Replies

1. 
   rjw | Jul 19, 2009 08:23pm | #1

   I suspect he's already using some sort of padding to spread the laod for the jacks.

   If he uses an industrial size dehumidifier - like the disaster recovery companies use, it might go quickish.

   Esp if he also uses some fans to keep air moving over the areas that need to dry.

   Depending on how big the crawl space is, he might want to plastic over areas removed from where the jacking needs to be done

   ---

   "Ask not what the world needs. Ask what makes you come alive... then go do it. Because what the world needs is people who have come alive."

   Howard Thurman

   ---

   http://rjw-progressive.blogspot.com/

1. 
   REempire | Jul 19, 2009 09:21pm | #3

   Thanks for taking the time to reply. Does "quickish" mean days or wks? The house is 1700-1800 sq ft ranch if that helps.

2. 
   WayneL5 | Jul 19, 2009 08:38pm | #2

   Yes, it's possible.  That's the fundamental theory of any structural foundation, to spread the load over a sufficient area to carry it without settling.  In addition to covering enough area the pad has to be thick enough so it does not itself crack from the load.

   The concrete must also set up long enough to attain sufficient strength.

   I don't know enough to recommend a size, though.  If you call a soils engineer with the estimated jack load and a description of the soil he just might be able to answer your question over the phone in a couple of minutes.  Maybe even for free.

   If you can get them its probably easier and faster to use heavy timbers and plywood rather than concrete.

1. 
   REempire | Jul 19, 2009 09:23pm | #4

   Thaks for the input. Had not thought about the thickness of the concrete.

3. 
   seeyou | Jul 19, 2009 09:51pm | #5

   I've jacked foundations up using solid CMU's.  Put one on the ground and start jacking. It'll push into the ground. When it pushes the thickness of the block, add another CMU and repeat. After several blocks the ground beneath will be compact enough to carry the force.

   http://www.quittintime.com/      View Image     

1. 
   REempire | Jul 19, 2009 10:35pm | #6

   Thanks for the reply. It'll compace even wet ground?

1. 
   brucet9 | Jul 19, 2009 11:09pm | #7

   Really wet ground, in other words mud, will flow away from that CMU instead of compacting, but if the wetness is from the surface down, eventually you would reach firmer ground.If the wetness is from a subterranean water source, you would have a whole other situation on your hands.BruceT

2. 
   seeyou | Jul 19, 2009 11:13pm | #8

   Or push it out of the way until it reaches dry ground.http://www.quittintime.com/      View Image     

1. 
   REempire | Jul 20, 2009 12:32am | #11

   Thanks.

4. 
   coonass | Jul 19, 2009 11:25pm | #9

   RE,

   When the ground is soft we use 6x6 cribbing to build a base to jack off of. If there is not enough head room we use a double layer of 1 1/8 plywood. A 2'x2' square will support a lot. You could go bigger.

   KK

1. 
   REempire | Jul 20, 2009 12:31am | #10

   Thanks for taking the time to reply. Good info.