Insulation info

hey everyone, I live in NH and I have been seeing a lot of insulation looking like this. I don’t think it is mold. It seems to be like in the paper. Maybe when the attic gets to hot it become discolored. I call it out as being discolored. But I would like to get to the reason why it is getting discolored. This is in the attic.

Any help ?

Its the heat leaching the adhesive through the vapor barrier.

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Usually the paper turns brown/black from dirt passing by it and getting stuck to it. Usually you’ll see that in the walls and in the ceiling near the walls where the air is drawn thru the walls into the attic.
The paper should not be left exposed as per Manufacture instructions.
Also that framing looks like TJI framing. If indeed it is, the insulation should have been a full 24" wide to eliminate leakage and instead of kraft faced insulation, they make a flame resistant foil faced FSK insulation for that condition.
Is that a knee wall construction I see with the knee wall open to the rest of the attic?

Yes that is a knee wall it is also insulated. With craft paper towards the drywall.

I thought it may be the tar like adhesive on the back of the kraft paper leaching through just a thought.

That would make sence also. But how does it leach though? It not everywhere just is some places in that area.

It could be leaching through the paper if it is hot up there. Hard to tell from those pictures.
But the insulation doesn’t look like it is installed properly.

Here are a few pics on knee walls in attics that may help.

It looks like that R-30 insulation was shoved tight in the framing space, which is not right, it needs to ventilate above it from the eaves to the ridge to reduce the amount of heat up there. That may have something to do with it.

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Thank you for your help. that makes a lot of sense! the R-30 was shoved in between the rafter. between the sheathing and the insulation, there was baffles vents going up the ridge. ( I think I could not see all the way up.) but the part I could see was behind the insulation. but there was no separation between the knee wall and the rafters.
so going back to your first response. air is getting pulled for living space and from attic space and is going out the ridge and soffit vent or the other way around. causing that dirt to get stuck on there? And/or making the adhesive to discolor and/or fail?

Well, hopefully it’s starting to make sense to you. Sounds reasonable, but we are not there.
Makes sense it is one of those problems.