4" closet bend or 3" street 90?

I am trying to install a toilet waste line in a 2x10 joist bay. My horizontal run is pretty long (almost 20' fortunately goes into a dropped ceiling area near the end, so I will have enough slope), so I need to keep the 3" pipe tucked up as high as I can near the toilet. I was planning on using a 3" street 90, but my plumbing reference book keeps mentioning a 4" closet bend.

When I look at a 4" closet bend it looks like it would do a much better job of moving the waste, but it is also much deeper than the 3" street 90, which means I am not going to be able to meet slope requirements.

Is the 3" street 90 adequate? or do I need to find an alternate plan?

I'm not a pro, but I'm pretty sure the 3" will be fine. Have you planned the vent?

yup, breaking off with a 3x3x2 Y.

3" is fine for a bathroom. I would use it for that.

remodelbob said:

yup, breaking off with a 3x3x2 Y.

Click to expand...

Straight up or 45 degree or more.

How do you guys make these darn computers make a degree sign?

not enough room to go straight up. going 45 degrees.

remodelbob said:

not enough room to go straight up. going 45 degrees.

Click to expand...

That's OK, I take it you can't make a degree sign either.

They must type it first then post it?

bend

Uses the spigot closet bend. you can cut the riser off at the floor line after the tiling is complete. It will be "shorter" than a 3" street elbow, just be sure to have enough of the spigot below the floor level so the closet collar/flange will slide down to the floor.

Like hj, I also use a closet bend for that reason.
The local hardware stores carry an ABS 4x3 spigot closet bend that will take a 4" closet flange.
If I really want to make it tight, I can trim a bit of closet flange hub away to let the flange drop down farther.

one option would be to use a 45 degree closet flange and a street 45. that would keep you pretty high.