Sunday, April 22, 2012

The Asbestos Drywall

Asbestos drywall from the late 1950s through the 1980s, manufacturers of building materials sometimes incorporated asbestos drywall to strengthen the sheets, aid in sound absorption, and improve fire resistance.  This practice was abandoned following the 1980s, but a large portion of the building materials used during construction during that time period now pose potential health risks.

Asbestos in drywall is the most significant issue to affect the real estate industry since asbestos. About a month ago, I began fielding calls from several regional lenders concerned about their exposure to Chinese drywall. These lenders, pinched by the broader market conditions - foreclosures and depressed real estate values - worry that asbestos drywall will be a hurdle as they try to clear their books of foreclosed homes.

History of Asbestos 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.

Friable Asbestos Drywall

The process of removing drywall causes, by its very nature, creates a great deal of airborne particles. If the gypsum plaster in the drywall contains asbestos then the airborne dust will contain asbestos particles that may be inhaled. Inhaling these particles in a large enough quantity, either all at once or little by little over a long period of time, is the only documented cause of Mesothelioma. Of course, drywall isn’t the only material that might contain friable asbestos during a renovation – friable meaning the ability to become airborne. Piping may have had asbestos sprayed on it. It may have been used in a popcorn ceiling or pretty much anyplace that there may have been a need for extra fire protection. Bathrooms, laundry rooms, utility rooms and kitchens are all prime places to expect asbestos in drywall and underlying fixtures.

Composition of Asbestos Drywalls

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

    Calcium Sulphate (Gypsum)
    Calcium carbonate
    Crystalline Silica
    Potassium Sulphate
    Fiber Glass
    Paraffin Wax
    Boric Acid

Types and sizes of Asbestos Drywalls

Asbestos 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.
  • Regular drywalls are used for walls and ceilings in homes and commercial buildings.
  • 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.
  • Type C (Improved X) has more fire retardant materials added to make them more fire resistant.
  • Green Boards are designed to be water and mold resistant. These drywalls are used in bathrooms in homes.
  • Gypsum Core Boards are special 1-inch thick laminated panels used for shaft walls.
  • Liner Board Sheetrocks are gypsum boards used for separating wall systems. They are usually ¾ or 1-inch thick.
  • Soffit Drywalls are weather resistant and often used for external areas.
  • 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 Asbestos 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
Asbestos Drywall risks and other health related issues

Asbestos 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.
  6. 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.
Due to encapsulation, a paper covering, and layers of paint and/or wallpaper, the risk of asbestos fiber inhalation from existing walls is extremely low.  Dangers arise primarily during demolition and remodeling activities.  When repairing cracks and holes in existing walls, care must be taken when sanding areas where the gypsum core of the drywall or patches of bare joint compound are exposed.  Because most cracks occur at joints, asbestos drywall compound can become airborne easily if the crack is sanded deeply enough to remove the paint or wallpaper completely.

Unfortunately, it is impossible to distinguish by visual inspection alone between drywall with asbestos and drywall without.  Even modern wallboard contains reinforcing fibers, though they are now generally made of cellulose or fiberglass instead.  Asbestos in joint compound is also virtually undetectable with visual inspection.  Only a professional test can determine for sure whether or not there is contamination present.