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		Copper Corrosion due to Sulfur Emissions

***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		Corroded
Normal copper plumbing		Corroded copper plumbing
Normal shut off valve		Corroded shut off valve

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		Imported drywall with markings
Domestic drywall with "National Gypsum" markings		Imported drywall with "China" markings
Domestic drywall with "GridMarx" markings		Imported drywall with "Knauf Tianjin" markings
		Imported ceiling drywall with "Knauf" markings

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			Corroded
Normal oxidative A/C coil aging Normal copper tubing Normal copper tubing			Black corrosion that is typical of a copper coil from a home experiencing problems

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		Corroded
Normal wiring		Black corrosion on wiring
Normal outlet		Black corrosion on wiring

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.

                                         Humberto Carvajal   Jr.

A Florida Inspection Company

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A Florida Inspection Company
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