Problem Overview: “The issue of toxic Chinese drywall may well become the biggest environmental crisis to hit North American homeowners and builders in decades.”
Who is affected?
Hundreds of millions of sheets of the defective drywall were imported into the United States between 2001 and 2007. It has been reported in as many as 14 states, and may have been used in an estimated 100,000 renovated and newly-built homes, with up to 40,000 in Florida alone.
In addition, an estimated 929,000 square metres arrived in Canada through Vancouver in the same period.
Much of the product imported into Canada was used in the lower B.C. mainland, but some may have reached the Prairies and as far east as Toronto (Source)
Does this pose a health hazard?
The Toronto Star article (sourced above) reports: “The defective Chinese drywall emits toxic hydrogen sulphide, sulphur dioxide and other gases. It is believed that humidity in the air causes the sulphur in the drywall to off-gas, or migrate into the indoor air. This creates a noxious odour, and can result in serious health conditions and illnesses, such as breathing problems, eye irritation, fatigue, dizziness, insomnia, sore throat, bloody nose, and headaches.”
Houses built or renovated with contaminated Chinese drywall cannot be repaired. The only possible fix for affected homes is to have the owners move out for several months, gut the house and rebuild the interior. Anything inside the house that may have been contaminated by the sulphur gases will also have to be destroyed and replaced.
Industry watchers have estimated that as few as three sheets of drywall in a house can be enough to contaminate it to the point of making it uninhabitable – Toronto Star
Florida’s Division of Environment Health has put together this self-assessment guide.
1) 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.
2) 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.
3) Corrossion of 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.
Corroded Shut-off Valve
Normal Shut-off Valve
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 below are markings typically found on drywall made in China
Made in China
Imported drywall with "Knauf Tianjin" markings
5) Hire a professional inspector to confirm the presence of corrosion on Electrical Wiring or A/C Coils 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 below, that is a strong indicator of the corrosion often seen in homes with Chinese drywall.
I contacted one home inspector and they’ve said they’ve been on the lookout for it in Calgary for a few months but haven’t seen any Chinese drywall yet. CREB will be monitoring the issue as well.
Chinese Drywall Under Study in US – CBC News, June 3, 2009
Chinese Drywall Creating Crisis, Toronto Star, June 20, 2009
Drywall has China Defensive, Herald Tribune, April 25, 2009
US Senators Call For Chinese Drywall Probe, Asia Times, June 24, 2009
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