[perpetualjon]

I'm in the process of repairing some mold damage in one of my bathrooms. Mind you, there is no exhaust vent yet installed in this bathroom (yet). I noticed this on the back side of the drywall to this bathroom when I opened up the same wall from the outside hallway to start some wiring work...

I don't see any indication of water damage on the inside of the bathroom walls here but is it possible that moisture is seeping through the paint and coming out inside the walls at the seams? Since I'm almost half-way there, I may just go ahead and remove all the drywall in this bathroom but I'm just tying to minimize unnecessary work here... Any thoughts?

 

[bjbatlanta]

You're getting water intrusion from somewhere. If there's mold on the other side of the drywall in the same places as the stains on the back side, I'd replace it. Odd that it's more pronounced at the tapered edge seams and the framing. Definitely get a proper exhaust fan in there!

 

[Scuba_Dave]

Is it a tiled bathroom?
Surround kit?
Possibly they put the drywall up & never taped the joints

 

[bjbatlanta]

The joints would all be cracked without tape and moisture will go through the tape too. I can understand the water running DOWN a stud if there's leak. Running horizontally with the tapered edge though??

 

[Scuba_Dave]

What I meant:
If they put tile or a surround up they may have just put the sheetrock up & that's it. No tape, no mud, nada
I've seen it done....

 

[perpetualjon]

Well I may never know what caused this situation but I'm pretty much accepting the fact that I'm going to be replacing ALL the drywall in this bathroom (and probably replacing the drywall around the tub surround with tile...

 

[PaliBob]

Around here (So CA) the Drywall suppliers now carry National Gypsum Purple Board in two varieties ½” XP and Hi-Impact ⅝” XP.
http://www.negwer.com/News/ViewNewsItem.aspx?id=503

It also has better specs than greenbord for use on ceilings in that 16" joist spacing is OK with XP.

 

[Maintenance 6]

Well I may never know what caused this situation but I'm pretty much accepting the fact that I'm going to be replacing ALL the drywall in this bathroom (and probably replacing the drywall around the tub surround with tile...

If you're gonna replace it, then I'd go with GP Densarmor paperless. Nothing for mold to live on.

 

[PaliBob]

Nothing for mold to live on.

Maint, is correct on this but I don't like to use DensArmor® Plus because unless you are going to use a completely flat paint, you need a level five finish.

Here is some info on Mold Resistant Gypsum Panels:

from:http://www.toolbase.org/Technology-Inventory/walls/mold-resistant-gypsum-panel
Mold growth requires moisture and a food source. Therefore, some gypsum board manufacturers have developed products with gypsum cores that will not absorb moisture as easily as typical gypsum board. To reduce the risk of mold growth that paper facings can provide, a number of manufacturers, including U.S. Gypsum (Sheetrock® Brand Humitek®), National Gypsum (Gold Bond Brand XP), and Temple-Inland (Silent-Guard™ TS gypsum shaftliner), chemically treat the paper on both sides of the gypsum board. Some manufacturers eliminate the paper entirely. Georgia Pacific (DensArmor® Plus) replaces the paper with glass mat facings, while U.S. Gypsum (FiberRoc® AquaTough™) uses a gypsum-cellulose combination in their panels that doesn't require paper.

 

[tn3sport]

I hear the Chinese are making a pretty good drywall product now...:no:
Kidding...There's reports that Chinese drywall is toxic. Stay away from it.

It actually looks like the drywall might have gotten water stained before it was installed. It usually comes in pairs taped together and the stains look like mirror images. You know how sometimes they just store building supplies stacked up in the garage or somewhere like that during construction, laying on the floor, before it gets installed... Just a thought...

 

[LeviDIY]

Around here (So CA) the Drywall suppliers now carry National Gypsum Purple Board in two varieties ½” XP and Hi-Impact ⅝” XP

PaliBob - that purple board in 5/8" variety would have been helpful to me in this scenario:
http://www.diychatroom.com/f19/5-8-fireboard-paint-meets-1-2-cement-board-tile-42557/

 

[Gary in WA]

Maybe taped with really wet mud and then covered with surround so it couldn't air dry out - moisture went in? If so, that's a wallboard joint on that stud. Be safe, GBAR

 

[perpetualjon]

Be safe, GBAR

Is that an acronym for something?

 

[Gary in WA]

It is. Gary Builds and Remodels, LLC. I help others on other sites as well. One day I Google'd it, and gay bar locations came up. After that, and on the other sites, I'm just GBR. Be safe, G

 

[Ininkus]

It appears to be going horizontal and vertical, but always along the seam... I suspect TN3SPORT is right and that happened before the drywall went up.