I am installing a new vanity and need to raise the waste exit pipe about 6 inches higher in the wall and 6 inches closer to the stack. Is it acceptable to cut out a section of the current pipe and use 90 degree angles to raise the pipe and move to the right in the wall? Will it cause any problem with the proper venting? Thanks.

Show us a picture or a drawing of what you propose to do. The trap arm cannot turn down before it reaches the vent.

I hope this shows up:46984

Sorry can't see it. Make a post, click on "Go Advance" button below posting block, click on "Manage Attachments", Browse and find pic (in JPEG format), select, upload and click done.

I'm showing that the file is listed below... sorry to be such a problem! I redid with your instructions and it appears the same... maybe I got lucky this time! Thanks.

I see the pic. Edit your last post and reduce the size of the pic. Makes the post to hard to read. Give me time to make a drawing.

Sorry.. I'm still learning this tool! I downsized it... hope it's readable

Sorry.. I'm still learning this tool! I downsized it... hope it's readable
Yes that's great, post is now a lot easier to read.

Cut the stack as shown in the drawing. The best tool for cutting the pipe is a PVC wire saw. Just stranded wire with finger loops. Cuts by heating the pipe. Don't cut to fast, or pipe will stick back together.

The piping you have is ABS. You will probably have trouble finding ABS pipe and fittings. Replace with PVC.

Join ABS and PVC pipes with Fernco shielded rubber couplings

I assume you want to move the pipe up because of a conflict with shelving. Before doing anything make sure that your are not moving it up to high and that there is enough room under the sink for the trap. Sit sink in vanity, connect tail pipe and trap. Measure distance to floor to insure that you have proper slope of trap arm. The worst thing you can do is get the drain to high.

You're awesome! I went to HD to get parts to replace the sanitary T, but a plumber there suggested I use the angles to raise the pipe to avoid having to re-drill the studs. Can I use the same ABS pipe (shortened) to insert into the new T, or would you advise replacing the entire length of pipe with PVC? Also, is there a reason that the waste pipe must come out between the supply pipes, or can it be to one side of the cold water pipe? I do have a wire PVC cutter... use regularly for sprinkler pipes!

but a plumber there suggested I use the angles to raise the pipe to avoid having to re-drill the studs.
That was no plumber, that was a shelf stocker. The drain pipe cannot turn down (beyond the normal 1/4" slope) before it reaches the vent pipe. If it does that turns the "P" trap into an "S" trap which is not allowed.


is there a reason that the waste pipe must come out between the supply pipes
No, water supply pipes can be anywhere you want them.


. Can I use the same ABS pipe (shortened) to insert into the new T,
Yes, if you can find an ABS double tee. ABS and PVC are not compatible. There is an all purpose glue that will bind the two but the expansion and contraction rates of the ABS and PVC are different. So not recommended. That the reason for the Fernco shielded couplings.

Can you purchase a ABS double sanitary tee? And can you find ABS pipe. Usually it is the pipe that is hard to find.

Thanks again. The plumber was actually shopping in there, not a HD employee... he should have known about the S... oh well. Based on what you said about abs and PVC, I think I'll just replace everything with the pvc and then the only place where the ABS and PVC will meet is where I'll use the Fernco shielded couplings. You've been so incredibly helpful... I am so grateful! Thanks again!

HI ALL.

I would leave the double sanitary tee in place and cap the left drain line with an appropriate cap... leaves the sink on right as is which by your drawing appears to be OK. Install a single sanitary tee at the correct height using just one clamp (bend rubber back on itself) for the new sink... ;)

Mark

Thanks, Mark! Actually the right sink needs to be moved, as well. I just didn't draw it in the picture. Another question I'm sure you can help me with: The bathroom is second floor and the stack goes through the attic to the roof. It is 2" ABS pipe. How much will I need to anchor the pipe before cutting it?

. How much will I need to anchor the pipe before cutting it?
Shouldn't have to worry about that. It is real light weight.

If you can find a ABS double tee, and two 2" ABS caps, you could cut the 2" lines close to the studs and install the end caps. The cut the vent pipe, which looks to be 3" (could be 4"). If, after cutting, see if the vent pipe that goes to the attic will lift up about two inches (it probably will), you could glue in a the new ABS double tee. That would be the most economical and least amount of work. Saves you buying 10 foot of 3" PVC of which you only need a couple feet.
Probably have to go to plumbing supply to find ABS double tee and end caps.

Call plumbing supply house, ask if they have 3" (or 4") double tee and 2" pipe caps. The will probably have end caps. May or may not have double tee. Cut the vent pipe at the proper height. See if vent pipe will lift.

If you can't find the ABS double tee, you nay as well cut all the old stuff and replace with PVC as previously discussed.