TOo much slope for shower drain?

[jimmydaux]

Hello all!

I have a quick question. I am roughing in a new shower drain and tieing into an existing 2" line from my washing machine. I was very tight on room between two floor joists, and couldnt set the trap lower due to interference with the 3" line below there the trap would be. As you can see from the sketch of what I have, I used a combination of elbows to get the loop where it needed to be. Im just curious if I am going to have a problem with the amount of slope. The loop is about 30" long before it ties into the existing 2" line. The problem is that is drops about 4" to 6" in that short distance. It seems to be adequately vented. Currently I have no siphonage issues when I have the washer draining, neigboring sink running and toilet flushing. Does anyone see any issues that may arrise in the future before I start my shower pan and tile process?

I appologize if the picture is hard to interpret. I have floor sheeting down already otherwise I would have just taken a real picture.

Thanks in advance!!!!

Jeremy

 

[Jimbo]

Let me say first, this will probably work ok. And there really is no such thing as too much slope.

Now, there are some things wrong "by the book"

The UPC doesn't allow tieing into the shower lateral. And you are wet vented off the washer. That is probably a no-no.

That big loop MIGHT be a hair catcher, and the extra slope will work in your favor. The code would require you to have a cleanout at such a change of direction. But how do you do that under your floor?

Let's see what some of the other boys have to say about all this.

 

[Sponsor]

 

[jimmydaux]

The loop is fairly gradual with no 90's. Most of the elbows that make up the look are 45's or 22 1/2's. If there is something that should be done to this id much rather do it now than down the road. If anyone thinks it is entirely unacceptable, Ill pull it apart and take a picture for input on how it should be run. Thanks for your feedback so far

 

[Basement_Lurker]

wet venting a shower with a washing machine is asking for trouble. slope the piping properly as there are reasons why grade is to be maintained @ 0.25"/ft

 

[Geniescience]

double offset to get around the 3" obstacle. P trap at a lower height. Tee in at the bend. If it fits.

 

[hj]

1. The shower is NOT properly vented, because the velocity of water flowing PAST the shower inlet can create a venturi effect and create siphonage.
2. your drawing is not clear as the relative elevations of the pipe and the trap, but if the drop is more than 1 1/2"-2" WILL create an "S" trap, (this time because it would not be be vented at all), which CAN self siphon, even without the washer flow helping it.
3. The use of the various elbows is immaterial, as is the DEGREE of slope. The total amount is what creates the problem.