Fiberglass insulation in a crawl space tends to soak up moisture and humidity, goring mold and eventually causing it to "drip" off the ceiling, as seen in this picture. And even when it's where it belongs, wet fiberglass is a poor insulator. Our team got rid of the old insulation and replaced it with SilverGlo™ Crawl Space Wall Insulation in addition to TerraBlock insulation.