Underpinning Basement Standoff Jacks / Supports For Inside Acess Only?

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Here's what the a portion of the wall looks like. The full depth basement walls are the same material.



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There are a million done just like Neal’s video around here. It is a matter of how brave you are how far you dig back and trust soil to hold the wall up. You always end up with a shelf. The OP wants to hold a section at a time up and slip a new wall and footer in below it.
 
His wall is mortared, why would you not treat it like brick?

Well it is 100 plus years old and lots of this mortar was pointed in from the inside and outside to seal it up. It is an unknown.

The only way I would trust doing something like this DIY. Stay with me I’m going to paint a mental picture here.

First crib the joists and jack up and take the weight of the house mostly off the foundation in the area where you will be working. Then drive steel under the lowest stone and past the outside of the wall a good 2 feet. steel could be ½ x 2. After getting an area large enough to work on done then drive a piece 3” angle iron in on top of the steel. I would space the steel every foot. I would then weld the angle to the bars I have driven in. now I would build some 45 degree bracing to run from pockets in the floor backed up with a good foot and weld or bolt that to the angle. Now you have a section of the wall braced in place from falling and the rig you just built is only holding the stone not the house as well. dig out that section and place footing and build wall. move over 4 foot and repeat.

The problem in doing this is you assume the bottom row of stone was laid flat. Every time I have ever worked on field stone I always found they found some bolder they put in first and who knows if they didn’t dig it down a little to get that one set in. with stone there is no reason to start with a flat footing as you correct all the way up the wall and end flat.

I have seen a lot of old places taken down and when they get to the basement walls they roll them in a bury the stone. It never looks like it is too hard to do.
 
Well it is 100 plus years old and lots of this mortar was pointed in from the inside and outside to seal it up. It is an unknown.

The only way I would trust doing something like this DIY. Stay with me I’m going to paint a mental picture here.

First crib the joists and jack up and take the weight of the house mostly off the foundation in the area where you will be working. Then drive steel under the lowest stone and past the outside of the wall a good 2 feet. steel could be ½ x 2. After getting an area large enough to work on done then drive a piece 3” angle iron in on top of the steel. I would space the steel every foot. I would then weld the angle to the bars I have driven in. now I would build some 45 degree bracing to run from pockets in the floor backed up with a good foot and weld or bolt that to the angle. Now you have a section of the wall braced in place from falling and the rig you just built is only holding the stone not the house as well. dig out that section and place footing and build wall. move over 4 foot and repeat.

The problem in doing this is you assume the bottom row of stone was laid flat. Every time I have ever worked on field stone I always found they found some bolder they put in first and who knows if they didn’t dig it down a little to get that one set in. with stone there is no reason to start with a flat footing as you correct all the way up the wall and end flat.

I have seen a lot of old places taken down and when they get to the basement walls they roll them in a bury the stone. It never looks like it is too hard to do.

The problem with cribbing or temp walls holding up the house is working room, dig it out first or after, getting beams in there. Taking the weight off the foundation may not be a good idea, if the wall has out side pressure leaning in.?????????

And with the best laid plan, do the corners first or last?????
 
The problem with cribbing or temp walls holding up the house is working room, dig it out first or after, getting beams in there. Taking the weight off the foundation may not be a good idea, if the wall has out side pressure leaning in.?????????

And with the best laid plan, do the corners first or last?????

My opinion at first is really the one I feel strongest about and that is do it the tried and true way with the 3 or 4 foot shelf. You can still walk around when done and store things and it is next to impossible to make a stone basement into useful living area. It is great for storage etc and to walk around to service pipes and a place for the furnace and tanks etc. I would take the same amount of money and effort to do more than that and build a nice building at ground level if I had the room to use for other things.
 
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