Moisture can cause mold to grow on your fiberglass insulation.
Mold on insulation in basement.
Once trapped there it can lead to mold and mildew.
Dirt that can attach to your insulation includes dust dirt from outside air that does not get filtered well and dirt from construction activity within your home.
In basements similar to the on in this example that means the water vapor in the basement wants to migrate outwards from the basement to the outside of the house.
Basement mold removal on tile or linoleum can also be performed with vinegar or a borax and water solution.
When that happens the vapor can get trapped behind the fiberglass insulation at the backside of the wall sheathing.
Video of the day.
Basement insulation mold busting strategy 1.
But in a more subtle and not easily visible form problematic building contamination by mold is often found in otherwise clean looking basement fiberglass insulation crawl space fiberglass insulation fiberglass wall insulation heating or cooling duct fiberglass insulation and attic or roof insulation in buildings which have either been wet or have been exposed to high levels of mold from other sources.
There are no exceptions to this rule.
This was a typical basement wall assembly with a stud wall directly against the foundation followed by fiberglass insulation and a vapour barrier.
The mold damage you see is from longterm moisture exposure not the one time flooding event.
For nontoxic species of mold and less severe mold growth there are many diy solutions for the prevention and control of mold in the basement.
Dirt and mold can adhere to the fiberglass sheets.