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Paint bubbling of the bathroom wall.

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  • Paint bubbling of the bathroom wall.

    On the header wall for the bath tub shower in the master bath, (This is not an outside wall) the enamel paint began bubbling and pulling off of the sheetrock. There is (WAS) no access door there. My moisture meter showed about 15% - 18% moisture in the sheet rock. I cut out a rectangular section (24” by 32”) which is just beyond the edge of the paint peeling.

    • When I looked inside, there was no evidence of moisture leaks from any pipes. Surprise, surprise. And no mold, of which I was fully expecting.

    • There is an opening under the tub to the sub floor (concrete, about 16 inches below the room floor).

    • No evidence of a pipe leak or tub/shower wall leak.

    Now, to my observant probable cause and I need help from the experts here if this IS probably the cause:
    1. There is an air duct off to the side and almost in line with that wall. I keep it almost closed because it blows too much (heat and cold air) there when fully open.
    2. LOML had me put a 48 x 16 mirror there about 5 years ago. It hung against that wall. Half of the paint bubbling/pealing was behind the mirror but it extend out beyond the mirror on one side.
    3. I am surmising that some ground humidity soaked into the wall from the back side due to the humidity swings; or the mirror prevented the air flow behind it and in some manner a light coat of “sweat” due to temp & humidity changes with restricted airflow developed, causing the paint to bubble off and the sheet rock to retain moisture.

    Does my assumptions sound plausible?

    Now I have to make a Nice Looking Access Door for the to please LOML! That isn't going to be easy as it will not be symmetrical!
    Hank Lee

    Experience is what you get when you don't get what you wanted!

  • #2
    This may or may not help but:

    I recently had to deal with a DIY shower unit where the tile grout was not sealed properly. My bro-in-law (who does tile work for a living) and I had to seal the grout, caulk the corners of the shower and replace the damp, moldy drywall.

    Your situation is obviously not as serious, but could it be that just enough humidity is getting into the wall to cause such a problem? It might even dry up between showers.. I recommend running the shower for an extended period, then immediately check the humidity.

    Hope you figure it out.


    • #3
      Thanks. I will do that.

      I have an access panel there now - that even LOML approves of. Getting her approval of the access door design was a bigger worry to me than the paint pealing off.
      Hank Lee

      Experience is what you get when you don't get what you wanted!


      • #4
        You shouldn’t beat yourself up too bad over some paint problem. I’ve seen plenty of paint problems that had nothing to do with the application or environment. Paint has evolved from the being lots of good paint manufacturers to a few giant companies that also manufacture paint. Every brand has numerous grades and boasts that they will cover anything. Who knows, your bad paint could be some that too much of something and not enough of something else. In any manufacturing process dealing with the sheer volume of liquid they are blending an mixing, there is always a chance that everything isn’t getting mixed completely or not enough components added in.

        Earler this week I purchased a quart of paint, the paint mixer person choose a can off the shelf with the correct base to suit the color, added several colors and shook the can till the label nearly fell off! Within 2 hours I was smearing it on a board. About an inch into the can I noticed several streaks of color in the liquid so decided to stir it just for kicks! Wow, it didn’t look like this paint had been mixed at all. I hadn’t bothered stirring it when I opened it because the store had just shaken it. So much for paint shakers.