Humidity or wet air and moisture were trapped behind moldy drywall in a massive commercial building we inspected in North West Florida. Encapsulating moldy drywall is typically a bad idea, encapsulating drywall and moisture in a 50,000 square foot building is even worse. The builder wanted to encapsulate but we told him no, you should conduct proper remediation and remove the drywall, dry the wall cavities, and re-install drywall.