Bathroom Basement Remodel Plumbing Rough-In.

[mjaenke]

Hi, my name is Matt. I've browsed this forum from time to time and have found some very good advice. I've fixed, replaced, renovated other plumbing in my house and now its time for the basement bathroom. So far I've removed all of the old cast iron/galvanized plumbing that was set in the old concrete raised floor. I also cut out 10' of the main cast iron drain pipe and replaced it with PVC. Now I need to start thinking about the plumbing rough-in's before i pour a new floor.

The existing basement floor was blocked out under the old bathroom footprint. I'm not sure why because none of the old plumbing actually went below the existing floor level. I do not know why the builder chose to run the plumbing above the slab at this location. The basement floor drain (not shown in the picture) is buried below the slab and connects to the sewer line in the back yard. Either way I'm stuck with what I've got and that means another raised floor. I'll be building it out of wood though.

Pictured below is:

Cast iron pipe: 4" main drain to city sewer.
PVC Pipe: 4" main drain 10' PVC section. 10' further down is the main stack with main vent (not visible in picture).
PVC Fittings: Proposed locations of drains for new fixtures.
Blue Lines: Drain piping - 3" for Toilet, 2" for Shower, 1.5" for Pedestal Sink
Green Lines: Option 1 - Vent lines running horizontal then up in walls and eventually joining. There is an existing 1.5" vent for the bathroom but obviously that's not up to code anymore. Most likely I'll use an AAV on the wall above the main drain line.
Red Line: Option 2 - Single vent on main drain going to new AAV.



What do I have right? What do I have wrong? I'm not a professional plumber but I do realize the importance of proper draining and venting so criticism is welcome! Any advice to help me out with this project will be much appreciated. Thanks for taking the time to read.

[hj]

About the only thing you have right is the 4x3 "Y" in the main line. You cannot use a sanitary tee for the tub/shower. You cannot run the vents horizontal under the floor, and that "red" vent would have absolutely NO purpose or effect. How I, or any other plumber, would install the piping depends on a lot of factors none of which we know, such as where are the walls going to be located. If they could NOT connect a bathroom to the sewer line without running it above the floor, HOW could a floor drain be connected to it and work?

[mjaenke]

Thanks for the reply. Assume that the concrete wall with the main drain in front of it is North. The inside of the East wall will be located 12" from the center of the toilet rough-in. The inside of the West wall will be 6" from the West concrete wall (West concrete wall not visible - assume inside of West wall is edge of picture). The inside of the north wall will be 6" from the concrete wall. The inside of the South wall is farther out than the picture view shows... in other words the entry door will be next to the pedestal sink, then the South wall.

I will do my best to explain the sewer setup for this house. From a camera inspection of the sewer lines i know the following. The house used to have a septic tank in the back yard (West). Later, when the city installed a sewer line at the street (East), they abandoned the septic tank, turned the pluming in the backyard 90 degrees, ran it South till they got to the South edge of the house, turned the plumbing East and ran it along the South side of the house to the Street. Most of this old clay piping clogged and was replaced with PVC (I have 3 PVC cleanout's in the yard). Now hopefully that made enough sense for me to explain how the floor drain works. The floor drain is 20' farther South (and runs parallel in the South direction to the main drain) than the main sewer pipe shown in the picture. Due to the slope on the main drain, it becomes low enough for the floor drain by the time it connects in the back yard.

Now some questions about your comments. Please show me what T i can use for the shower drain. Is the sink draining into the toilet pipe an OK setup as shown? The vents would run horizontal then vertical once they get to the walls. How else would you vent this? I was thinking the "Red" vent but if it would be useless then I'm stuck.

Thanks again for your time!

[hj]

You cannot use ANY "T", it will either be a "Y" or a "combination Y-1/8 bend" fitting. The vents CANNOT go "horizontal then vertical". They either go vertical or vertical THEN horizontal. HOW I would do it depends on the factors I mentioned earlier. You are trying to get a crash course in drain and vent designs, which can take a long time to learn how to do it correctly.

[cacher_chick]

The main things to remember are-

Each trap must have a vent.
Each vent must be downstream of it's trap.
Each vent must rise vertically at least 44" before being run horizontal.
Drains and vents running horizontally must be pitched.

When you are doing all the work, it can be easier to plan the walls around the plumbing instead of vice-versa.
A plumber must be more skilled, because he never gets that option.

[LHO]

Each vent must rise vertically at least 44" before being run horizontal.

I thought it was 6" above the fixture served by the vent.

[cacher_chick]

I thought it was 6" above the fixture served by the vent.

If the vents are being tied together, the rule is 6" above the flood rim of the HIGHEST fixture, which is normally the lavatory.
44" or greater puts the horizontal at least 6" above any of the common lavatory installs.

[hj]

In order to give a rule which would NOT be ambiguous, it was written 6" above the rim of the fixture OR 42" above the floor, whichever is HIGHER. The reason it was written that way is that you could have a toilet, for example which is 15" above the floor, but then later connect a kitchen sink to it which is 36" above the floor. And if the sink is MORE than 36" because it is being used by basketball players, that is the reaon for the "whichever is higher" specification.

[mjaenke]

I will be using a Y-1/8 for the shower as hj suggested. The shower is a 2" drain which allows me to run 3'6" from trap to vent(i'm only 2'6" or so away from the main line). Could i put a vent on the main line directly ahead of the Y-1/8 for the shower drain connection and be OK venting wise? The sink drain is 1.5" which allows me 2'6" from trap to vent. Can i run the sink drain East till i reach the East wall, 90 North and run under the East wall to the drain (install the vent line vertical up through the east wall)? As for the toilet, can i put in a vent line similar in location to the "red" vent as shown above? These are my current ideas, please include your ideas as well. Thanks!

[mjaenke]

Does a lack of responses to my questions mean that i'm on the right track or that you don't want to provide any advice? Just curious because i'm not familiar with the ammount of reply activity on this forum. Thanks!

[hj]

UNLESS the vent is connected to the 2" drain from the shower, it is NOT a vent for the shower. The same applies for the "red line" being used as the toilet vent. The only thing the "red line" is good for is wasting pipe and time, it has absolutely NO function. I cannot follow your sink drain routing to tell whether it is correct or not, but using 1 1/2" for the sink drain will be a very UNWISE decision.

[cacher_chick]

It is easy to help someone when they have a good understanding of how things are supposed to be and why.
It would take a great amount of time and effort to teach you how to properly install the DVW in a bathroom. It is not because we don't want to be helpful, but because you are asking to be taught something that is not easily done in a web forum.