Polyurethane Concrete Raising for Foundation Repair uses a foam material that is injected under the concrete slab. When the components of this material are mixed a reaction causes the material to expand. This expanded foam fills voids and raises concrete, while never loosing its density. After it is installed, it is permanent and weighs about 2 lbs per cubic foot.
After the concrete has been raised, the only visible evidence that the slab has been repaired are the injection sites, though the holes are only 5/8 of an inch – nearly invisible!