Plumbing waste lines in concrete slab

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Old 07-10-16, 05:53 AM
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Plumbing waste lines in concrete slab

I’m in the process of building a 40 x 60 pole barn. The building is up and now it’s time to pour the concrete slab. Before I put the stone in and Stego vapor barrier, I need to dig in the plumbing waste lines. I’ve located the primary vent and waste stack which will be 3” and extend from ground to roof. So I feel good about that. I’m a little concerned with the shower, getting the 1.5” pipe in the exact spot. I’ve seen where guys actually build a 1 foot square form with 2 x 6 to leave themselves some “wiggle” room. Is this a common practice or is there another way to accomplish exact pipe location. Also, I’m wondering the best way to drain the sinks. I can only assume “S” traps where pipe goes into floor is best (just seems to make sense to send water down opposed to horizontal), as opposed to “P” trap where pipe enters wall. Is my assumption correct? If so, do I plan for pipe to come up in center of cabinet, or do I offset to allow for trap?
 
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Old 07-10-16, 06:46 AM
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#1, You have gone through zoning, heath dept, and building dept and have a permit for this right?
Adding the outbuilding is one thing but adding a full bathroom involves more permits.
#2, Showers need a 2" drain not 1-1/2".
#3, Yes to the box, it's to make room for the trap needed under the shower.
#4, In most areas S traps are against code because of the lack of a vent to prevent the trap from being sucked dry when water runs down the drain.
Some areas allow you to use an AAV for a sink vent.
Air Admittance Valves (AAVs ) & Air Admittance Vents
I'm sure the real plumbers will pipe in later about the needed vent sizing.
 
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Old 07-10-16, 07:58 AM
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Sink drains usually pop up within the joist bays of the (future) walls. The pipes then will tee-off to the sink at about 16" off the floor, and continue vertically to the roof vents. As Joe mentioned, S-traps are no longer allowed, and while AAVs may be allowed, an atmospheric (roof) vent is definitely preferred.

Do you have a drawing or sketch we can review for you?
 
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Old 07-12-16, 04:05 PM
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Thanks guys...I do a plan but can't seem to upload the file. Just spins, not sure what I'm doing wrong. Any ideas?
 
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Old 07-14-16, 06:48 AM
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Can anyone help me with loading a file? It's and excel spreadsheet that I drew a plan on but can't attach? It's only 450KB so size shouldn't be an issue. I tried converting to PDF and that didn't work. I'm using explorer not chrome...
 
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Old 07-14-16, 07:24 AM
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WIGGLE rooms is essential, Make it good enough in size to swing A p-trap for correct positioning 1.5" piping should be plastic... nothing else.S-traps are illegal in some states {mich} for one. I am a "licensed journeyman plumber' good luck not a big deal.... if this helps, bob s
 
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Old 07-14-16, 05:59 PM
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Can anyone help me with loading a file? It's and excel spreadsheet that I drew a plan on but can't attach? It's only 450KB so size shouldn't be an issue. I tried converting to PDF and that didn't work. I'm using explorer not chrome...
 
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Old 07-18-16, 04:33 PM
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Okay, still can't load plans, so I'll ask my questions. Thanks for the responses so far...

1. Yes, the 2" vs 1.5 " for shower was my bad. I need 2" for shower, got it..
2. Yes, now under "S" trap is the way to go.
3. I was planning a 3" stack for two toilets which are stacked on top of each other - 1st and 2nd floor. Stack will go to attack and out through rook while the other end will meet a 4" sewer line going to septic system. Does this seem reasonable? I vent most of fixtures off the primary as everything is very close (i.e. showers and bathroom sinks). Is it common to go from 3 to 4 inch, any issue doing so. I'm think 4" would be overkill and hard to "hide" in 2x4 wall.
4. Other sinks will vent on their own and meet the primary in the attic. They will be 1.5" drains and I was planning to just vent with 1.5". Does that make sense?

This is a hunting camp that will have limited use, but want to do right...
 
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Old 07-19-16, 08:38 PM
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3. I was planning a 3" stack for two toilets which are stacked on top of each other - 1st and 2nd floor. Stack will go to attack and out through rook while the other end will meet a 4" sewer line going to septic system.
No problem with a 3" stack. A 4" stack is rarely needed. Though a 3" pipe is still difficult to fit into a 2x4 wall. Much easier to upgrade to 2x6 if you can.

The 1st floor toilet can't wet vent up through the 2nd floor bath - it needs its own vent. Code doesn't allow a wet vent across floors. This is usually done through the sink drain/vent, but would then need to be upgraded to 2" pipe. Or might be able to vent via the shower vent. Again, all depends on your layout.

4. Other sinks will vent on their own and meet the primary in the attic. They will be 1.5" drains and I was planning to just vent with 1.5". Does that make sense?
This part sounds fine.

You can try taking a screenshot of your excel plans and uploading them here. This site only allows image file uploads (jpg, png, etc), so that may be your issue. Take a look at How to Upload Pictures.
 
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Old 07-27-16, 11:22 AM
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Deercamp, I moved your most recent post to the concrete forum, you'll get more responses there than here in plumbing.

http://www.doityourself.com/forum/br...-concrete.html

Feel free to keep going in this thread, but since I couldn't answer any of your questions, I figured you'll do better there

-Mike
 
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Old 08-01-16, 07:33 AM
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Thanks Mike!

Another plumbing question...

I plan to polish the concrete floor and use as my finished floor. How do I place the toilet flange? Do I embed in concrete or leave it a bit above the concrete surface?
 
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Old 08-01-16, 11:33 AM
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Leave the 3" pipe sticking 12-18" above the floor capped. Pour the cement and polish it. After all that is done, cut the pipe to floor level with a sawzall or similar, then install a toilet flange that cements to the interior of the pipe. Tapcon to floor.

If you try to install the flange first, it's going to be filled with concrete and torn up from the polishing I'm sure. Plus, you'll have to be really accurate on the height. Much easier to do once the floor is finished.
 
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Old 08-01-16, 11:45 AM
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Thanks for feedback! Make sense...
 
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