polyurethane foam material comes out of a crack or gap it can be damaging what ever the foam material gets on causing a permanent stain and having to replace what ever the foam material gets on.
• There is less control of the concrete because of expanding materials, which makes it more difficult to raise the concrete and fill voids. 
• Polyurethane foam set times are fast with in 15 mins.  This can be a disadvantage while raising the pad because it doesn’t allow the concrete to float. This can cause more stress on the concrete while being raised causing more cracking and in some cases original elevation can be harder to accomplish.  It can also be harder to tilt and adjust concrete panels to match trip spots.
• Polyjacking can be a good solution for interior concrete slabs with limited access 
• Polyjacking can be a good soluton for heavy commercial and industrial slab.
• Higher chance of overlifting Residential concrete because of the light weight concrete being lifted making it harder to control. The expanding material can make the residential concrete overlift by injecting too much foam material underneath the light weight residential concrete slabs. The Void filling process can be extremely difficult leading to overlifting of the concrete slab or voids not being filled properly because of this.

Summary

Polyurethane foam concrete lifting method (Polyjacking) has its place in the concrete lifting industry. It can be a good solution for raising sunken concrete but does have its limitations and the job should be accesed by a professional experienced in All concrete lifting methods if polyjacking is good fit for the concrete lifting job that needs to be done. It takes patients and proper procedures to be followed to raise the concrete with a expanding polyurethane foam material. Voids under the concrete must be attempted to be filled best as possible, as concrete lifting is not just about raising the concrete its also requires filling the voids underneath the concrete slab to insure a proper repair is done.

Polyurethane Foam Concrete Lifting Trailer Equipment