jacking up joist

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On Jun 6, 3:35pm, snipped-for-privacy@snyder.on.ca wrote:

My point was more about what they are called vs. what one might use them for.
When mm said "I don't know why so many webpages don't call things what people call them." I assumed (yep, there's that word!) that he meant that "so many webpages" were calling 'jack posts' 'adjustable columns' as if they were the same thing.
My response was that they are calling them by different names because they are different items.
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On Mon, 6 Jun 2011 12:46:34 -0700 (PDT), DerbyDad03

FWIW I meant various things. It seems it's not even this thing, which it seems are two different things, but ... well, if it ever did my memory no longer recalls things on this basis, but I know I've seen a bunch of things labeled in the store or in a catalog or webpage with terms on one I know uses. The cube tap is the only thing that comes close.

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snipped-for-privacy@snyder.on.ca wrote:

I'm glad to hear that. I called the manufacturer and they told me the adjustable column would work for jacking small amounts, too. They also said it you don't need to fix the handle in place, it stays fixed because of the weight bearing down on the screw threads. The manufacturer suggested I use a floor jack. But I don't know any reason to, and it's a lot less solidly built.

That's why it's useful to talk things over, it gets you to re-think things. I can extend a sister past the cut easily about 27". Past that I start running into stuff that would make it very difficult, like the toilet drain pipe and pipe hangers. I think I'll attach angle on the front side of the joist, too. And yes I can drill pilot holes that are slightly too small for the screws, so the screws are really tight.
Laura
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On Mon, 06 Jun 2011 15:35:40 -0400, snipped-for-privacy@snyder.on.ca wrote:

I have one ot the other holding up a ceiling I-beam in my basement.
I think there's another I-beam only 10 or 11 feet farther back (in my 22x36 townhouse, but it's sheet-rocked in. At the foot of the basement stairs, there might be another post or column beneath it, but it's boxed in and I'm not sure.
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On Sun, 5 Jun 2011 16:03:56 -0400 (EDT), snipped-for-privacy@grex.org (Graven Water) wrote:

That is EXACTLY what I was recommending. They DO work - very well in fact.

I would put a 1 foot square of 1 inch plywood on the floor to spread the load a bit, and either eyeball it in reference to 2 known plumb surfaces or true it wirh my level. Depending what the top of the jackpost has, I might put a plywood or 2X4 block under the joist - with cleats to hold it centered under the joist and to hold the jackpost centered under the joist, if there was any question about the post possibly slipping off the joist.
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On Jun 5, 4:03pm, snipped-for-privacy@grex.org (Graven Water) wrote:

On the same page that you linked us to are items called "steel floor jacks", so there is obviously a difference between a "steel adjustable building column" and a "steel floor jack".
http://www.lowes.com/ProductDisplay?partNumber=97323-46417-J+C79&langId=-1&storeId=10151&productId=3048053&catalogId=10051&cmRelshp=req&rel=nofollow&cId=PDIO1
My guess is a "column" is meant to be left in place, while a jack is just temporary. As far as operartion, I can't speak to the differences, but if I wanted to jack something, I'd lean towards the item called a jack.
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Graven Water wrote:

I understand that jacking up a joist has to be done over time (weeks) to allow everything to equilibrate. 1/4" doesn't seem like a lot, so you'll probably be okay.
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On Jun 2, 9:33pm, snipped-for-privacy@grex.org (Graven Water) wrote:

That might work. 2x4's will bend though. I have a small bottle jack as well as a floor jack. You can get a bottle jack pretty cheap. If you use a 4x4 it won't bend.
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Attaching the steel angle, if it would give enough support, would be the least complicated way. 2"x2"x 1/8" L beams on each side of the joist.
I'm a little worried that if I put too many bolt holes in that thin 2" x 2" section of joist, it'll crack. The joist is 2" thick and there's 2" of depth left where it was cut. The bolt holes would be coming from both sides, if there are 1/4" bolts (staggered) on each side every 4" or so, that would be a bolt hole every 2" in that section. Yes, I can buy a jack column or whatever if it will do a better job.
I have looked into the other methods and they have problems. If the joist were headered off, the header would have to have like 4 holes drilled through it for the copper water supply pipes. I can't sister it, I talked to the plumber this morning and he said he can't find bathtub drain plumbing that would leave the hole in that joist clear. Apparently they used to make plumbing that would put the drum trap in the space between joists, but he said he can't find it. If anyone knows otherwise, please tell me of it. That was my first thought of course - sister the joist and use drain plumbing that would involve only a small cut in the sister.
Laura
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Again - *can the sag be taken out of the joist by jacking it up* ? It's bent over such a short length, it's likely permanent deformation rather than elastic bending. I know people take sag out of joists by jacking them up. But maybe that works when the sag is over a greater length and it's elastic bending. Maybe jacking up my joist at the bend - the cut place - would just make it crack. Laura
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On Jun 3, 1:14pm, snipped-for-privacy@grex.org (Graven Water) wrote:

