Should I rough-in for a bathroom?

kxmotox247 · Apr 21, 2007

Now seems the time to do it. I'm building a large shop behind my house and have been toying with the idea of roughing in a bathroom. Toilet, sink and corner shower. Right now I have a 3' deep utility trench to the shop. No concrete floor yet. No walls on the shed. The excavators are anxious to close me back up though.
I have looked all over the web trying to find info on how to rough this combo in...dimensions, spacing, pipe size, etc... and haven't found what I need.
I'm down hill from my septic tank so I think I want to just stub up a waste pipe. What else should I stub up? How far below the frost line should the waste line be? I'm thinking that I may just have the 4" pipe leave the building and head in the direction of where I may have to put in a new septic for the house. Any source on the internet where I can see some dimensions for a small bathroom that's going to show me pvc pie layout?
Any help would be appreciated. So far, this site has the most info out there! I thought the garagejournal.com would have had what I needed.
Thanks!

Leejosepho · Apr 22, 2007

kxmotox247 said:
... building a large shop behind my house ... roughing in a bathroom. Toilet, sink and corner shower.

Toilets are self-venting, but the waste line must be vented so the toilet discharge does not affect the shower and sink traps. So, maybe you could bring the waste line into the corner of the building, turn it up, then T-branch low along one wall to go over and catch the toilet, then turn along the other wall to get the sink and shower drains, followed by a vent up through the roof.

kxmotox247 said:
Right now I have a 3' deep utility trench to the shop ...
I'm down hill from my septic tank ...
How far below the frost line should the waste line be?

If you cannot gravity-drain to a septic system, then you are going to have to pump ... and that sump could be set either inside or outside below the frost line with a 2â€ discharge line sent to your septic tank. Overall, and if possible and permissible, it might be better to install a small tank and drain field just for the shop. And as I understand things, at least short waste lines going to septic tanks do not have to be below frost lines. But, a sump discharge would be a different matter.

kxmotox247 said:
I'm thinking that I may just have the 4" pipe leave the building and head in the direction of where I may have to put in a new septic for the house.

If that would be downhill, that could be great.

Sponsor · 2022-01-29T12:20:58-0800

Master Plumber Mark · Apr 22, 2007

how far downhill???

Its always best to do the work before the
concrete is poured.....

if you can figure out where you want the bathroom you
can make life much easier now than later..

running a 4 inch pvc pipe to the toilet and branching off for the shower and sinks is pretty easy....

your big problem is the fall to the sewer,,, that will be
costly...and a general on-going pain

depending on where you are in the country,,

,how deeep do you have to trench for your pressurized uphill sewer line to the septic is the big issue..??...

how far below the septic is the garage going to be??

heres an idea that might sound stupid but....
..
I would almost consider the cost of raising the building up a row or or two of concrete blocks
if it would give me fall to the septic before I would put a sewage pit into a barn
and then pipe it up hill to the septic,, thats a problem you need to avoid.

have fun

kxmotox247 · Apr 22, 2007

Thanks guys. The building is already being raised help match the elevation of the house. 17 truckloads of clay later and it's getting close.
They're going to stand the building shell up and then come back to pour the concrete floor inside.
Right now I only have to decide what pipe to put in the trench and what kind of elbow to turn it up into the building.
Obviously, I need to consider a vent pipe and where that is going to hook in.
Are there any pictures or diagrams that show a typical bathroom rough-in?
Thanks,
Josh

FloridaOrange · Apr 22, 2007

kxmotox247 said:
Are there any pictures or diagrams that show a typical bathroom rough-in?
Thanks,
Josh

This is the only layout I have in cad with a corner shower. Maybe this will help you get started on how you want your layout to look like.

hj · Apr 22, 2007

drains

The part of the system you have to install now is the most important in the long run, and also the easiest to "screw up" during the installation. Before you can install the piping, you have to also know how the pipes above the floor will be arranged. I don't know of any drawing that I would trust to show you how to put the piping in properly.

Leejosepho · Apr 22, 2007

With the sink and door locations switched, that drawing FO put up is exactly what I had envisioned here ... and one thing you might consider is to bring your waste line in through the foundation about halfway between the locations for the toilet flange and shower drain, then leave 2' of the floor unpoured along each of the two outside walls until after the plumbing has been installed.

Kordts · Apr 22, 2007

leejosepho said:
Toilets are self-venting, but the waste line must be vented so the toilet discharge does not affect the shower and sink traps. So, maybe you could bring the waste line into the corner of the building, turn it up, then T-branch low along one wall to go over and catch the toilet, then turn along the other wall to get the sink and shower drains, followed by a vent up through the roof.

Since when did toilets become self venting? On a slab, I will wetvent the toilet and shower thru the lav.

Leejosepho · Apr 23, 2007

kordts said:
leejosepho said:

Since when did toilets become self venting? On a slab, I will wetvent the toilet and shower thru the lav.

Click to expand...

I am no expert plumber, and I do not mean to say toilets never need vents. I read "toilets are self-venting" from somewhere here on these boards, and I do know that in at least some situations or configurations a toilet can dump into an unvented line and still work just fine.

In this particular case, I was thinking of a toilet along one wall and less than 5' from the exiting waste line near the corner of the room, and I am assuming the vent would then best be at the end of the run along the adjoining wall and after the sink and shower drains to keep toilet flushes from affecting those traps ... exactly as you have also described, I believe. My point, then, was simply that the short line from the toilet to the outgoing waste line did not also need to be vented behind/beyond the toilet.

But, I could be quite wrong.

kxmotox247 · Apr 24, 2007

Thanks for all the info guys. I laid a 4" diameter pipe in my utility trench last night. Once the building is up but before the concrete floor is poured, I will locate the drains and vents. Can I put in a shared drain between the sink and shower?
What size vent pipe is required? 2" or 3" What size should the vent pipe be to the roof?

