Q. How can I tell if I have Chinese drywall in my home?
A. In some houses containing defective Chinese drywall, a distinctive sulfur odor ("rotten-egg," or chemical smell) and the blackening of certain metals, particularly copper, have been reported to occur.
However, these symptoms can also result from other causes. The only way to be certain that defective Chinese drywall is a cause is to check for labeling on the back of the board to determine its origin and to have the board tested.
Q. Can the sulfur odor and blackening be caused by something besides drywall?
A. Yes. Among other things, water could be an issue. For example, reactive sulfur compounds are found in water in Florida. These compounds can cause foul odors and pitting on plumbing fixtures. A hot water heater can also be a source of hydrogen sulfide gas if there is sulfur in the water and the heater contains a magnesium anode control rod. That problem may be resolved by replacing the magnesium rod with one made of aluminum.
Q. If I have pulled back the insulation in attic and I see the drywall is produced by a domestic supplier, does that mean I have no Chinese drywall in my home?
A. Unfortunately, the answer is not that simple. Some houses have high-strength U.S. manufactured drywall in the ceiling, but not in the walls. Because of fire-rating requirements, you would also typically find U.S.
manufactured drywall in garages.
We are not aware of any high-strength ceiling board being imported from China. It is also common for drywall in the same house to have been made by two or more different manufacturers. For example, a residential drywall installer may call a supplier and ask for a specific quantity of drywall in a certain width and length. The supplier, who likely handles several different brands of drywall, will often send what is on the shelf in his warehouse to the job site. This shipment could include drywall from a number of different manufacturers. Or orders from the installer may be placed on more than one date, and a different manufacturer's drywall may be shipped at different times.
Domestically manufactured drywall is marked with the manufacturer's name and, in most cases, the location, date, and time it was produced. In addition, U.S. produced will be marked with ASTM codes and UL certifications. Some Chinese drywall has the manufacturer's name on the back, some is marked with "Made in China" and some has no markings at all.
For further information, you may wish to check the website of the Consumer Product Safety Commission: http://www.cpsc.gov/info/drywall/hud10068.html
Some Chinese drywall has the manufacturer's name on the back, some is marked with "Made in China" and some has no markings at all." For more information about the Chinese drywall issue, read this overview by the Gypsum Association.
You may also wish to check the website of the Consumer Product Safety Commission for additional homeowner information."