Running drain through less than straight studs

[Djarchow]

I have started running the last drain pipe for my basement finish. The bar area will have a small prep sink and a dishwasher. I am under the 2013 UPC and this says a sink with a dishwasher is 2 DFUs which means 1.5" trap and a 2" drain.

I need to run 2 8' sections of 2" abs horizontally through a non bearing wall. I will be required to use stud shoes to reinforce the wall after I am done. I was meticulous in laying out the slope for the pipe and getting the holes centered perfectly in the studs (not easy with a hole saw) and was feeling pretty proud of myself until I tried to slide my 8' section of pipe in and saw that due to crowned studs some holes were off by as much as a quarter inch from the other holes.

I can shove the pipe in but can tell it is binding in spots and bending the ABS pipe some. This seems like a bad long term plan, especially behind drywall and cabinets. Here are the options I see:

1. Rather than use a solid 8' section of pipe, use couplers to give me some ability to jog in and out at the sections that are binding. I will have to use couplers in the other section of wall anyway. I could either glue or use Ferncos.
2. Using a laminate router or a sanding wheel on a drill, clean out the area that is binding and hope my inspector doesn't look too close behind the stud shoes and see the extra I have hogged out.
3. Get shallower cabinets and run the pipe behind them
4. Lose the dishwasher as the sink will be fine with 1.5" which will fit with no issues. Wife won't be happy about this but is mostly just for glasses, pitchers etc.

I don't really want to reframe the two walls as 2x6 since at least one has a door opening in it and I really really don't want to bust up concrete.

Any suggestions?

 

[Reach4]

I am not a plumber, and I expect your choices will work fine.

But suppose you wanted to be extra careful and over-build? I am suggesting where you hog out the hole, also use a piece of 2x4 where you have cut a hole perfectly in the drill press. Sister that in place with the hogged studs using screw and glue after the pipe is in place and there is no pipe stress. Overkill I am thinking, but overkill has its advantages at times.

 

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[Cacher_Chick]

It may be easier to just to cut out a couple of the worst offenders and replace them with straighter stock. Sometimes you can turn the stud around and it will line up better.

 

[Djarchow]

Reach, Cacher_Chick,

Thanks for the replies. I am going to check them tonight and will look into just replacing the worst studs. I am nervous about getting it right since the holes are only 1/8" bigger than the pipe. So not a lot of wiggle room; not mention seasonal movement and I have heard enough horror stories about ABS cracking over time. I know that was a bad batch but better safe than sorry.

Thanks again!

Dennis