Bathroom Wall Condensation

Past Friday inspection. The upper bathroom had condensation on the walls running down from the ceiling about a quarter the way down.
The rain had stopped about one hour prior to me getting to the bathroom. Outside temperature was 76*F
The house has been empty for the past two weeks. The AC was on, thermostat set at 73.
Window only opened to test and closed again.
There was a jacuzzi tub, shower stall, toilette and sink. I ran the tub until the jets were submerged for testing. I did not use hot water. I ran the shower, used hot water, not long enough to steam up the stall walls, and ran sink water hot and cold. Not long enough for steam.
The bathroom exhaust did terminate into the attic (aluminum flexible duct was ended about five feet from fan) and was running the entire time I was in the bathroom.
Why so much condensation?

I would suspect the attic is building up condensation from improper ventilation, also if the gypsum is not the proper rating it could be holding moisture as well, another hypothesis is if the chimney connects to that wall and has deteriorated joints.

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Was the condensation on the walls “when” you arrived? or developed during the inspection?

I didn’t notice until I was there for about 30 minutes. The walls are a light color.

Not enough information… obviously from condensation but specifically how and why will just be a guess until you go there, duplicate the issue and gather more info. Next time I’d pay closer attention to if the walls were sweating before you arrived :slight_smile: Perhaps someone took a shower or turned on hot water before you arrived. You never know what someone does in the “vacant” house before you arrive! I had been to houses where a homeless person would live, and shower, while the house was being shown to clients. The homeless person would leave before anyone showed up. Yes, it was arranged so by the listing agent. I’m saying… you just don’t know, don’t assume nobody did anything before you arrived just because the agent told you the house was vacant for 2 weeks. You were not there for 2 weeks to assure this to be a fact! Just like you don’t assume nothing is broken just because an agent told you :slight_smile:


You must have more time to do an inspection than I do…sounds like you were taking a shower in there…lol…which might be a good way to test the system but I’m pretty sure it goes beyond the standards of practice…

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You said the AC was on. Was the vent in the bathroom open? Was the door open or closed? I keep the T-stat in my house at 73 during the day and my master bath gets down to 60, making the walls cool enough to show some condensation after just a few minutes of warm/hot water running.