Is it sufficient to have a single 4 inch vent for a bath, a toilet and a sink draining into the sewer line from the main floor of our house to the basement sewer stack and is the placement of the vent important in the plenum (see web page: http://web.mac.com/pughimag2/iWeb/Site/Library.html

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Originally Posted by pughimag

Is it sufficient to have a single 4 inch vent for a bath, a toilet and a sink draining into the sewer line from the main floor of our house to the basement sewer stack and is the placement of the vent important in the plenum (see web page: Library

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Okay...

Let's start with a few questions of my own first.

A) Exactly how are you defining the word "plenum"?

B) What's with the vent 90 below the floor and what is it venting?

C) What's with the Sanitary Tee on it's back with the above mentioned vent 90 coming out of the top of it?

D) What's with the Sanitary Tee on it's side and what is it picking up?

E) What's with the 2" running trap and the dog legged riser coming out of it?

F) Where are you posting from so that we can figure out which code applies to you and then better decide who should help you correct this abortion?

Sorry, but having Plumbed under both the UPC and the IPC codes over the past three decades, that is really the best advice I can give without more information.

First, Thanks for your response.

1) The sloped horizontal run where all the connections come into underneath the floor is what I'm calling a "plenum".

2) Before we connected anything we had the following pipes sticking out of the modular house floor into the basement from the bathroom above: five copper pipes (hot and cold for bath and sink and a cold pipe for the toilet), a 4 inch vent running into the roof, a bath drain connection (no P-trap), a toilet connection, a sink connection and an extra vent for basement plumbing (2 inch) connected in the wall above the basement to the 4 inch vent. The two gray pipes that you see in one of the pictures are just conduits that were installed so that we could send radient heat pipes up to the second floor space for heating purposes. I'm not sure what the "90 below the floor means" in your question, maybe it's what I'm calling a plenum.

What we did was to put a P-trap in the bath connection and join it to the horizontal run (plenum) that we put together just under the floor. We joined the horizontal run to the 4 inch vent, the toilet, the sink and then ran everything down to the sewer, which is the long 4 inch vertical pipe in the picture.

I'm posting from Asheville, NC (28806).

I gather what we have is an abortion? Please tell me more if you have time - thanks!

I should add that in the vertical pipe at the very back of the drain_plenum.jpg is just an independent vertical radon vent coming from under the basement and exiting through the roof :D

I printed out your pictures and studied them with much interest. I saw pretty much what growler asked about but couldn't believe a job could get that far along without sombody yelling, "Hey! Hasn't anybody ever read a plumbing book?" That's when I PM-ed growler just to see if I was off base or mistaken.
With all those twists, turns and doglegs you're setting yourself up for drainage problems. I see a lot of short radius 90's that could have replaced with 45's for a better flow pattern. I don't mean to sound like the voice of doom but was a permit pulled for this and will it be inspected? And the one question that stands out in my mind is who advised you on the layout and installation? I can see entire sections that should be cut out and brought up to code. And your use of the word, "plenum" threw me until I realized that you meant to say,"manifold".
What's going to happen next? Regards, Tom

Thanks guys, it's obvious that we need to start again. First, I want to say that yes, a permit has been pulled but we are doing this as owner/builders with only a book to work with. We did not glue any of this together so it's easy to take apart - it's all dry fitted. We tried to get some advice but it's very difficult to get help in the middle of building season which is why we thought to give it a try. We thought we would dry fit everything and then get some advice.

Should we be taking the sink, bath, toilet to the vertical sewer line individually without using a manifold?

Any guidance would be much appreciated. We'll start work right away. We obviously need to consider flow and use 45 bends instead of 90's for starters. We are really only plumbing a single bathroom so I'm hoping we can recover from this quickly, especially since no glue has been applied yet and Lowe's is only a couple of miles away.

