[Jpepper]

Hi there

This isn't really a DIY question as we don't intend to fix this issue ourselves since we have a feeling it is black mold, which totally freaks me out. Here's the situation:

We bought a 17 year old home this past July. Prior to purchase, we had a full professional inspection done on the house. Today, when leaving for an errand, we noticed some brown liquid coming from the soffits above the bathroom window and travelling down the siding. When we returned home, we immediately checked out the attic and noticed a large section of the roof sheathing is black! Without going entirely into the attic area, we cannot fully see what is going on. After a bit of internet research, we are left wondering if the bathroom fan vent(s) was not installed properly and is thus creating a condensation/moisture problem in the attic area.

Hoping someone can give us their thoughts on the situation??

Thanks

 

[griz]

You can test the mold yourself, Prolabs out of Florida. Most home improvement stores have the test kits.

It is quite possible that an improperly vented bath fan has caused the situation. There may be other ventilation issues that need looking at.

 

[SPS-1]

For sure improperly vented bathroom exhaust can cause mold on attic sheathing, but hard to imagine so bad that it drips down your siding. From your photo of attic it rather looks like sheathing one joist beside has little or no mold. So could be a water leak from the roof. Possibly flashing of a plumbing stack.