Redoing shower wall/tiling after mold/water damage

[dtaylorl]

House built in 1982, got water behind the tiles in the bathroom which were adhered directly to drywall. I ripped the tiles and moldy drywall out, and am trying to determine if I need to replace the insulation as well. Attached photos show what the insulation behind looks like.

My initial thought was that it is moldy, but after reading around a bit I guess it’s somewhat normal for insulation to end up like this because of dust/air moving through the insulation. Any idea which I’m dealing with here, or how I can determine for sure?

It’s an exterior wall if that makes a difference, and there is a window on that wall. The wood looks fine to me, just a bit of black which you can see in one photo (the other darker black is tar I think?). So I’m thinking the moisture never made it through the vapor barrier which I’m hoping is a good sign.

 

[WorthFlorida]

It's hard to tell from pictures but I think you are right, it is just from air movement and the fiberglass acts as a filter. I would remove it all so you can inspect the exterior wall from the inside to look for gaps, rotted wood, etc that could allow air to enter the wall. DO replace the vapor barrier with one sheet and tape it to the adjoining plastic sheeting. If it were mold the fiberglass would normally be damp or it is just dried up mold.

 

[Sponsor]

 

[dtaylorl]

Thanks. If I don’t have an issue with drafts or high energy bills do I need to worry much about air sealing? I’ll probably still remove some of the insulation to make sure there are no major issues, but if it’s not moldy could I just put up a new vapour barrier and reuse the existing insulation?

 

[Maximus_Slime]

In my zipcode, I'm 99% confident code no longer wants the plastic vapor barrier because it seems to trap moisture in the walls. Check yours.

I'd be inclined to investigate why those batts of insulation look the way they do. I personally wouldn't re-use that dirty old stuff.