Here's how I would proceed. Jack it up so that the top of the joist is just a little higher than level. Then attach angle iron to both sides of the joist with the angle iron firmly against the sill plate. Sandwich the joist tightly. Let the jack down. Basically transfer the floor load from the good section of the floor joist to the angle iron then to the sill.
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Probably doesn't matter if the joist cracks since you plan on adding steel to it. 1/4" is not much in houses.
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On Thu, 2 Jun 2011 21:33:46 -0400 (EDT), snipped-for-privacy@grex.org (Graven Water) wrote:

Borrow or rent a jack-post.
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I realized something nice, which is that I can probably sister the joist, with a 2x10 behind it. The plumbing would have to be gotten out of the way first but I'm almost sure the plumber can redo it so it's not in the way of a sister.
I talked to a home inspector and he said that while attaching angles would work, it would look amateurish and might be an issue for a home buyer. I think he has a point - you want something that not only works, but *looks* like it works, and sistering the joist would definitely look like it's been fixed.
Yes, a jack post sounds much better than brutally trying to reshape my weak, ailing joist with a 2x4 and a hammer :)
thanks for the help, Laura

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However, the sister wouldn't extend the full 15' length of the joist. It would go about 2 feet - or whatever - past the cut part of the joist, and the other end would rest on the sill plate. Does this seem like a strong enough fix?
Laura

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On Sun, 5 Jun 2011 17:38:03 -0400 (EDT), snipped-for-privacy@grex.org (Graven Water) wrote:

I'd sister about 6 feet. Less chance of the joint between the damaged and sister joints failing over the longer distance, and it will look "substantial" to anyone checking in the future. For the small extra cost of lumber and nails/screws involved.
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On Sun, 05 Jun 2011 18:44:52 -0400, snipped-for-privacy@snyder.on.ca wrote:

I thought she was saying there is no room to go 6 feet, only 2.
In that case, or in any case, the holes should be drilled so they are smaller than the screws, OR, iiuc bolts may be used with shallow threads. I presume there are drills not a bit bigger than the size of the bolts, because leeway there is what gets magnified if the sister is only 2 feet long.
BTW, since you first posted OP, I've tried engraving water, but it all just rushes back together again. Is there a trick to it?
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On Jun 4, 10:40pm, snipped-for-privacy@grex.org (Graven Water) wrote:

Oh, do you mean like I said in the first reply in this thread? Who woulda thunk it? ;)

There are more serious problems with the bolted on angles solution than the appearance, but your home inspector is right. It will look like a kludged repair. A major problem with the bolted angle repair is that it concentrates all of the load at the few attachment points at the very bottom of the joist. Joists tend to unzip along the grain in that situation. Such repairs also creep more over time and they bounce more than a sistered joist. These are very bad things in a tiled bathroom.
There are many issues with repairing a seriously compromised joist in a bathroom, but first and foremost is making the place structurally sound. If it's necessary to sister the joists on either side of the compromised joist and install a header to pick up the load from the compromised joist (which would be cut back to allow the plumbing to run where necessary), it's a lot more work, but then that's what you do. I suggested a simple sistered repair on just the compromised joist as I don't know anything more about your bathroom layout, loads, plans for tile/stone, whatever.

Yep. Either way works. If you build temp shoring out of wood, just use a plate at top and bottom, install opposing 2x4s at an angle so they're touching at the point where you want to jack up, and their bottoms are spread a foot and a half apart, then alternately bang the bottoms together along the plate. Just hit each enough to loosen the other one, then switch to the loose one until it's jacked up where you need it.
R
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I realized something nice, which is that I can probably sister the joist, with a 2x10 behind it. The plumbing would have to be gotten out of the way first but I'm almost sure the plumber can redo it so it's not in the way of a sister.
I talked to a home inspector and he said that while attaching angles would work, it would look amateurish and might be an issue for a home buyer. I think he has a point - you want something that not only works, but *looks* like it works, and sistering the joist would definitely look like it's been fixed.
Yes, a jack post sounds much better than brutally trying to reshape my weak, ailing joist with a 2x4 and a hammer :)
thanks for the help, Laura

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I talked to my plumber this morning and he said yes, they can change the plumbing so there would only be a single pipe penetration through the joist for the bathtub drain pipe. (his assistant plumber thought they couldn't). So, I can also strengthen the joist with a metal plate bolted onto it.
Someone told me there's standard hardware, metal plates to strengthen joists. Could someone point me to it? I want something that would please a building inspector ...
I'm also planning to sister the cut area with a 2x10 on the back. The plumber said they can also do the drain plumbing so the sister wouldn't have to be cut.
So it should be good and strong that way :)
Laura

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