Facts about Polyurethane Foam Concrete Lifting

 
Polyurethane foam is a method of concrete lifting using foam injection lifters. This is an alternative method to mud jacking for raising concrete. Instead of injecting a grout mix (referred to as slurry) into the slab, this lifting method injects polyurethane foam to lift and level the concrete. Both processes of concrete raising are respectable methods, and each have their advantages and disadvantages.
The main ingredients of polyurethane are isocyanates and polyols. The EPA lists these as toxic substances, and both of these are byproducts from petroleum, or crude oil. Because of this fact, Polyurethane is not accepted at recycling centers, and must be disposed of at a toxic waste facility, which can incur additional costs and expenses.
Polyurethane Information:
  • Coverage within 1/32 of an inch can be met or exceeded by cement grout
  • Is very expensive compared to other methods
  • Although injection holes are smaller compared to other methods, mud jacking holes can be repaired using core plug
  • The advantage of covering the concrete evenly to relieve stress can be matched by cement grout if performed properly
  • Lifting capabilities can be matched by cement grout
  • While the claim is that polyurethane repels water from the closed foam cells, cement grout has water repelling characteristics as well
  • Polyurethane is known for not overburdening the soil, but research shows that slab deflection can break down the foam
 
Cost comparison
On average, it takes around 3 lbs. of polyurethane foam to lift the weight that 1 cubic ft of slurry grout will lift. A cubic ft of foam can cost almost 4 times as much as a cubic ft of slurry. A foam contractor may not know how much filling is required under your slab, so they can only guess as to the amount. This can lead to inaccurate estimates that leave you paying more than you thought you would.