Is it the moisture stain?

[Peter Louis]

The pics are the garage attic insulating the living space next to it. I am wondering these lower part of fiber glass batt moisture stained. It is dry at inspection. But where is that much moisture coming from?

Thanks

[Ian Page]

It actually looks more like the batts were acting as an air filter as opposed to a wet condition. However, unless there is other evidence of moisture i.e. discoloration of the surface behind and or above the batts, on the framing members or on the drywall below in the ceiling area, I would suspect it may have been installed that way. Who knows what the installers did or where the batts came from - they could have been laying in a truck during a rainstorm for a few days. They may have also been intalled prior to the roof being completely buttoned up during construction.

ip

[Eric Barker]

It's just dirty and dust - no worries.

[Peter Louis]

Thank you guys. I thought it was dirt. But I report it kinds of moisture stain & ask the owner. Obviously this is a dumb reporting.

[John Kogel]

It's OK to be suspicious, because there could have been a problem there. The fact is, we don't know what caused the stains. Black stain from mould will occur on wood or drywall, but you won't see it growing happily on fiberglass - no food there.

[Eric Barker]

Black stain from mould will occur on wood or drywall, but you won't see it growing happily on fiberglass - no food there.

Actually, mold/fungi can grow on any surface that has residue or dirt on it. So, in Peter's photos mold growth is certainly possible with the proper conditions. But I still would not worry about it.

[brent lerwill]

This condition is not uncommon in attics (common walls or ceilings) and usually means there is air leaking through from inside the house. The fiberglass acts like a furnace filter and catches dirt, soot or other "impurities". Usually there is some moisture coming through from the living space which helps these impurities adhere to the fiberglass. This is a clue that you have a house leaking air through gaps around outlets, switches, light fixtures, etc. need to be sealed. This type of staining is one of the clues an energy auditor looks for.

[John Goad]

Was there a bathroom on the other side?
That could be behind a fiberglass tub/shower where there is no sheetrock & as others have stated is from air infiltration.

[Matt Fellman]

I've seen insulation come right out of the bag looking like that too so you never really know.

Funny staining/marks on insulation catch my eye all the time. There's a funny imperfection that occurs fairly often that makes it look wet but it's not. I think when they are spinning (or whatever they do to the fiberglass) sometimes pieces get clumped together.... kind of like when you make spaghetti and some noodles stick together. The result is a darker pink color in a spot or two.... which looks wet from a distance.