running waste line

[TimWhalen]

I appreciate everyone's input on my issues with running PEX to my new upstairs bathroom (separate topic).

My question now has to do with running drain lines from the fixtures to the main waste line. I have to get through true 2x12's in the floor. Of course, I will try to route my lines to minimize the cuts, but I will have to fit some 2" PVC through the 2x12's.

The 2x12's are 16" on center. Do I just cut lengths of PVC and glue them back together once they are run through the joists? Is there a flexible alternative?

What's the best advice for cutting the joists and maintaining the required slope? I am concerned about weakening the structural integrity of the joists.

[rjbrown2]

You could check the latest edition of the International Residential Code (IRC) for the allowed places and dimensions when drilling and notching floor joists. In the old copy I have it is Section R502

[David Meiland]

Definitely find and follow the code requirements for drilling and notching framing. You will find that you can run a line of 2-1/2" holes for a 2" pipe through 2x12s without much problem, including the needed slope, as long as you don't need to go too far. You will need to plan carefully, so that any traps below the floor work out and aren't too high or too low.

Sometimes you need to cut short pieces and use a bunch of couplings. On a few occasions, I have made access from outside or from the adjacent room so I could slide in a single piece. Depends on what you're doing...

[mlparham]

Please hire a plumber for waste lines.

[Marc]

Please hire a plumber for waste lines.

Yeah, that's the smart move but if you're determined to do it yourself, do your homework on allowed notching and boring and perhaps oversized your holes to make it easier to slip in longer sections of pipe.

Marc

[ghentjr]

Run it parallel to a joist to where the joist meets a wall and box it in on the wall under the perpendicular joists.