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A friend has a house, probably built in the thirties. Floor joists are 2 X 8 ‘s
resting directly on the foundation walls (crawlspace). The ends of the joists are starting to crush. All I can think of at this point is brace across 4 or 5 joists, jack it enough to sister the joists, then continue around until all joists are sistered. After that little operation is completed, jack it up enough to add the mudsills. Lots of advice and opinions would be appreciated.
Thanks
Scott
Replies
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What about putting some piers and beams under house a couple of feet back from the edge. Jack it up Sister the joists if they need to be and then the weight will be spread out more.
*Are they crushing due to too much weight and not enough bearing area? Or are they dry-rotting due to moisture contact?-Rob
*What's holding this sucker down? Anything besides gravity? Don't try to tell us the joists are toe nailed to the foundation.
*RobI'm presently about 600 miles from this house. Right now all I have to go on are verbal descriptions.I would lean toward a combination of rot and the caustic nature of the concrete. Wood handles fatigue fairly well. I think a load vs. area problem would have shown up earlier. MikeGlad to see you're back. I hope the vacation went well. I think a combination of gravity and tenacity. It's possible that this house could be one that Dorothy and Toto would like :) Another "strange" little factor in this equation is that the end of the joists rest on the gable ends of the foundation. They just don't make 'em like they used to.Scott
*Beware...In the 1800's when stick framing began to replace timber framing, carpenters used to timber framing with ridge beams didn't understand ridge boards. It was quite common to find ceiling joists that were perpendicular to the rafters. Some of these houses are still standing and any kind of change to the structure can cause collapse. I don't know if your floor joists indicate the direction of the ceiling joists, but check it out before you attempt to jack the thing up.
*Mike Thanks for the heads up on that, it might be that old. Friend says ceiling joists run with the rafters though. Still weird that the floor joists are parallel to the ridge, especially since there is a fireplace/chimmney on the gable end, with the joist running up to it. The house is almost a square, something like 33' x 32'. I'm starting to think that it was originally a much smaller house, something like 20' x 32' and that the ridge ran 90 degrees to the direction it runs now. Wild guessing here, but maybe way back owners added on a whole section, demo'ed the old roof and put rafters over the whole thing. The owner is thinking about how bad flooring and how soft the subfloor is in spots. If the decision is made to remove all old flooring, life will become easier. I'll be able to add the mudsills and change the direction of the floor joistsScott
*I think I'd try to bridge across all the joists on one side and jack that whole side at once. Sister all joists as needed, insert the mud sills and let it down in one operation. You need more jacks that way but maybe less time in the long run.However as compared to replacing rotted sills you're adding new height, 3 inches if you use two 2x's. So anything that fastened hard to the crawlspace or basement level like water supplies, wastes, wires, GAS LINES and ducts needs to accomodate 3 inches + clearance of upward movement. Lots of prep and either temporary disconnect with temp patches and then final reassembly or all systems need to be shut down for the project. And even if the sheathing and siding survive all this they will wind up not covering the sills which will need some kind of protective coveringIf the house has been added to there could be a joint in the middle, you're not jacking clear spans from one jacking point to a fulcrum point at the opposite foundation wall. It could buckle in the middle. I guess the alternatives would be a) jacking the whole house as a unit (jacks at two sides and middle concurrently or sister across the middle to make an stable unit), b) sister at the middle and jack one side hoping your sistering holds and it does act as a single unit, or c) clean separation in the middle and lift as two units, but that could play more havoc with walls and in wall utilities and come to think of it floors than any of the other alternatives will anyway.I suppose a real alternative would be to shave 3 inches off the top of the foundation.Good luck.Scott
*DScottMom called me D. Scott every time I got caught. I feel like I'm writing to myself :)I was planning on bridging across the joists and jacking as you stated, however I would probably go in approx 1/2 in. lifts, moving the jacks each lift to raise the house in stages. more hand and knee work, but less chance for structural stress and fewer jacks. One advantage I have is that all the old plaster and lath has been demo'ed and the interior is to wait until the sills are addressed. Disconnect/reconnect of all underground utils should be a minor problem.What I really like about your reply is the last line. Blocking the house in place and reducing the height of the foundation is a very real possibility that I over looked when brainstorming about this. The amount of cribbing required would would be less than doing the staged lifts, and the stress to the structure will be much less. I need to think about this one. I believe the foundation walls are 6" poured concrete. That would be a pretty easy cut compared to some of my options. I could probably cut and remove about 12-13 feet of foundation at a time and never really move the house much, just take the load off the area I'm working. Thanks for the new thoughts Scott (actually Daniel Scott)
*Both a back issue of FHB and one on the TV building shows featured a foundation shaving job. The concrete cutting services have special rigs apparently that are mounted on horizontal rails outside the foundation, hydraulically driven with huge, circular diamond blades. The cutting gear provides quick clean cuts and the rail arrangement for a level and continuous cut edge all around. (A demo hammer leaves a pretty ragged edge. Holding a gas or electric circular saw wth a concrete blade to a level horizontal line is a challange. I'd call the pros.)This way a single 1/4" lift or less might do it and you might not even need to disconnect all utils. Mine is Daniel Scott as well. Dad was Dan too, and as long as I can remember family called me Scott to avoid the confusion I guess ("which one of us you calling...").
*DScottThanks I'll look for the issue. The cheap, labor intensive way to duplicate the rig is to shoot a line and anchor bolt a piece of angle iron to the foundation. Mom always said "D.Scott" would look good when I was an executive. Boy did she guess my occupation wrong. When I got to basic training I found out the Army had no provisions for initial initials so now I sign Daniel S. but go by Scott. I've been out for years, but still do this. Talk about confusion.I get a lot of calls where they asked the switchboard for Daniel and they get transfered to Scott. See yaScott
*I had started an involved message and inadvertantly hit a key that destroyed it. I'll try to reconstruct some of it.The bolted up angle iron handles the elevation variable but leaves you to hold the weight of a big machine (16-18" diameter blade to cut through 6" wall) at 90 degrees to gravity and push it forward at the same time (poured is a lot tougher than block). And you've got to support and guide it dead on when making that first plunge cut (want to try to tweak that 18" blade back onto line when it buried in 6" of concrete?). Alternatively if you start shallow and go progressively deeper (umpteen passes) the guide edge on your saw will start out 8" or so from the wall so you really need a shelf not just an edge.Think about seeing what you're doing through the dust or make provisons for a wet blade and water supply.Have you thought about the difficulty of drilling anchor bolt holes? Will the sheathing and rim be removed to allow space for a hammer drill between the joists? I think I've seen strap type anchors used for retro fitting earthquake rated bracing. Maybe they would work.