Jack sinks into ground as house is lifted.

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Old 06-16-14, 12:36 PM
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Jack sinks into ground as house is lifted.

Hey guys, hope this is the right thread. Ok. Im am trying to lift a pier and beam house (jack up floor and exterior wall) but as I am using my 12 ton bottle jack to lift the house, it is sinking down into the dirt rather than raising the house. What could be the issue? Do I need a more powerful jack? Maybe a 20 ton? Would it help to put a brick under the jack? Do I need more than one jack?
 
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Old 06-16-14, 12:51 PM
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Not a brick a piece of "plywood at least 12x12 to spread the weight. Maybe even two layers if it deforms. A 16x16x4 concrete cap stone but not a paver will also work but is a lot heavier to work with.
 
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Old 06-16-14, 02:20 PM
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I use a 3 to 4 foot long piece of 2x10 with a solid concrete block on top.

Tell us more about the jacking of the house, to what purpose?
 
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Old 06-16-14, 02:28 PM
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It sounds like your jack has plenty of power. You're just exerting more force than the soil can support. You need to give the jack a larger base to spread the load out over a larger area of ground. I use short sections of 4" x 6" posts that I had trimmed off from another project. And like Ray mentioned I also use solid masonry blocks. The 4" thick ones hold up pretty well while the 2" ones are too easily broken under the load.

If you don't have the height to get in enough blocking or if the jack is still sinking with blocking it may be time for the shovel. You'll have to dig down until you get to solid soil. Underneath homes the surface dirt is often just loose dirt tossed in when digging the footers so it's never been compacted. You can also use multiple jacks to spread the load. Splitting the load between two or three jacks can help alot but I still always put blocking underneath to spread the jacks load.
 
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Old 06-16-14, 03:59 PM
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Agreed that you will need to spread the weight around, the 4" x 4" base of a bottle jack isn't enough to distribute the 12 ton lifting force.

However, I'm not so sure that a 12 ton jack will lift the house, floor, and exterior wall.

If you're talking about an empty 800 sqft stick frame rancher, a single 12 ton jack might work.
However, if you are dealing with anything substantially bigger, you may well need another jack,
either another hydraulic jack, or more practically, some sort of iron screw jack or cribbing that is
added to take up the incrimental weight.
 
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Old 06-16-14, 09:11 PM
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the house is 900 square foot and im only trying to lift part (the pier floor is divided into 4 sections (house was added on to several time), each with their own concrete footing. My friend says I can borrow his 20 ton jack to use. That might be powerful enough. But I will try the plywood method.
 
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Old 06-16-14, 10:18 PM
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My friend says I can borrow his 20 ton jack to use. That might be powerful enough
As it has been pointed out it isn't jack capacity. It is the softness of the ground.
 
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Old 06-17-14, 04:26 AM
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A hydraulic jack will either lift it or not although a jack that is too small might blow an o-ring trying. As everyone else has said - you need to disperse the impact on the ground so the jack won't sink! I used a truck screw jack on my 1st mobile home and while it did the job, that jack never did work right afterwards.

When ever jacking up a house you need to take it slow! You don't want to fix one thing only to damage something else!
 
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Old 06-17-14, 04:45 AM
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You are using a beam to lift with at least two jacks (three or more is better). When lifting a room as you seem to be doing you run a temporary beam(4x6 or larger) behind the front edge so you left everything at once. You rotate between the jacks a little bit on each jack.
 
 

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