Center for Asbestos Safety

The history, uses and risks of Drywall

Drywall, also known as sheetrock, wallboard or gypsum is the most commonly used building material in commercial and residential construction in the United States. Drywall consists of a layer of gypsum covered by heavy paper on both sides and is used to cover the surfaces of internal building walls. The invention of drywall in the early part of the 20th century revolutionized the construction industry and lowered the construction costs. However the material can pose health risks to installers if they fail to take adequate precautions.

History of drywall

Before 1940, builders often used three layers of plaster laid over lath boards to cover inner walls of residential and commercials buildings. The first layer created a flat surface, the second smoothed the surface and the last one was the actual wall. The three-part process was laborious and time consuming because each layer had to be applied and then allowed to dry before adding the next one.

In 1916, the United States Gypsum Company invented the original Wallboard. This was made of a layer of gypsum covered on both sides by thin flexible papers which added strength and flexibility. The new material had numerous advantages over the plaster method. It was easier to manage, could be nailed immediately to the frame to create a wall, cut into smaller sections as needed and used dry without the need for setting, hence the name Drywall.

The material began to see widespread use after World War II when builders began looking for ways to lower the cost of construction during the rise of suburban areas. The advantages of drywall over plaster made it the material of choice and it can be found in 95 percent of homes and commercial buildings in the United States.

Composition of drywalls

Drywall is composed of minerals found naturally in rocks. Common components found in drywall include the following:

  1. Calcium Sulphate (Gypsum)
  2. Calcium carbonate
  3. Cellulose
  4. Crystalline Silica
  5. Vermiculite
  6. Potassium Sulphate
  7. Starch
  8. Mica
  9. Fiber Glass
  10. Paraffin Wax
  11. Boric Acid

Types and sizes of drywalls

Drywalls are classified according to their resistance to various elements. Manufacturers cut the gypsum boards into various sizes with some of the most common being 4x8, 4x9 and 4x12 feet. Commonly used thicknesses include 3/8 inch, ½ inch and 5/8 inch with ½ inch.

  1. Regular drywalls are used for walls and ceilings in homes and commercial buildings.
  2. Type X drywalls have fibers added to them to make them fire resistant. These are used near kitchens in homes and anywhere fire resistance is a top priority.
  3. Type C (Improved X) has more fire retardant materials added to make them more fire resistant.
  4. Green Boards are designed to be water and mold resistant. These drywalls are used in bathrooms in homes.
  5. Gypsum Core Boards are special 1-inch thick laminated panels used for shaft walls.
  6. Liner Board Sheetrocks are gypsum boards used for separating wall systems. They are usually ¾ or 1-inch thick.
  7. Soffit Drywalls are weather resistant and often used for external areas.
  8. Sheathing Drywalls are used in external walls for structural integrity and fire protection. It is available in treated and non-treated forms for water resistance.

Tools and materials for installing drywalls

Construction workers like drywall installers, tapers and ceiling tile installers install drywall using the following tools and materials:
1. Drywall Screws
2. Wooden Wedges
3. Sandpaper and Drywall Tape
4. Measuring Tape
5. Chalk Line
6. Dust Mask
7. Utility and Taping Knife
8. Screw Gun
9. Keyhole Saw
10. Straight Edge
11. Joint Compound or Mud
Drywall risks and other health related issues

Drywall installers can develop health problems from exposure to the material over a prolonged period of time. The following health problems are associated with long-term exposure to drywall:

  1. Drywall dust can become airborne and cause irritation and inflammation when they come in contact with the eyes. In some cases medical attention may be required.
  2. Drywall dust can cause skin irritation.
  3. Inhaling drywall dust can lead to the development of throat and lung problems. It is recommended that installers wear masks/respirators when handling drywall.
  4. Drywall contains crystalline silica and continuous inhalation can cause Silicosis, a serious lung disease. Mica, another component of drywall is a known cause of Pneumoconiosis, a fatal lung disease.
  5. Other diseases associated with long-term exposure to drywall dust include tuberculosis, kidney and renal diseases, thickening of the skin, lupus and rheumatoid arthritis.
    To avoid risks associated with drywall, avoid breathing drywall dusts by using respirators, controlling dust during use and disposal and using HEPA rated vacuums or wetting drywall dusts before vacuuming.

Center for Asbestos
Safety in the Workplace