Shoring up old foundation

[treeman]

We have a 110 year old house that we have extensively added on to and remodeled. The last room we have to do is our living room, and it's the oldest part of the house (the original house actually- we gutted it to make it all one big room.) The problem is the foundation and floor. We have a severe slope in the room and the foundation is an old poured footer (very rustic) with layers of brick on top. We originally thought we'd pull out the brick portion and block a new foundationo on top of the old footer and the fix the floor by replacing the old beams and joists (we had to do the floor in our kitchen and it came out great). But, we were also told we could actually build a new foundation alongside the old foundation on the inside of the foundation wall, tying it together with rebar, which I get, but I'm not sure how to shift the weight of the floor from the old wall to the new? Any help would be greatly appreciated!

[Wgoodrich]

I am surprised you found a footer. The 100 year old homes I have rebuilt had brick laid directly on the sod when the house was built. Then the brick was laid up to the bottom of the floor joist. Then a 12x12 beam was laid on the foundation with morticing done so the tongue of the floor joists slide into the 12x12 beam around the perimeter of the house. Most commonly today the mortise toungue entering the beam is rotted off and the 12x12 beam has sections rotted pretty bad.

I have created what was discribed to you as one option to correct the unlevel floor or sinking footer problem. You would go into the crawl space place a 4x4 post horizontal against the bottom of the floor joists and jack up the floor using hydrolic or screw jacks rising about 2" too high. Then place 2'x2' flat concrete pads down on the floor of the crawl space and install a treated post between the pad and the bottom of the 4x4 post being about 2" short of touching the horizontal 4x4. Then lower the floor joists onto those posts. Run this 4x4 horizontal post along the inside of the foundation close to the foundation. Then the house is now supported by the new pads and posts making the floor level. The floor joists if in good shape will cantilever over the old foundation. Then you can shore up the space between the old foundation and the bottom of those cantelevered floor joists. Should last for decades by doing that.

Just an idea

Wg