I'm fed up trying to get my p-trap and riser plumb. Please help me before I spontaneously combust!

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So, I am remodeling my shower (using the kerdi kit) and I'm having the hardest time ever (ever) getting this p-trap/riser plumb. I feel like an idiot. I had to rebuild the p-trap for whatever reason, and to my dismay, the damn thing didn't come out straight. Here's an album of images that shows whats going on.

The third image (which is after I'd removed everything out of pure rage) shows my main problem: the pipe comes out of the joist at an angle, which I'm assuming is for drainage purposes, but since it comes out like this, even with the built in slope in the PVC, the riser doesn't come out straight. It looks like it's straight, as you can see in picture 1, but it's not really straight, as you can see in picture 2. I need it to be straight enough that it rests on the foam inserts, since i'm using a kerdi foam try. I strapped it down and everything.

What can I do to remedy this? I just dont see any way. I'm hoping I'll have enough room to add a coupling in before the p-trap, because if not, I'll have to start before the pipe comes in through the joist.

Please help me! I'm gonna post this everywhere I can think of, haha. I'm going to give it one last shot. Thanks!
 
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FullySprinklered

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Listen, you need to get over the 1/4 " per foot slope requirement that close to the shower drain. Give yourself a break and get the drain fitting flat, then pick up the slope on the other side of the joist. Nobody expects you to goober up the shower pan to try to meet the slope requirements over that last foot of piping. Your slope looks excessive anyway.
 

Tom Sawyer

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I'm always happy when folks without plumbers licenses weigh in. Lol
 

Jadnashua

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A couple of 1/8 or 1/16th bend elbows can overcome nearly any angle to get the riser straight. They could be either in the outlet of the p-trap or on the riser, itself, depending on how much height you actually have from the trap itself to the drain. This is not a unique problem with that drain, either. Any of the thinbed, large diameter drains must be installed on a plumb riser or you'll have issues. A banded coupling can let you adjust a degree or two, and adjust the length maybe as much as 1/4" or so. Ideally, you'd have the pipe all the way to the stop in the middle, but it won't kill anything if there's a slight gap. Just don't make it any bigger, or you'll have issues with it trapping hair, etc, and especially if it's before the trap, smelly.
 
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So do notch the joist? I'm open to anything. I can work from before the 90 bend behind the left joist or after it. I was specifically told not to put in a 22 1/2 coupling to compensate for the slope.
 

Jadnashua

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You do not want to use elbows to tweak the slope, but you can use them to adjust the vertical so it goes exactly where you want it, and the last bit of pipe is perfectly level. Now, that won't work if you do not have enough height to do that. As long as you do not create a flat spot or dip in the drain pipe, you can use them to adjust the horizontal placement, too. Even with pictures, it's hard to say without being there. When you're dealing with a large diameter drain (well, any drain where you want the grate level), you really do need the riser to be truly plumb. Banded coupling(s) will let you adjust things a little bit rather than a glued joint.
 
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Nooooo way!! Hell yeah terry, thanks! Now if only it stays like that once I glue it (not likely)!
 

Jadnashua

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Depending on the age of the cement you are using, the weight of the pipes, how much you use, it can take a varying time before enough of the solvent evaporates to make the joint solid...just hold it or support it well. Keep in mind that since the sockets of the fittings are tapered and interference, and the cement acts like a lubricant, it will want to push the joints apart until the cement takes hold.
 
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Oh, I meant, I hope its level and stuff once everything is pushed together with cement and set. I learned how long it takes them to set the hard way, lol. I'm pretty nervous that it wont be level when its all together with cement. This is one reason I just hate the hell out of PVC--i feel like i cant tell what i'm gonna be doing all the way; just kinda.

Question: why is the way I'm doing it working? Shouldnt I still have the same problem i had before (with it angling upwards)? Just seems like I added that 22.5 and boom! it suddenly works.

Question 2: when I attach that 22.5 to the stub I have left, should the stub be cut square relative to the floor, or to the angle it is exiting the joist? Does it even make a difference? I tried compensating for an angle (a while ago) by cutting it square relative to the thing I wanted it to be parallel with, and all it did was just catch the higher lip and keep the angle going the way it was.

Hopefully that made sense...I appreciate all the advice you guys have given me.
 

Jadnashua

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WHen cutting pipe and the fittings they are designed to go into, the pipe's end should be square to its length.

WHen you add an elbow, you can compensate a degree or two. Plus, something like a 90-degree elbow is still designed to allow for the nominal 2-degree slope.
 
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