Wet spot on wall in bathroom
 

Hello,
My house was built in 2010. Recently I have noticed a wet spot on my wall in my bathroom. It's on the wall behind the toilet. The spot is about halfway up the wall. It dries up and comes back and when it's moist that spot on the wall is very cold to the touch. It eventually dries up but returns later. I have no clue where it is coming from. If it helps, my garage is on the other side of this particular wall as well. Please help figure this out. Thanks

Your toilet vent pipe is right there heading up to the roof.

The moisture is ,most likely, from condensation--if so, there is air getting into the wall around the vent/attic penetration.----fix with foam spray.

Could also be a cold spot because the pipe allows cold from the garage---fix is more difficult--

One other possibility--someone tried to hang a toilet topper cabinet or shelf and drilled a hole in the vent pipe.----Have fun with that one----Mike----

I'd also be looking up on the roof to see where the vent is for that room to see if there's exposed nails, a leaking seal around the vent.
Starting at the top and working your way down will not prevent the fact that wall has to be opened up.
If not there will be mold growing inside the wall. The sooner you do it the better, it's not going to get better or go away by waiting.

When you say "recently..." does that mean the last few days or weeks?
Where are you located?
Has there been any significant weather, alteration to garage or bathroom, or anything (a pattern) that may account for the "wet spot"? Since the house was built in 2010, I take it that it has been through the season cycle--- winter/spring/summer/fall a couple of times, and nothing was noticed previously.

Just thinking out loud, hoping (perhaps) to jog your memory. That space behind the toilet and between bathroom and garage should have lots of insulation, vapor barrier etc. And since it dries up, doesn't sound like a constant leak, but as has been said - it may be a roof vent issue???

Well I live in Mississippi and the weather here is very unpredictable. So it's been cold here for a few days this week about mid40 degrees, but mostly it's been in the 70s this winter. My first time seeing this was probably last week. Could this possibly have something to do with it? My house is still under the builders warranty so is this something that they could fix?
Thanks for all the info as well

Yes they should be fixing it and do not let them drag it out!!

I had the same sort of symptoms, wet spot and cold to touch, that turned out to be condensation on the walls -- but it only happened if really cold out (20* or less) and I had the humidifier up too high. Definitely due to lack of insulation in my case.

Didn't add a towel rack or anything did you? Might have nicked a water line? Just a possibility along the lines of having pinholed the vent pipe with the tip of a screw.

Nope I haven't added anything. There is a cabinet above the spot but its been there.

Been there long enough to have a screw onto a pipe and have the screw finally rust off?

Or just rock around to expand the tiny pinhole made by the screw?

You might have to cut a small hole so you can get some light and an angled mirror behind the wall to see what is going on?

Seen that to many times----Holes for anchors drilled into stacks---finish nails into the water lines--Dry wall screws into the pipes--

I just might have done all of the above once or twice myself.

Nope haven't screwed anything in my bathroom walls either.

What's holding up that cabinet above the toilet?