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Step-by-Step Self-Assessment Guide for signs that a home may be affected by drywall imported from China.
This self-assessment guide has been developed for people to
determine if their home is showing signs of corrosion and odors found
to be present when Chinese Drywall has been used during construction or
renovations.
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Step One - Odors:
Does the home, or certain rooms have either a sulfur-like odor or
other unusual odors? If there is a “rotten-egg” like odor or
“sewer-gas” smell, verify that they are not from the home’s water, or a
sewer problem. Sometimes sulfur odors can be noticed from water
heaters that have sat unused for a long time.
Step Two - Recurring and costly A/C problems:
Have there been repeated failures of the A/C evaporator coil
(located in the air handler unit)? This type of failure is due to a
black corrosion of the coil resulting in leakage of Freon from the
system, making it impossible to cool the home, requiring replacement of
the coil. Many of the effected homes have had to replace their AC coil
numerous times and the coils last two years or less instead of the
normal 10 to 20 years.
Step Three - Charcoal or black corrosion of copper Freon Lines:
A -
Look to see if the compressed Freon line into the air handler has a
black appearance, due to sulfur corrosion. This copper line is
approximately ¼ inch in diameter and can be easily viewed without
opening the air handling unit (AHU) or removing any panels. If the air
handler is in an interior closet or in the garage, go to it and look at
the un-insulated copper line going into the air handler. Compare it to
the images below. The image on the left shows the normal copper patina
caused by age and normal exposure to the environment. The image on the
right shows the blackening copper corrosion that is typically caused by
exposure to corrosive gasses.
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Normal Copper Patina
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Copper Corrosion due to Sulfur Emissions
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***IMPORTANT NOTE ***If your air handler is located in the attic or
in a crawlspace beneath the home, we recommend you have a state
licensed air conditioner contractor evaluate copper corrosion on the
coils inside the unit as described in Step 3A. It is less common to
find the blackened copper corrosion on the un-insulated Freon line when
the air handler is located in the attic or crawlspace.
--or--
B –
Corrosion of other metallic surfaces in the home:
If you cannot see your AHU’s compressed Freon Line, other signs
of metal corrosion may be observable. Look around the home for
corrosion on other copper and metal surfaces. Any exposed copper,
brass or metallic plumbing fixtures can sometimes exhibit signs of
sulfur corrosion. images on the right show corrosion on a cut off
valve and copper plumbing. images on the left shows normal copper
discoloration on copper plumbing lines.
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Normal
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Corroded
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Normal copper plumbing
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Corroded copper plumbing
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Normal shut off valve
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Corroded shut off valve
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Step 4 - Drywall made in China:
Identifying drywall made in China may be the most difficult and
possibly inconclusive. This requires cutting holes in walls to find
printed markings on the back side of drywall that says ‘Made in
China.’ Finding those markings are not guaranteed. Homes can have
drywall from multiple manufacturers, American and imported. Should you
have the odors described in step one and notice they are strongest in a
particular room of the house, you should consider hiring a building
inspector, contractor or other building professional look in that room
first. It is possible that the imported drywall was installed on the
ceiling. You can look under the insulation in your attic space for the
markings. . The pictures on the right show markings typically found on
drywall made in China. The images on the left show pictures of
American drywall markings. Some drywall has no marking at all.
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Domestic drywall with markings
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Imported drywall with markings
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Domestic drywall with "National Gypsum" markings
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Imported drywall with "China" markings
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Domestic drywall with "GridMarx" markings
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Imported drywall with "Knauf Tianjin" markings
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Imported ceiling drywall with "Knauf" markings
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Step 5 - Hire a professional inspector to confirm the presence of corrosion on Electrical Wiring or A/C Coils:
Accessing these areas pose an electrical shock hazard. Hire a
professional inspector or certified or licensed technician to check the
A/C coil and a licensed electrician to inspect electrical wiring for
distinctive corrosion. On the left is an example of what normal
oxidative A/C coil aging looks like. The copper shown here has the
red/brown/green patina typical to most homes. On the right is an
example of the black corrosion that is typical of a copper A/C coil
from a home experiencing this problem.
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Normal
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Corroded
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Normal oxidative A/C coil aging
Normal copper tubing
Normal copper tubing
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Black corrosion that is typical of a copper coil from a home experiencing problems
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You should hire a licensed electrician to inspect your home’s
electrical system. An inspection of the home’s electrical wiring should
reveal normal copper color on the un-insulated ground wires located in
the main breaker panel, in light switches, and in electrical outlets
around the home as depicted in the image on the left. Should the
electrician find black corrosion as seen in the image on the right,
that is a strong indicator of the corrosion often seen in homes with
Chinese drywall.
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Normal
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Corroded
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Normal wiring
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Black corrosion on wiring
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Normal outlet
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Black corrosion on wiring
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Step Six - Count the Number of “Yes” Answers
The home meets the Case Definition if it was built after January 1,
2004 and you answered “Yes” to two or more of the questions above.
If the home was built before January 1, 2004, and you answered
“Yes” to three or more of the questions, your home still meets the Case
Definition.
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