Greenboard is a type of drywall that is coated with a green-colored paper. This green paper is treated with an oil-based additive that makes the drywall more moisture resistant. This is the kind of drywall that is most commonly used in bathrooms and other high-moisture areas. By reducing the absorption of moisture and humidity, greenboard helps to prevent growth of various bacteria, including mold and mildew.

Walls around shower and tub areas or that form the surround walls should be covered with cement board. This is more moisture-resistant than greenboard. Cement board is also the perfect base for ceramic tile. In some areas and some homes, Blueboard is used in bathrooms. The blue paper that is the outer layer of the drywall bonds with a “skim coat” or a built-up plaster finish. This finish resists both moisture and mold.