Basement Plumbing Layout Review

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by jpb123, Jan 24, 2012.

  1. jpb123

    jpb123 New Member

    Messages:
    15
    Location:
    Iowa
    Could someone please review the attached sketch of how I would like to plumb my basement bathroom? The only existing lines in the drawing is the 4" building drain that runs from the exterior wall of my home to a tee where a 3" drain runs toward a 3" stack that feeds an upstairs bathroom and a line that I believe is 3" that serves the kitchen upstairs and a floor drain that was removed.

    I would like to tie into the 3" line below the floor and put in a double wye, one side for a floor drain and the other side serving the rest of the bathroom group. The 3" will run all the way to a toilet and will have a wye that runs to 2" to serve the shower and bathtub. A 2" vent (maybe this could be 1 1/2" now that I look at it) will serve a sink. On the other side of the room, I plan to remove an existing floor floor drain to to connect to the existing wye that is already in the 4" main service line and install a new 3" floor drain (that will be near the laundry machine and utility sink in case the hoses fail at any time) and a 2" vent that will serve as the drain for the washing machine and the utility sink. This will be vented with a 2" lihne that will connect back with the shower vent and the sink vent into an AAV near a point where I can run the vent through the upstairs wall in a future project.

    Please look at my drawing and give me any comments or suggestions. My particular concern is using the vent as a drain line for the washing machine and the utility sink. Could anyone give me a recommendation as to whether I need to use a studor "maxi vent" rather than a "mini vent"? The sizing information on the specification sheet was confusing to me in that it had maximum dfus for branch and maximum dfus for stack.

    Thanks for your help.

    BPP2.jpg
  2. Terry

    Terry Administrator Staff Member

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    15,280
    Location:
    Bothell, Washington
  3. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,259
    Location:
    Land of Cheese
    Generally speaking, every trap must have it's own vent. There are almost no homes that cannot have a vent run from the basement through the roof, and it's always best to avoid using an AAV.

    Using 2 seperate wyes in the line would allow for a floor drain and the bath connection to be made properly. I would always be concerned that any sewer backup would start with sewage coming back into the house through that floor drain.

    The other thing we cannot see is how deep the existing building drain is, which is important as that would determine where the connection has to be made. If it is not deep enough, the added drains would not be allowed ample pitch to the connection.
  4. jpb123

    jpb123 New Member

    Messages:
    15
    Location:
    Iowa
    Thanks Terry. That was a nice link. Very informative. I just realized that I had the shower drain connected to the tub drain before the vent/sink drain. I assume that I need to have the toilet, floor drain, and bathtub drain connect individually to the 3 inch drain line, correct? Could you or anyone else reading this thread give me some recommendations on how to improve this?
  5. jpb123

    jpb123 New Member

    Messages:
    15
    Location:
    Iowa
    Thanks Cacher_chick. I don't know how deep the floor drains are or how deep the main service line is but there is a floor drain already in place at the point where I want to put the new floor drain/washing machine/utility sink. Is there an opinion from the plumbing community on using the check valve floor drains (not sure the proper name) that only allow flow to exit the drain? Would you advocate that I not put a floor drain over near the washing machine (the only reason I was thinking about putting one in was because I;ve read on this forum about recommending that one be installed incase there was a line or machine failure).

    Am I correct in understanding that If i vented the shower within appropriate distance and connected the shower discharge past the tub vent/lav drain and then into the toilet drain line, that it would be considered appropriate?

    At this point, I am set on using an AAV since I don't want to run the vent all the way up to my attic. I understand that running a new vent up to the attic and out the roof would be an ideal situation; however, I am trying to vent everything with one AAV at this time with the AAV location being in a place where I could run the line to the attic in the future if I choose. I would appreciate some plumbing expertise on the AAV and which one I need since it is beyond my expertise.

    Thanks for your help.
    Last edited: Jan 24, 2012
  6. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,259
    Location:
    Land of Cheese
    As drawn, the tub will need it's own vent added. Without seeing an new drawing, I'd rather not guess at what you are asking in regards to a wet vent.

    A sink drain other than a lavatory must be 2". Here we are allowed to connect the sink over the washer on the vertical. Your inspector may require a re-vent on the sink. The laundry/sink must connect to the main line, not the floor drain line.

    Cleanouts under the sinks.

    In some places, trap primers are required on the floor drains. I have no knowledge of a dependable floor drain that would not allow backup.

    Putting in the drains will be 10 times more work than running a proper vent. :rolleyes:
  7. Hackney plumbing

    Hackney plumbing Homeowner

    Messages:
    1,174
    Location:
    Alabama
    In a residential setting I've seen more floor drains flood houses from a backed up drain than I've seen a floor drain save from flooding. 1/2 of them the floor is no sloped properl and the water runs the wrong way.LOL
  8. jpb123

    jpb123 New Member

    Messages:
    15
    Location:
    Iowa
    Ok, no floor drain near the washer it is :D. The other floor drain will be for furnace condensate and for the water heater pressure relief in case it is ever needed so I think it's a necessity.

    I appreciate your help and I'll update my drawing tomorrow to better explain my questions.
  9. jpb123

    jpb123 New Member

    Messages:
    15
    Location:
    Iowa
    Ok, here is the updated drawing. Are the changes I made acceptable? They are:

    -Connected the sink drain to the bathtub trap arm to use as a vent before the bathtub trap arm connects to the shower drain. Then have both drains connect to the toilet drain line before making one connection for them all in the existing 3" drain line.
    -Connect the floor drain and bathroom group in their own individual 3" combination y-1/8 bends
    -have the utility sink discharge above the washing machine and remove the floor drain near the washing machine

    How about the venting? Can I vent the washing machine and utility sink with a 1.5" instead of 2"?

    BPP3.jpg Could someone comment on the vent sizes and what size aav I need?
  10. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,259
    Location:
    Land of Cheese
    1.5" vents would be fine. Sink drains need to stay 2"

    I can't help but wonder why you are not piping the bath to the main line near the laundry?
    In any case, most would run in whatever direction means less breaking and digging.

    You should get your plan approved by the local plumbing inspector, as he will know if there are any local code issues.
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