I am preparing to install some drains in a concrete slab and wondering if my attached diagram looks correct. This is a single story home and I am converting the utility room. I am ready to start but I was hoping someone with more knowledge than myself could please verify that everything does look correct. I appreciate any assistance on this.

I work under UPC. Under UPC it would be incorrect ( Not enough vents ). Pipe sizes seem to be OK. However, let's wait for our Experts who work under different Codes to offer their opinions. Thank You.

Thank you for the prompt reply. There is another vent. Where the drawing leaves off, it ties to the main which is also vented. This is a single story house so I'm not sure if you still call it a stack.

Hi Wkendwarier:

No matter what code you fall under this is not correct... as Milo pointed out. It is also difficult to draw this up for you with the drawing you presented as it is hard for me to tell how the fixtures actually lay out... ;) Draw this out in terms of a bathroom with fixtures ONLY and then draw the washer and the kitchen sink in so I can appreciate how things are in relation to each other... then we can draw something up.

As it is now, you have no vent on the washing machine, the toilet, the shower or the kitchen sink. All these fixtures require a vent.. either individually or perhaps you can use a 2" lavatory vent to act as a wet vent for the shower and the toilet, but I need to know the layout better... ;) The kitchen sink and the washing machine will definitely require individual vents. These vents will need to connect to other vents upstairs or can penetrate the roof individually, depending on layout.

The additional vent you mentioned cannot be used as vent for these fixtures unless you are connecting back into it... ;)

Finally, I attached a drawing showing you how to pipe this up if the lavatory is closer to the toilet than it appeared in your drawing. In my drawing I used the lavatory drain/vent to act as a WET VENT for the toilet. The vents need to connect together at 48" off the finish floor and then a 2" vent goes up and connectto a 2" vent in the tatic or can penetrate the roof itself. The kitchen vent goes up individually and connects in attic or goes out the roof 2". This should at least get you thinking about how vents and drain work together.

Post back...

MARK

Nicely drawn and explained Mark ! Wanted to leave positive feedback for you - but got the usual message... Milo

Hi Massplumber

You just about nailed it. The only difference, in my scenario, there is an existing vent right in the middle of your long sweep elbow. The existing pipe is steel which I will disconnect and replace with PVC. The new lavatory will be centered in front of the vent so I was going to put a T facing out and just borrow the hole in the ceiling and redo the vent in PVC. The toilet sits about seven feet from the vent.

Thanks for the drawing!! This really helps a lot. The vents are making more sense now. I can easily add a vent for the shower and I will post another drawing tomorrow. So the sinks need their own vents because they sit higher and the shower and toilet can be "wet vented" if they are close enough to another vent?

So a "dandy cleanout" is a wye at the trap with a plug on the inside of the room?

I have attached another drawing to give a better idea of the layout. I left the kitchen sink off this drawing but it sits about 8 feet to the right of the lavatory. The existing vent in the bathroom penetrates the roof so I'm wondering if I can tie all of the vents together including the kitchen sink and use just one roof penetration or does the kitchen sink require its own? Also, you mentioned the vents tie togther 48" off the floor, they can be higher, right? I would like to run the horizontal pipe through the attic.

Heres the drawing


How about this for a layout? I have modified the pipe runs so the washer connects closer to the toilet. I have already laid the horizontal pipe and stopped at the long sweep elbows. I just want to verify that my venting is correct before I start cutting holes in my roof. I have been reading other posts that say you can vent the entire bathroom group off the lav, however in my case the lav is downstream of everything else but the vent is already there. I would have to cut through the roof for the vent for the washer. The main pipe run is 3" and everything else is 2". Washer and shower will both have 2" traps. I have no problem running these vents I just don't want to create more work for myself than necessary. Thank you.

I am not sure I am using the site properly because I have added to my post but have not gotten a response. FAQ says you should click "edit" to edit your post but I don't see the edit button so I don't know if I posted correctly or not.

The original post is here:
https://www.askmehelpdesk.com/plumbing/rough-diargam-correct-392534.html

The only relavent drawing is the very last one and the only relavent paragraph is also the last one. Can someone please tell me if my drawing is correct?

I am a newbie to posting, thank you.

Hi weekend...

All looks OK, except...

You cannot use a washing machine to wet vent a toilet... simply not allowed anywhere that I know of. Here, the volume and the velocity of the water from a washing machine could siphon the internal trap to the toilet and cause bubbling/gurgling issues and could allow sewer gasses and smells to be an issue for you.

Stick with what you have, but add a toilet vent as well and you should be all set here... see pic. Below.

Let me know if you want to discuss more.

PS: A dandy cleanout is simply a tee fitting with a plug... it is usually installed just as you come out of the floor with the pipe... see image below. The idea here is to allow FULL SIZE DRAIN access to the drain line should it clog up. You can have it so the cleanout sticks into the room or you can hide the cleanout behind the wall and install an ACCESS PANEL to access in the future. Decent access panels are sold at home depot and Lowe's for pretty cheap... ;)

MARK

Sorry... I've been super super busy the last couple weeks and haven't been in much! I saw your post and answerd it back at that post.

Let me know if you have questions...


MARK

Hi Mark,

Thanks a lot for the advice. I can easily add a vent for the toilet and dandy cleanouts as well, this makes perfect sense. This advice is exactly what I needed as I would rather have the job done CORRECT the first time. And besides I did not wait long at all. I just posted my revised drawing the other day. Thanks again for steering a weekend warrier in the right direction.

Derek

Hi Derek:

Me and Milo are both glad to help here... :) Let us know if we can help with the plumbing, electrical or the heating. We have a pretty knowledgeable group here!

Thanks...

MARK