Thanks again!

Geniescience · Apr 24, 2007

kxmotox247 said:
...I will locate the drains and vents. Can I put in a shared drain between the sink and shower?
What size vent pipe is required? 2" or 3" What size should the vent pipe be to the roof?

Post a diagram. Now is the time. As you have read above, plumbing can be seriously difficult to understand, at this stage. One little thing misunderstood... and you are in for trouble.

No more written descriptions. Please. Draw and post.

david

hj · May 21, 2007

drains

It is even worse that you didn't use the proper fittings for your connections. But like many DIY projects, once the concrete is poured no one will know the difference, at least until you have a problem and it becomes difficult to solve it.

Terry · May 21, 2007

Maybe I can draw a picture and scan it in later.
It's just hard to start from scratch on this stuff.
Most plumbers aren't allowed to even touch the waste and vents for the first year.
Reminds me of this weekend at the University Street Fair where my son's band was playing.
A blind man came up, bumping into things, and asked my youngest for directions.
My fourteen YO told him,

"It's over there!"

The blind guy hit him on the arm, and said

"Never tell a blind man, it's over there!"

I will say the plumbing looks a bit like my fathers pole barn plumbing on the ranch. It was hard telling him, (I was fairly new at plumbing at the time) that it looked strange to me. He had a doctor of law, but I had been in the trenches.
Let me see what I can come up with.

kxmotox247 · May 21, 2007

Thanks Terry! Any help would be appreciated since I still don't have concrete down yet and it would be really easy to access the pipes.

My father taught me lots of things. Everything but plumbing! Ha!

I had a guy who supposedly knew plumbing look at my basic plan on paper and even the fittings and pipe in my truck. He thought it looked okay. Maybe he was just being nice and didn't have the heart to tell me I was going to have problems.

Seems like maybe I need another vent for the shower drain which is on the far right.

Jadnashua · May 21, 2007

You should be using Y's to direct the water where you want it rather than the straight T's. Waste fittings have an angle or curve in them to direct the waste in the right direction.

Geniescience · May 21, 2007

kxmotox247 said:
...I don't recall using any straight T's. .... showing my WYE's. ....

All wrong.

If you tell me you are willing to cut out all the fittings and throw them away, you'll get my support. Read both of hj's comments above. He is fair and he is saying things that help even though they hurt too.

Search and read up on "long sweep" and "combo" and "sanTee" or "sanitary tee". You need to know the difference. You can ask Google to give you definitions by typing the word define: before the actual term you want defined.

That is all for now. More later.

david

edit: the problems will come later when blockages happen. After some solids have been flushed and not evacuated all the way, they will dry there and stick. Each of the bad connections is a slow-me-down point, not a speedy turn for water to carry its load through the corner.

Leejosepho · May 21, 2007

I am not a professional plumber, but all of my plumbings work ... and I say one modification will leave yours working fine. The flow from your shower is not going to siphon its own trap dry, and neither will it siphon a vented sink trap. A toilet is essentially "self-venting", and the downstream vent you have in the line will complement that fact.

The only major change I see needed is to cut and cap the line you have intended for the sink drain and to instead drain the sink into a sanitary Tee in its vent pipe. Also, a long-turn ell might be better at the bottom of that pipe.

FloridaOrange · May 21, 2007

As mentioned before, you need long sweep wye's in there. If you can wet vent and remain code compliant you can simplify your layout a bit. Check this pdf sketch.

Geniescience · May 21, 2007

just in case you need more reassurance, and clarity: so far four people have said you used the wrong fittings: you need Wye's and long sweeps. On the other hand, everything you labelled as a Wye above in the picture, is not a Wye. Just so you know, what is Wye isn't. That alone is astounding. And bad. And doesn't predict a happy future for the rest of this project. All the objects you called Wye are actually SanTee. To you they may look Wye-ish. They are San Tee's . Then, to help confuse you more, one guy steps in here and says golly Sarge I see a problem, but he doesn't point out the big one. That said, you better prepare yourself for a few more interesting bits of learning, as your design has even more problems, and like many would say, it may be better to just let him make all his mistakes and sstop trying to help, as it isn't making any improvement. Yet.

David

Geniescience · May 23, 2007

progress again

it's been a few days and you've made some progress, after a few private messages and internet searching. The photo has been relabelled, but uh-oh it still shows a tight radius turn labelled as a long sweep - also not right. So far, you've found out that Wye's are essential. Venting is the next big subject. Unfortunately it is difficult to understand until you've had time to think it through several times. It's like a mental paradox with trick questions that appear simple. ".... The flow from your shower is not going to siphon its own trap dry ...." is not true in the drain layout proposed in that post. Sorry to tell you that. Hope you get the help you need to add venting in all the right places.

If I were in your shoes and if I felt forced into glueing something together without consulting anyone first, I'd send that P-trapped drain (on the left) to that vent (in the middle of the photo) first, and then direct it over to the big common drain, where I'd connect with a Wye, downstream below the big vent you have on the far right hand side of the photo. The sink drain would not go towards that drain or vent as now shown, but instead get directed towards the main drain (in that direction), and connect into the shower drain pipe using a Wye, just before the shower drain connection described in the preceding sentence. (Yes, the sink drain is a vent with a SanTee in it above the floor waiting to receive the sink connection). Also, I'd use 3" pipe for toilet waste. I'd still have to know more about what you are planning at each fixture and vent, too, before building it like that. But this isn't a recommendation for you to build it this way right now, for several reasons. In the real world, I would consult too; and, I'd know more before starting.

david

Should I rough-in for a bathroom?

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