Can anyone tell me what I’m dealing with. The black staining all over the insulation is throughout the attic. The substance feels wet and sticky to the touch. The above sheating is dry and no signs of leakage. The insulation is 12" thick batts.

How about posting a picture of the underside of the roof?

Well it looks nasty enough.
Definitely get rid of and l think the ventilation in the attic may be suspect and causing it to sweat and drip down.

Beat me to it!

Here’s an article that talks about a possible cause

I saw something like this once but it was more localized. What I ran into was rosin dripping from the rafters onto the insulation. Any new wood up there?


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