How to install vent stack in existing bathroom

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by artistsnature, Oct 31, 2008.

  1. artistsnature

    artistsnature New Member

    Messages:
    14
    After all of the wonderful advice I have received here, I'm pretty sure that the basement bathroom is not vented at all. Neither is the top-most bathroom. I can cut open the walls in the basement and upstairs bathroom to vent the lavatories, but how do I vent the existing shower in the basement? Do I have to remove the pan and run pipe from the shower p-trap? Can I run one long pipe up the inside wall to vent both bathrooms out the roof? Do I have to tie the new vent into the existing vent for the main floor bath? Any advice would be greatly appreciated!
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,684
    Location:
    Cave Creek, Arizona
    vent

    There is absolutely no way we can tell you without actually seeing how the piping is installed. We cannot even be sure they are not properly vented already.
  3. artistsnature

    artistsnature New Member

    Messages:
    14
    Good point. Could someone show me a picture of a properly vented basement shower? At least I would know what to look for...
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,684
    Location:
    Cave Creek, Arizona
    vent

    Unfortunately there are many ways it could be properly vented, so a better way would be for you to give us a picture, or drawing, of your drain system. Even this might not help because there could be a vent that you overlook because it is not where you think it should be.
  5. artistsnature

    artistsnature New Member

    Messages:
    14

    Ok, let's see if this schematic uploads correctly. The soil stack is just outside the shower; there's no clean-out; the only pipe leading to it is the 2" horizontal pvc that drains the washer and lavatory in the basement, and the dishwasher/sink and upstairs shower (they each have pvc pipes running directly into the horizontal waste pipe). The vent stack is directly above the soil stack, and is 1.5". I cannot see any other indication of a vent pipe, and I'm about ready to rip the walls down to see if at least the lavatories are vented. If the basement shower is vented, it is under the concrete floor. I ran a hose down the vent stack and the basement shower today to make sure there are no blockages. BTW, the stench is so unbearable - only when the washer, upstairs shower or dishwasher are used - that you cannot even enter the basement bathroom without a gas mask!

    Attached Files:

  6. Terry

    Terry Administrator Staff Member

    Messages:
    15,050
    Location:
    Bothell, Washington
    What you have is not plumbing if that is how it really is.
    It should look more similar to this drawing below.
    If the fixtures are vented, it prevents the trap seals from siphoning.
    [​IMG]
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,684
    Location:
    Cave Creek, Arizona
    vents

    The way you have drawn it the showers and washing machines have "S" traps and are not vented. The lavatories may or may not be since you do not indicate what kind of traps or the piping behind them. The 1 1/2" vent was installed for some purpose but without knowing where it comes from we cannot tell you why.
  8. artistsnature

    artistsnature New Member

    Messages:
    14
    I believe that the shower and washer are NOT vented; well, I know that for sure about the washer. They are all p-traps, I think - I've just never tried to draw a plumbing diagram, so it didn't come out perfect. The 1.5" vent over the soil stack is the only vent stack on the roof. BTW the whole basement used to stink until I installed the stand pipe trap on the washer - it was previously just a straight run to the horizontal. Now only the bathroom is unusable from the stench....
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