Foundation compaction grouting

[m1208]

I am working on a one-story structure on concrete-slab floor in California. A portion of the foundation and the concrete-slab floor has settled and some of the walls have developed cracks. We are planning to raise the foundation and the concrete-slab floor (approximately 2 inches) to stabilize the foundation. In the past we have retrofitted this type of projects using "Compaction grouting" method, which uses actual cement grout. The contractor has proposed using "POLYURETHANE FOAM " instead of "cement grout". I did some research on the foam and some people were not happy with it. Is the "POLYURETHANE FOAM" as good as the traditional "cement grout" for densification of the soil and stabilization of the foundation?

 

[mjr6550]

IMO polyurethane injection is a good substitute for mud jacking-filling voids below a slab. I have never heard of it being used for compaction grouting. Maybe it is a legitimate method and maybe it is just someone with a franchise winging it.

 

[m1208]

Thanks
Can polyurethane injection be used to lift the exterior wall foundation of a house (approximately one inch)? The vertical gravity load on the exterior wall foundation is approximately 1000 pounds per square foot.

 

[mjr6550]

I've only seen it used for lifting slabs. One company I looked up says lifting forces up to 6000 psf are possible.

 

[oldestguy]

I used it once for raising a heavy masonry wall (around a prison) and tilting it back to vertical, but the injection points were about 5 feet below the foundation.