Answer: Your best source is our guidance (pdf) on identifying homes built with problem drywall. (There are many reasons that a home could exhibit similar symptoms to a home with problem drywall and it is important that you correctly identify the source at work in your particular circumstance.)
Briefly, the identification process for identifying whether problem drywall is present in a home is a two-step process.
Step One: A visual inspection must show:
- Blackening of copper electrical wiring and/or air conditioning evaporator coils and
- Drywall installed between 2001 and 2009
If both of these are present, look for corroborating evidence.
Step Two: Corroborating Evidence: (if drywall was installed between 2005 and 2009, must have at least two of the below. For installations between 2001 and 2004, at least four of the following conditions must be met:)
- Elemental sulfur in the drywall core (requires outside lab testing)
- Copper sulfide on coupons, grounding wires, and/or air conditioning coils (requires outside lab testing)
- Chinese markings on drywall (This does not imply that all Chinese drywall or that only Chinese drywall is associated with these problems, but that among homes with the characteristic corrosion, Chinese drywall is a corroborating marker for the characteristic problems.) Such markings may not be present or easily discerned in all problem drywall homes.
- Elevated sulfide gas emissions from drywall (requires outside lab testing)
- Corrosion induced by drywall in test chambers (requires outside lab testing)
If your home has problem drywall, see our remediation guidance (PDF).
The back-side of this drywall (not normally visible to the resident) is labeled "MADE IN CHINA."
Note: Not all drywall from China is problem drywall.
The ground wire connected to the green screw is blackened and corroded.
This wire should be copper-colored.
The copper coils on this air conditioner unit are blackened and corroded.
This copper pipe is blackened.