Slab Raising, Do It Yourself
PLEASE READ THIS. The 6 ft x 6 ft sidewalk slab at our front stoop had sunk on one end to a 10-1/2 inch step. It caused people to trip stepping up, and to stumble stepping down. I didn’t want to spend $350 to $400 so I thought up ways to lift the slab and what to put under it. I decided to use heavy-duty C-clamps, a 10 ft. long 4×4 post, and scissor jacks to raise it. And then insert Owens-Corning Foamular high-density foam under the raised slab (from Home Depot or similar store). This stuff is great. It took me about 2 hours once I assembled the tools. Be sure when you buy good hardware store C-clamps that are heavy duty, not those from Harbor Freight or a ‘Made In China’ tool store. A friend who owns apartment buildings had a slab-jacking company pump in expanding foam. He told me that foam does not last. But this Foamular is actually designed to be installed under concrete. It is used in new construction to insulate walls and floors! Don’t try this yourself unless you have proper equipment and take safety precautions. Raise slab HIGH ENOUGH to slide in the foam in manageable pieces. No need to cover the entire area beneath the slab with foam – covering about 1/2 of the area or more will be enough. And NEVER put hands under the slab. Good luck with your project.