Green Drywall Vs. Plaster in Bathrooms

Green Drywall

• Green drywall, also called greenboard, is not named for its eco-friendliness, but the light green paper covering it. This product is designed to resist moisture where it is installed. This makes it useful in the elevated humidity of a bathroom. Some green drywall might be treated with mold-inhibiting or mildew-inhibiting compounds to make it mold or resistant in addition to moisture resistant.

Plaster

• Plaster is not commonly used in modern bathrooms due to its difficulty in its installation, but it wasl commonly used throughout the house in homes built prior to the 1950s, when drywall became more prevalent. (see reference 2 pg 5)You will need a network of metal laths over the frame inside the wall to which to apply the plaster. It will take several coats before the plaster is thick enough for your walls. The top layer can be textured or left smooth and painted.

Problems with Plaster

• You should not use plaster in a bathroom with a shower or bathtub. The high humidity levels created when the tub or shower is in use can damage plaster walls. Plaster can crack or sag, especially in areas that experience changes in moisture levels, such as bathrooms. Small cracks are easily repaired by the homeowner, but a professional should work with sagging ceilings to repair or replace the plaster. (see reference 4 pg 257)

Problems with Green Drywall

• Green drywall cannot be used everywhere in a bathroom. It will break down if used in areas where direct contact with water is likely, such as around the shower compartment or directly above a tub. To avoid problems with moisture being trapped behind the drywall, do not install it over a vapor barrier insulation or non-breathable products. This creates a double seal, that does not allow the wall to breathe and excess moisture to evaporate. (see reference 2 pg 9)