This is a mystery - leak or condensation?

Discussion in 'General Plumbing Help' started by jeffw_00, Mar 31, 2019.

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  1. Mar 31, 2019 #1

    jeffw_00

    jeffw_00

    jeffw_00

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    Hi - We have a standard bathtub with tiled walls. There is a small hatch for access from the finished basement centered around the drain plug. We are getting water (several ounces after a shower) through the hatch. BUT - the details are interesting:

    a) it happens ONLY after a long steamy shower. Long baths, short showers, & long-not-steamy-showers produce no leak..

    b) We hung sheet plastic on the front (plumbing) wall and long-side of the tiled tub area, using shipping tape to attach to curtain, and also to seal along where the tub meets the tile. This had -no- effect. (although the tiled plumbing wall behind the plastic still got damp after a long steamy shower).

    c) from below we can see the water appears to be coming from the front-right area (to the right of the spout) - it's possible the source is behind the plumbing wall.

    d) There has -always- been a small area of the regular (plastered blueboard) wall to the right of the front of the tub (about 3" wide and the height of the tub) where the paint rots over time. Moisture behind the wall would explain it, but no plumber has been able to explain why this occurs. (Note - we've even had the bathroom torn to the studs and rebuilt once (to replace the tub 15 years ago)).

    e) The bathroom is 5' x 8' and has an oversized (200cfm) exhaust fan that always runs during the shower and for a time afterwards. It vents to the attic near a 3' x 3' gable vent (so essentially to the outdoors).

    It doesn't seem like water from the shower is somehow getting directly through the wall. It rather seems like the steam created by the shower somehow causes moisture to condense and drip behind the wall, but I can't come up with a working model in my head to explain the behavior.

    I really want to do all the testing I can, to have a clue what is going on, before I call a plumber.

    Any/all ideas much appreciated.

    Many Thanks!
    /j
     
  2. Mar 31, 2019 #2

    Geofd

    Geofd

    Geofd

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    in paragraph d you mention an area of blue board were the paint keeps rotting over time hve you though about changing that to green board or dur rock?????
     
  3. Apr 1, 2019 #3

    jeffw_00

    jeffw_00

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    right now I would prefer to first understand why it acts like there's water behind it
     
  4. Apr 1, 2019 #4

    Geofd

    Geofd

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  5. Apr 1, 2019 #5

    Geofd

    Geofd

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    the blue board im guessing is just out side the tub on the lip??
     
  6. Apr 1, 2019 #6

    jeffw_00

    jeffw_00

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    yes - immediately to the right of the front of the tub - damp from about 5" above the floor to 5-6" above the top of the tub
     
  7. Apr 1, 2019 #7

    Geofd

    Geofd

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    pics are easier to see but I think your dealing with over spray water leaks off the tub rim down onto the sheet rock soaking it over time causing a leak behind the wall water will find its way down to were you see it....there are corner pieces that have double sided tape that you would stick to the tub lip and the tile part of the wall show some pics if im missing what your explaining....
     
  8. Apr 2, 2019 #8

    jeffw_00

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    Hi - thanks - that corner is dry - we do have a corner piece, also for now the shower curtain is continuous to the plastic on the back wall , and there is shipping tape over the seams. Up to this morning I had though it was the steam leaking behind the wall and causing condensation, but today my wife took a not-so-hot, albeit long, shower with the window open (so no steam buildup), and it still happened. In a different forum someone suggested capping the shower spout, turning on the water, and seeing if there was a leak - I may try this - it's possible there is a small leak in the pipe to the showerhead that has finally gotten bigger. It doesn't explain the area where the paint decays, but I have that in my other bathroom as well and so may be an unrelated issue.
     
  9. Apr 2, 2019 #9

    sawguy50

    sawguy50

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    Sounds to me that it could be coming from your exhaust fan plumbing. Condensation running back down the vent pipe into the ceiling perhaps and down the wall. maybe get into attic and make sure the vent pipe is securely attached to the fan. If it isn't vented through the roof, it could also be dripping from the underside of the roof (condensation) onto the ceiling.
     
  10. Apr 2, 2019 #10

    jeffw_00

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    Exhaust fan is not over the shower and exhausts directly into flex vent pipe into the attic above a finished floor - and actually into a large plastic container that has a screened opening on the far side (to catch lint that is sucked up into the exhaust). No path from the exhaust outflow back into the walls.
     
  11. Apr 2, 2019 #11

    Geofd

    Geofd

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    I have seen leaks from shower arms remove the shower valve plate turn the shower on and see what you can see or just remove the shower arm and replace with new....is there a gap were the tub spout meets the wall...is the over flow plate tight...is the shower valve plate tight is there a foam strip behind the shower valve plate
     
  12. Apr 2, 2019 #12

    Geofd

    Geofd

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    is your grout/caulking in good shape
     
  13. Apr 2, 2019 #13

    sawguy50

    sawguy50

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    He said only after steamy showers, thats why the exhaust fan theory.
     
  14. Apr 3, 2019 #14

    jeffw_00

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    caulk is in good shape, and caulked around spouts and controls. Grout -looks- ok, was sealed 15 years ago. Interestingly - a long not-so-hot shower with window open (so no steam) did not change things. So I was wrong...it's not the steam, it's simply the length of the shower.

    I'm inclined to remove the showerhead and cap it, and try running the water. It might be a small leak that generates enough water to drop below only when it's run a long time. (argh - a leak in the pipe behind the wall) :-(

    Thanks for all the help so far. Might not get to doing the cap experiment until the weekend...
     
  15. Apr 3, 2019 #15

    Geofd

    Geofd

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    do you have a window in the shower????
     
  16. Apr 4, 2019 #16

    jeffw_00

    jeffw_00

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    window is at opposite side of bathroom
     
  17. Apr 8, 2019 #17

    jeffw_00

    jeffw_00

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    Capping the shower head has been inconclusive. I recreated the leak once but on subsequently attempts (inlcluding the one where I got the right kind of cap so it was tight) things were dry. So I still don't know if it's coming through the wall or from plumbing behind wall. However, when it leaks, we can see that the water appears to be running down the outside of the tub. I've been able to put paper towel on a wire hanger up into the space - next to but not touching the side of the tub. and next time my wife takes a long shower we will see if it gets wet, or if not, hold it against the side of the tub and see if the side of the tub is really wet. That should help discern if it is dripping from the plumbing or running through a crack/hole in the enclosure.
     
  18. Apr 13, 2019 #18

    jeffw_00

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    water is running down the side of the tub - time to call the plumber
     
  19. Apr 13, 2019 #19

    Geofd

    Geofd

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    the outside of the tub?????
     
  20. Apr 13, 2019 #20

    Geofd

    Geofd

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    tape your shower curtain to the wall were its leaking onto the floor use the shower if it stays dry its over spray
     

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