DWV rough in help

To all,

I've got a few questions regarding the attached drawing. I'm planning on roughing in a toilet and a sink. The toilet is on one level and the sink will be standing on a slab 40†below the toilet. I'll have a 40“ high - 12“ block wall separating the two fixtures with a 2 x 4 framed wall on top of the block wall.

I'm planning on using 3" pipe from the toilet and using 2 - 45 degree elbows to get down to where the sink drain goes through the block wall. Somewhere below the second elbow I’ll install a 3x3x2 wye and vent it back through the block wall to a 90 degree elbow and then up to the 3†vent through the roof. Are there any requirements that the 2†vent pipe must be at a specific angle (toward vertical) going back to the block wall? Finally, I'll connect the 2" sink drain into the toilet drain via a 3x3x2 wye.

In terms of the venting the sink, can I use a 2" sanitary tee in the middle of the block wall to vent the sink? Is there a problem with the 2" tee being too close to the sink trap? I read somewhere that this might not be the proper use of a sanitary tee?

I realize I can put a clean-out either before I exit the building or immediately after exiting the building but does anyone see a problem if I install a 3x3x3 wye below the toilet and create a clean-out behind the toilet? Is that a bad idea?

As you can see, I'm proposing running my main drain line entirely on the right side of my block wall - mainly because the ground will already have been excavated and should ease the plumbing rough-in and provide plenty of drop for the drain. The other choice is to take the more direct route and drop the drain and soon as possible and go through the block wall, and under the lower slab. Is there a big advantage of one way versus the other? Is one more problematic than the other?

And finally, are there any concerns with running schedule 40 pipe immediately adjacent to the block wall (in the gravel, under the slab)? How deep should the pipe be buried in gravel below the concrete slab?

Sorry about being so long winded - any help is greatly appreciated.

Reid

You can run the 3" to the water closet ,install a 3x2 combo for the sink and the sink vent will wet vent the water closet. The way you have it the vent for the water closet is a dry vent and will not pass code. A 2" vent will pass code as long as the building has a 3" main stack. The water closat will ack as a clean out and a 2ND C.O can be installed outside or were the drain makes a 90.o turn

Thanks very much Bud1300!

However, I'm a little confused by your advice. Are you suggesting that I should replace the 2" sanitary tee (located in the block wall) with a 2x3x2 wye (3x2 combo ?) that could directly vent a 3 inch pipe to the roof from there? If so, that would totally eliminate the 3x3x2 wye I currently have to dry vent the toilet - right? This is implying that I can get away with a single vent for both fixtures - right?

Do you think I'll have any problem with the main vent being too close to the sink trap like I explained earlier?

Also, is it kosher to be drilling 3" holes in the top/bottom plates of a 2x4 stud wall for the main vent? Or do I need to frame with a 2x6 wall?

Reid

no, a wye and and a combination are two different things...the combination (3") will only have a 2" leg sweeping off...

Ok - but does the combo replace the 2" sanitary tee? If so, do I use the 2" as my vent and will it be a sufficient vent for both the toilet and the sink?


Any comments about the vent being too close to the sink trap? What about the 3" holes in the stud wall?

Thanks again for the help,


Reid

Bud1300,

Thanks for responding to my post. You state that I should use a 3x2 combo - is this in place of the 2" sanitary tee I was proposing using for the sink vent? I'm not familiar with that sort of fitting - is it a straight through 3" with a 2" sweep? Looking at my drawing - would this be going in my block wall? The 2" fitting would be my vent - right?

Are you implying then that the one vent is enough for both the toilet and the sink? They are only approx. 4 foot apart.

I believe you're also suggesting that I do not need to add another clean-out behind the toilet - right?

Any help is greatly appreciated.

Reid