Leveling a Timber-Framed, 200-year-old House?

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JeffK627

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My house is over 200 years old and timber framed. The South wall (exterior wall) of the living room drops a couple inches from the front of the house to the back, with the low spot being in the middle of the exterior wall just before the partition between the LR and kitchen. I'd like to jack it as close to level as possible, but with 200-year-old 6 by 8s and joists that are mortised and pegged into the main beams, I'm a bit nervous that something will fail under the strain of being jacked. Anyone experienced with this? I was a professional carpenter for 15 years but I've never tried anything like this before.
 
Rubble foundation. It's not actually the midspan, it's one end, which dies into an 8X8 that runs perpendicular and has a vertical 6X8 supporting that end. It looks like there's rot in the member the vertical sits on and maybe in the vertical itself, so one or both will need replacing.

The horizontal 6X8 is about 12 feet long and the 8X8 is about 16 feet long. I'd be raising the point where they intersect, probably using several jacks along the length of each span.
 
You have a basement or crawlspace with how much room? Both beams are load barring to the roof or is one just holding up floor?
 
I own a similar old house and in the process of restoring a second one now with quite similar construction and problems. They used to use those mammoth beams and joists and then cut away half the strength with those mortises.

I tend to try and stabilize things more than lift and straighten or only plan on lifting a fraction of what is called for because of all the other related problems moving the structure up 2 inches in your case may cause. Chances are over the years things were adjusted and fixed based around the slow change taking place.

You mentioned rot and that is the one reason I would worry as that could bring about more rapid changes. Getting a rim beam out and replacing it will be a pretty big job if it all has to come out. Hard to suggest a fix without seeing it but if it were mine I would start poking around trying to figure out just how bad the beam is, being careful if it gets to look like it’s too bad to build up some sort of support structure inside the foundation to help take the loads during inspection.
 
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Bud I haven't done one of these, so I will toss out what I was thinking for your opinion.
Place hanger on the floor joists to the beam to lock them together, Place two new footings inside as close to the foundation as one would dare. Place a new beam under the joists and jack it up slowly, 1/8" at a time, as the beam lefts off the foundation shim the old beam to keep what you get.
When you have it level or as far as you think you can get it shim as much of the old beam that is good and from the outside remove what has rotted with a sawall and replace.
Beam and footing should be sized by an engineer.
 
Many times the plaster&lath has sagged as well, pretty much "set" in that position over such a long time (with subsequent stress cracks)- a little sag at a time. Expect to replace much of the wall finish/adjust doors as Bud said. Tile floors may crack on the grout lines, remove large mirrors on wall, etc. Plumbing drain lines may need new "slope" to work, good time to add intermediate bearing beams for center-span sagging floor joists. While at it, insulate as well- then you won't have to think about that later... http://www.buildingscience.com/docu...dations/?searchterm=insulate crawlspace walls lol.

Gary
 
Hi all, and thanks for your advice.

Plaster and lath are not a factor because I've already gutted the room and the room above it is being remodeled as well. Luckily there are also no widows or doors on the wall involved, and no plumbing either. My plan was to support the 1st floor joists as nealtw suggested, then, after inspecting the rim beam, jacking the 1st floor ceiling as close to level as I can safely get it. I would then replace the vertical support (and rim beam if needed) and install joist hangers on the 2nd floor joists as well. In fact, I plan to put joist hangers everywhere, because as bud16415 pointed out, half the "meat" has been cut out for the mortise and tenon joints. Obviously I won't be looking to move things more than 1/8 inch at a time, and maybe not even every day. I'd ultimately be putting in new studs and resheathing the wall as well, at least partly.

If anyone sees any glaring hazards with this plan, please yell "STOP!!!" at the computer really loud! :D
 
Neal
That’s basically what I would do depending on the problems. The way they built these many times was the rim beam and also sometimes a crisscross beam supported in the center of the basement were 10x10 or something like that hand hewn. They cut a mortise into those big beams and then notched the ends of the joists half way thru like you would do a birds mouth on a rafter only a straight cut. The joists are 3x10 but where they rest in the pockets is only 3x5 cross-sections. That sharp inside corner often splits. Finding hangers to match up isn’t always easy but would help. Under field stones in these old buildings it is sketchy as to what you might find for a footing. In my case the base of the wall was about 4 foot across and the wall tapered up on the outside to about 2 foot top. I felt digging down to put a footing in might disrupt the wall more than it would do good. But then again I wasn’t trying to jack the house up much just enough to close the cracks and or take some bounce out of the flooring above. I did similar to what you suggested and put down a 2x8 treated base plate to spread out the load, 2x6 top plate and then a 2x6 stud wall being very careful to have each stud under a joist and being a very tight fit with doing point jacking or just driving each stud in. if some of the joists looked bowed or bad I used hangers and sister new joists alongside them also. I know using the floor as footing isn’t recommended but I felt it was a good compromise given I knew what the soil was below and the condition of the floor and the fact I wasn’t doing any full heavy jacking at point loading, rather many smaller lift points. The original structure was still doing its job this was just supplemental.

In the OP’s case he is much different he has the upper floors gutted and doesn’t have or has considered the problems jack might cause and he also has the rotted rim beam to replace. Chances are it’s not the full side of the house that’s a problem and he may have to just replace some sections and shim others. Neal’s plan and Jeff’s plan sounds good given he has things stripped out to start. He also is planning to go slow over a longer period of time to give the house a chance to adjust to the changes.

Jeff
If you can post any photos it would be great to see your method and the before and after’s.
 
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