I appreciate the honest comments

I have a great idea. Why not draw up a floor plan, (you should have had a set drawn up anyway for a job this size) along with measurements, fixture placement and existing drainage and vents and let the experts on this page see what they can come up with in the way of a workable plan to follow?
A word of caution when dry fitting PVC fittings. The female hubs have a slight taper to them. If you slide the male end of a pipe in too far it will bind and be difficult to pull apart. But you're going to find that out for yourselves pretty soon. Good luck, Tom

I have a set of plans showing the bathroom layout as well as an isometric drawing for the plumbing. When I get home this evening I will try to attach an image. It's pretty much per the photographs on the web page (before we installed the 3 inch pipes that you see in the photographs). We have a 4 inch pipe coming out of the basement floor (the sewer line). We have the pipes coming from the basement ceiling (bath, vent, sink, toilet). The bathroom config is not going to change so what you see in the pictures is what we have to work with.

Is it a good idea to use a manifold? Where the pipes emerge from the bathroom into the basement is our mechanical room so we don't have to spend a great deal of effor to hide the pipes in there. The vertical pipe into the sewer is going to be in a 2x6 wall.

I'm curious to know why you didn't tie all of this into the 3" stack underneath and behind the shower.

The 3" stack behind the tub's P-trap is the radon vent. As far as I am aware I cannot tap anything into the radon vent.

I have enlarged the portion of our building plan that shows the main floor bathroom and converted it to pdf format and uploaded it to my web site here - http://home.att.net/~pughimag/jpegs/...ipe_layout.pdf - you can see that the dotted line portion of the drain system is not present but the tub, the WC, the LAV drains and a 3" vent and 2" basement vent ( we have a roughed-in bathroom in the basement) that show in the photographs I have posted go through to the basement. We decided to construct the manifold to take everything to the sewer stack which actually lies in the other direction to that indicated on the diagram. This is a modular house that was lifted into position with just the bathroom pipes protruding under the house. The LAV connection is vented in the bathroom wall as indicated in the diagram. What are your recommendations given that what we did is such an abortion? What is wrong with what we did apart from not making the bends flow better using 45 bends rather than 90. Would this remedy (using 45s) make everything else right? Thanks.

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Originally Posted by pughimag

I have enlarged the portion of our building plan that shows the main floor bathroom and converted it to pdf format and uploaded it to my web site here - http://home.att.net/~pughimag/jpegs/...ipe_layout.pdf - you can see that the dotted line portion of the drain system is not present but the tub, the WC, the LAV drains and a 3" vent and 2" basement vent ( we have a roughed-in bathroom in the basement) that show in the photographs I have posted go through to the basement. We decided to construct the manifold to take everything to the sewer stack which actually lies in the other direction to that indicated on the diagram. This is a modular house that was lifted into position with just the bathroom pipes protruding under the house. The LAV connection is vented in the bathroom wall as indicated in the diagram. What are your recommendations given that what we did is such an abortion? What is wrong with what we did apart from not making the bends flow better using 45 bends rather than 90. Would this remedy (using 45s) make everything else right? Thanks.

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Well, you still have sanitary tee's on their back and on their side, for starters.

The running trap on the shower is a definite no-no.

The 3" vent 90 below the floor is going to have to go -- As are the horizontal medium sweep 90's on the lav drain.

Also, if memory serves, your vent is in the wrong location if it was your intention to wet vent the bathroom group.

Sounds like we need to call in a plumber if we can find one who has the time - thanks.:)

I was reading last night that it's best to use long-turn elbows everywhere (space allowing) because of the restrictions on short-turn elbows. iamgrowler - it's informative to know what is wrong so I appreciate the information.

I will start to read everything I can as well as talk to plumbers to see if I can find out how it can be done right.

I have all the space in the world to work in, three pipes to send to a 4" sewer line in the basement floor and a vent line. I still believe that it really should not be very difficult as long as I can find out what the rules are so that I can buy the right elbows and traps and configure them correctly. Thanks for the comments. Glad I asked.

Well, we couldn't find a plumber to help us (or even quote us on the job) to figure out what was right after reading everything that was posted here about what we did wrong so we ordered a couple of books from Amazon and sent an email to the city inspectors to let them know that we would do the plumbing ourselves.

In one weekend we plumbed in everything and had our work inspected and I'm pleased to say it passed first time. Plumbing is really not very difficult, it's just physics. The rules that are inconsistent from state to state and county to county are what cause everyone heartburn. City inspectors can be very helpful when it comes to explaining the rules.

We found that you can do without a plumber in some circumstances (your own home and a new installtion in particular) and save a bundle. Work with the inspectors and you can get it done.