Mold on insulation often appears as black, brown, or greenish discoloration and is accompanied by a musty, dank odor.
To install insulation in a crawl space, cover the vent openings with crawl space vent covers, seal the rim joists with rigid foam board insulation, and use foam sealant to seal gaps between the crawl space wall and sill.
Attic insulation should generally be 10 to 14 inches thick, depending on the R-Value needed for your region.