We recently bought a 100 year old house. One of the problems with the house is the kitchen floor was slanted. There is a crawl space under the kitchen as well. I have been working to fix the slant and I have 1 section left to do. My problem is I need to jack up 1 floor joist 1/2 an inch. The main sewage pipe runs directly under the joist and is actually being help up by a metal strap. I am worried that if I jack that joist up 1/2 inch that I may damage the sewage pipe. I am not sure what the metering is but it is original with house so I assume it is Terra cotta. It is a red pipe.

I am not sure if I will be ok to move it 1/4 to 1/2 inch or if I should somehow support the pipe another way. Someone suggested that I put a jack under it, jack up the joist and just restrap it to the joist. I am worried that if I did that, I would puncture the bottom.

Thoughts?

Temporarily support the pipe, remove the strap, jack up the joist and reinstall the strap.

a plumbing supply house will have this type hanger.

you can secure a piece of 3/8 all thread rod to the floor joist and hang the pipe with an adjustable hanger with nuts above and below it. as you raise the floor you can tighten the bottom nut to raise the hanger at the same time.
supply house will have everything you need.

Your REAL problem is that red clay pipe is NEVER hung from the floor. It is supposed to be buried underground. One hundred years ago the joints were made with cement, and if the pipe is shifted, the cement will either come loose, or crack the hub.



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Thank you all for the replies. I will look for that hanger today.

I am guessing that the pipe at one time was under ground. Just a guess. Someone about 25 years ago attempted to dig out the crawl space but stopped once they got to the pip. Or it is possible that there was a problem with it and they dug out the space to get to the pipe. Unearthed it and fixed the problem and instead of burrying it again they just hung it. I really have no way of telling. We talked about just replacing it but we really don't have 12k or whatever it would cost to have it replaced.



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Replace the clay pipe that's under the house, for now. You can worry about the rest later.

Ok so I feel like an @#$%&. I went under house to work on another section. I was looking at the drain and it is not red at all. It is black. Not sure if that changes anything. I will blame the color confusion on lack of light under the house. I can also tell that this pipe was at one time under ground. It appears that at one point there was an issue and they dug it up but never really buried it.

support it from underneath temporarily

jack the joist

rehang pipe

simple

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Need more pictures and information prior to jacking up and re-strapping. You should probably call a licensed Plumber to fix this for you if you still have questions.




Retired UA Plumber Local 230, San Diego, CA

come on.. he is talking about a cast iron pipe that needs support while he jacks up the floor 1/4 inch.
for this he needs a licensed, bonded and insured plumber?
a swivel hanger, some thread rod, a side beam hanger and some 3/8 galvy nuts. he is out of it for 10 bucks, not 300..

quote; swivel hanger, some thread rod, a side beam hanger and some 3/8 galvy nuts. he is out of it for 10 bucks, not 300..

THat will work AFTER he repositions the floor, but not WHILE he is jacking it up.

of course it will. secure the pipe, jack a tiny bit, loosen the lower nut, jack another whisker, loosen the lower nut again. repeat a few times and it's done. he's only talking 1/4 inch.

I have to side with Packy on this; don't make a mountain out of a molehill. Cast isn't clay, so there's no need to panic. I would dig out a little more pipe until you hit the next junction whether it be to cast or clay either one. torquing a cast iron pipe 1/4 to 1/2" isn't ideal, but the joints can usually take a little flexing.