Types of Drywall and How They’re Used

There are a lot of different kinds of sheetrock, drywall, gypsum board or wallboard. Besides the typical general use drywall, it also comes in moisture-resistant, mold-resistant, fire-resistant, noise-reduction and more.

Drywall is gypsum plaster between paper layers. To create a sheet of drywall, gypsum is pressed between two thick pieces of paper and then kiln-dried.  It is called drywall because it was used instead of lathe and plaster. Plaster was wet. It had to dry before the next step in construction.

Sheetrock is the brand name of drywall made by U.S. Gypsum.  Like Kleenex, people use it for any brand. Drywall was invented by Augustine Sackett. He patented it in 1894 and named it “Sackett Board.” U.S. Gypsum bought the patent and started making it in 1916 in the form of small fireproof tiles. By 1917, they were making large panels marketed as Sheetrock.

Sheetrock took off in the 1950s because it was so much faster and less expensive than lathe and plaster.

Before long different types of paper layers and different additives to the gypsum plaster were developed for specific needs.

Standard White Board

Standard whiteboard is only for interior use. It is available in the most sizes and thicknesses. It is typically 4-feet by 8-, 10- or 12-feet. It is usually ½” thick, but it also comes in ¼”, 3/8”, ½” and 5/8” thicknesses.

Other types of drywall are more expensive, but using the right product for the project is worth the extra cost.

Moisture Resistant Green Board (or Greenboard)

Moisture-resistant greenboard has a moisture resistant paper coating. It is for interior areas that may be exposed to water, like kitchens, bathrooms and laundry rooms. It is for damp, not wet locations.

Mold and Moisture Resistant Purple Board

Purple Board offers enhanced mold and moisture proofing. It is used for high-humidity areas and areas that may be directly exposed to water splash, like above tubs and showers. For even higher moisture areas, use cement backer board.

Paperless Drywall

Paperless drywall is a relatively new product. It has fiberglass mat instead of paper over a more water-resistant gypsum core. It is more moisture, mold, and mildew resistant than purple board. It requires a full skim coat instead of just taping and skimming the seams.  It is more durable than standard white drywall, resisting dents, warping, and tears. They make a paperless drywall tape to use with it.

Paperless drywall is appropriate for bathrooms, kitchens, basements and garages. It is not for areas exposed regularly to water, such as inside a shower stall.

Fire Resitant Type X/C

Fire-Resistant X and C drywall have a thicker, denser gypsum core with glass fibers added. They are not fireproof, but slow the spread of fire with less smoke giving occupants more escape time. It is for furnace or wood stove areas or garages. It is used between units in townhouses and condos. It is sometimes required by building code.

• Fire Resistant Drywall Type X has a one hour fire resistance rating.
• Fire Resistant Drywall Type C has a two + hours fire resistance rating

Soundproof Drywall

Soundproof drywall is denser for noise reduction. It significantly reduces sound transmission by trapping sound waves. It is thicker than standard drywall, with two gypsum layers glued together with a noise-dampening viscoelastic compound, like Green Glue adhesive. Some incorporates other sound-absorbing materials like ceramics or mass-loaded vinyl sandwiched between the gypsum layers.

Cement Board (Tile Backer)

Cement board tile backer is concrete-based, made from cement and silica.  It is used in wet areas like showers, then covered with tile.

Plaster Baseboard (Blueboard)

Blueboard has a special paper coating designed to bond well with plaster. A plaster surface is applied using the drywall as a base. The blue paper surface of the drywall draws moisture from the wet plaster and chemically bonds for a super-hard, durable wall.  The plaster can be smooth or textured.