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jkg81 10-02-2013 01:59 PM

Drain and Vent Layout Help
 
I was just looking for a little help with a plumbing layout for a bathroom.

This room was an addition to the house. The light brown area is dirt floor and I'm hoping to make as many connections there as possible. The darker brown area is concrete slab. The red lines are the drain lines, with the main line from the toilet being 4" and the rest being 2", except for the 1st sink, which was 1 1/2" (2x4 exterior wall). I was also going to run 2" vents everywhere, connect them in the attic and run 1 roof penetration (not sure about the size).

The double sinks on the exterior wall concern me because of the 2x4 studs that the drain pipe will have to pass through to get to the 2nd sink. Was considering using AAVs here to minimize further cuts to the top plate and working in a low attic. Also considered tying the sinks in directly to the sewer line (black horizontal line) but the old sewer pipe is concrete and, although it's in good shape, I'd like to mess with it as little as possible. Was also curious if I could run the sink drain outside underground and make the connection there (the Blue Line).

My other concern is that I want to minimize roof penetrations. There's already a 2" vent in the attic from an old drain that I was curious about tapping into. I would like to tie all my vents together in the attic and use that vent or enlarge it somewhat.


Just wanted to get thoughts on whether this would generally work for a drain and vent layout or if there's an easier way. I would like to connect to the sewer outside the house to minimize slab cutting and also to make it easy to service the connection to the concrete sewer pipe if anything ever happened.

I'm aware that the shower needs to be vented within 5' and the first sink must be less than 42" from the other for venting (but I'm not certain how to share vents between fixtures or if there's a layout that would make this easier). Please pardon my lack of knowledge - I really appreciate the help. Feel free to ask any questions and I'll respond ASAP. Thanks

http://i1011.photobucket.com/albums/...ps66ca4d8f.jpg

Ghostmaker 10-02-2013 07:09 PM

What state do you live in? What you drew is not legal under the IPC. It also would help if we knew where that 4 inch leaves the area.

TheEplumber 10-02-2013 07:48 PM

Per UPC it's true that a 2" trap arm max. length = 5ft and 1.5" = 3.5 ft. but your toilet is a 2" vent and branch line-

For the lavs- I'd put a fixture cross between the 2 and pipe to the exterior. Both can be served by a 1.5" common vent.

Also, how are you running to the tub? The tub's trap is under the floor-

Curious as to how you got to keep the concrete pipe under the floor

jkg81 10-02-2013 07:49 PM

Thanks for the reply.

Forgot to include, but the state is Texas. The city I'm in uses the 2006 UPC and allows AAVs.

Not sure which 4 inch you're referring to, but the 4" (main drain) red line at the top isn't installed - I guess it would just end in a cleanout or maybe transition to the green vent. The other end wouldn't go directly to the toilet like that (no sharp angle) but would bend to connect outside and the toilet would come in via a wye I guess.

The black line (sewer) is also 4" but continues until it hits the city connect.

jkg81 10-02-2013 07:55 PM

Quote:

Originally Posted by TheEplumber (Post 1248885)
Per UPC it's true that a 2" trap arm max. length = 5ft and 1.5" = 3.5 ft. but your toilet is a 2" vent and branch line-

For the lavs- I'd put a fixture cross between the 2 and pipe to the exterior. Both can be served by a 1.5" common vent.

Also, how are you running to the tub? The tub's trap is under the floor-

Curious as to how you got to keep the concrete pipe under the floor

Ok thanks, so the sink drain would be between the 2, drop through the slab and connect outside with a 1.5" vent.

The tub and washer drawing is a little confusing. I was going to use a 2" line from the tub, include a p-trap, and have it meet the 4" red drain. The vent would tie into the washer vent above the overflow line.

jkg81 10-02-2013 07:57 PM

Maybe it would look a little more like this.

http://i1011.photobucket.com/albums/...ps6b8d96ae.jpg

TheEplumber 10-02-2013 08:07 PM

A lav is 1 fixture unit and a horizontal 1.5" pipe is allowed 1 FU. So the line to the lavs must be 2". Center it between the lavs and use a 2x1.5x1.5x1.5 fixture cross (google it) 2 lavs can vent with a common 1.5"

Add a clean out behind the washer.

The 2" branch serving tub, shower, etc needs to be downstream of the toilet vent.

side note- fur out the 2x4 lav wall to 2x6 or use structural plates on horizontal pipe holes

jkg81 10-02-2013 08:22 PM

Thanks Eplumber. Makes sense.

Two more questions, I'm not sure how to vent the toilet so that the line from the tub/shower/washer is downstream but still inside the structure. Can the toilet vent run horizontal to the left until it gets to the (3'4") wall behind the toilet and then go up?

You said I can wet vent the tub on top of the washer, but can I do it the opposite? With the tub tying in directly to the vent and the washer draining above that, or does the volume of water from the washer prevent that?

jkg81 10-02-2013 08:26 PM

As to your question about the concrete sewer pipe - I guess it's original to the house in the 40s but looks in decent shape. Sometime in the 60s they poured a slab over it without replacing it.

TheEplumber 10-02-2013 08:43 PM

Quote:

Originally Posted by jkg81 (Post 1248900)
Thanks Eplumber. Makes sense.

Two more questions, I'm not sure how to vent the toilet so that the line from the tub/shower/washer is downstream but still inside the structure. Can the toilet vent run horizontal to the left until it gets to the (3'4") wall behind the toilet and then go up?

You said I can wet vent the tub on top of the washer, but can I do it the opposite? With the tub tying in directly to the vent and the washer draining above that, or does the volume of water from the washer prevent that?

Generally speaking- no on the toilet vent. However, our inspectors have always allowed it if the vent is graded and comes off above the drains center line and you must use a 3x2 y for the vent connection.
Bottom line is to check with your inspector first.

Another way- and the preferred way- run the 3" line to come up in the wall behind the toilet or the far wall. Turn up a 90, stack a santee on it pointing to the flange location- this will become the toilet branch. Bush the top of the santee down to 2" for your vent. This will require about 15" of depth

Disregard what I said about the wet vent. In my head I had the tees above the floor- it's been a long day... and no- you can't put the washer above the tub- sorry

jkg81 10-03-2013 09:17 AM

Ahhh ok that makes a lot more sense - I didn't think of running the toilet drain that way. Shouldn't be any more difficult but I am concerned about the depth. I'm not sure I have 15" of depth below the slab without running into slope issues to my sewer line. The sewer like runs just under the slab's footing so it might not be much more than 12" at that spot.

Would the lavatory drain just run straight down thru the slab, take a 90 turn and run underground to the sewer tap?

Javiles 10-03-2013 11:53 AM

Quote:

Originally Posted by Ghostmaker (Post 1248870)
What state do you live in? What you drew is not legal under the IPC. It also would help if we knew where that 4 inch leaves the area.


Not sure it will fly under the upc ether, recommend you put that washer on its own branch, get some one to redraw the set up simplify it down

jkg81 10-03-2013 01:47 PM

Thanks! I redrew it to take eplumber's suggestions about the toilet and the lavatories into account. I'm sure there's a way to simplify the shower, washer, and tub layout, but I'm not sure how. Any ideas?






http://i1011.photobucket.com/albums/...ps08b0739a.jpg

Ghostmaker 10-03-2013 07:21 PM

It's important that we know what state you reside in. What may pass under one code may not pass with another.

TheEplumber 10-03-2013 07:27 PM

Quote:

Originally Posted by Ghostmaker (Post 1249181)
It's important that we know what state you reside in. What may pass under one code may not pass with another.

lol- he answered that in #4 as well as stating UPC


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