Replies

1. 
   J_S | Jun 16, 2000 11:10pm | #2

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   Jim - I've done a form of "mud jacking" with an old style tire hand pump. The cylinder was about 1" in diameter and the top cap was held in by two screws and could be removed. My driveway had settled on a corner of one section. First I drilled a hole in the low area, then filled the tire pump with a very thin cement/water mix, inserted the hose in the hole (make sure the hole-to-hose diameter is a tight fit) and forced the mix to flow between the slab and the dirt. The pressure (pounds per square inch) that is created is high compared to the weight of the concrete and the slab will come up. (A 1" cylinder with 175 lb. of force applied will result in 175 psi pressure.) If your slab is still level, you can just pump the mix into the void and it will set-up.

2. 
   Guest_ | Jun 17, 2000 03:54am | #3

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   is there such a thing? back patio 10x10 seams to have at least a 2-3 inch void between slab and grade.

   thanx for any suggs

   jim

1. 
   Guest_ | Jun 16, 2000 08:24pm | #1

   *What the hell is mudjacking?If you need to pump some concrete under a slab, I saw a home made device for this in FHB May 2000 issue 130.Attached sketch.

3. 
   Guest_ | Jun 17, 2000 03:54am | #4

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   I know a guy who is a mud jack in Colorado - what a coincidence!

   He likes it when malls call him.

   The tire pump may work. Detrmien the area needing jacking and the slab thickness. Concrete is 120 pounds per cubic foot divide the weight by the area and you will know how much pressure you need.

   I am not sure I would do it myself though.

   -Rob