Chinese Drywall: Years, Signs and How to Identify It

Short answer: “Chinese drywall” is the common name for problem drywall, much of it imported from China, that was installed mainly in homes built or renovated from 2001 to 2009. CPSC has received about 4,051 reports, most from Florida, with owners describing blackened copper wiring and air conditioner coils; CPSC and HUD’s identification method starts with that corrosion plus the installation years.

Check a specific house: problem drywall is rated medium for homes built in 2006 and 2007 and low for 2001 to 2009. Open the House Age Decoder with 2006 loaded →

What “Chinese drywall” means

Drywall (also called gypsum board or wallboard) is the standard interior wall material in American homes. In the mid-2000s, homeowners began reporting that some drywall in their houses seemed to be corroding metal and, they believed, causing health symptoms. Federal agencies call it problem drywall.

The nickname comes from where much of it was made. CPSC’s reports concern drywall produced in China. But CPSC’s own identification guidance is careful on this point: Chinese markings on a board are only one piece of supporting evidence, because not all Chinese drywall is problem drywall and markings can be missing or hard to see.

Which homes are most likely to have it

Factor	What CPSC reports	Source
Build year	Owners largely report homes built in 2006 to 2007	CPSC
Installation window	The identification method looks at drywall installed 2001 to 2009	CPSC
Location	The majority of reports come from Florida; reports also came from many other states, DC, American Samoa and Puerto Rico	CPSC
Volume	About 4,051 reports from residents of 44 states, DC, American Samoa and Puerto Rico	CPSC
First report	December 22, 2008	CPSC

CPSC ties the timing to a period of unprecedented new construction, driven partly by the 2004 and 2005 hurricanes. That is why homes built or rebuilt in those years, especially in hurricane-affected areas, come up most often. A house built earlier can still be affected if it was repaired or remodeled during that window.

Signs to look for

The most common sign is not on the drywall at all. It is on metal in the house. Homeowners have reported corrosion or blackening of metal in or on electrical fixtures, appliances, plumbing and air conditioner coils.

Things an inspector or HVAC technician may notice:

Blackened copper on ground wires visible at outlets or switches (seen by a professional with the cover removed).
Blackened air conditioner evaporator coils, sometimes with a history of repeated coil failures.
Corroded metal on plumbing fixtures or appliance parts that seems out of proportion to the age of the house.
Markings on the back of drywall boards, visible in an attic, garage or behind an access panel.

Do not open electrical boxes or remove fixtures yourself to look. This site does not give instructions for electrical work; that is a job for a licensed electrician.

How CPSC and HUD say to identify it

CPSC’s guidance uses two steps.

Step one: threshold conditions. A visual inspection must find both:

Blackened copper electrical wiring and/or blackened air conditioner evaporator coils.
Drywall installed between 2001 and 2009.

Step two: corroborating evidence. If both are present, look for supporting markers. Homes with drywall installed from 2005 to 2009 need at least two; homes with drywall installed from 2001 to 2004 need at least four. The markers include:

Elemental sulfur in the drywall core (lab test).
Copper sulfide on test coupons, ground wires or AC coils (lab test).
Chinese markings on the drywall.
Elevated sulfide gas emissions from the drywall (lab test).
Corrosion caused by the drywall in test chambers (lab test).

Most of these markers require laboratory work, so identification is a job for qualified investigators, not a quick visual check. CPSC also notes that other causes can produce similar corrosion, so the source should be confirmed for each house.

What the remediation guidance covers

CPSC and HUD staff published remediation guidance, current as of March 15, 2013. For homes identified under the joint method, it calls for replacing:

All possible problem drywall (drywall known to predate 2001 with no other warning signs may stay).
Smoke alarms and carbon monoxide alarms.
Electrical distribution components such as receptacles, switches and circuit breakers. Wiring is not necessarily replaced.
Fusible-type fire sprinkler heads.

The guidance also says gas service piping should be inspected and pressure-tested under the applicable fuel gas codes, and glass-bulb sprinkler heads tested or replaced under NFPA standards. Every item on that list is work for licensed contractors, electricians and plumbers working under local permits.

Questions to ask

The home inspector

Do you see blackening on any visible copper, such as ground wires or AC coil lines?
Is there any visible marking on the back of drywall in the attic or garage?
Would you recommend an evaluation by a qualified investigator using the CPSC/HUD method?

The seller

When was the drywall installed, and was any replaced after a storm or remodel?
Has the AC evaporator coil been replaced? How many times, and why?
Has the house ever been evaluated or remediated for problem drywall? Can I see the report and the contractor’s paperwork?

Your HVAC contractor

Does the evaporator coil show unusual blackening or corrosion for its age?
Is the coil original, and what is its repair history?

Your insurance company

Do you ask about problem drywall when writing a policy for homes from this period?
Would corrosion damage from drywall be covered or excluded under this policy?
Will you want documentation of any past remediation?

What to do if you suspect it

Get a professional evaluation that follows the CPSC/HUD identification guidance before drawing conclusions.
Collect records: build date, drywall installation dates, repair history and any past reports.
Do not open walls or electrical components yourself.
If remediation is needed, work with licensed contractors and follow the published guidance and local codes.
Talk to your health provider if you have health concerns you think may be related to your home.

This guide does not offer legal advice. For questions about past claims or disclosure duties, speak with a licensed attorney in your state.

Common misunderstandings

“It’s Chinese drywall, so it’s bad.” Not all drywall made in China is problem drywall. CPSC treats markings as supporting evidence only.
“No markings means no problem.” Markings may be absent or hard to see.
“It only affects Florida.” Florida has the most reports, but reports came from dozens of states.
“It’s only in brand-new houses.” Older homes repaired or remodeled during the 2001 to 2009 window can be affected too.

Quick answers

Is all drywall from the 2000s a problem?

No. The decoder rates it medium only for 2006 and 2007 builds.

Can a home inspector confirm it?

An inspector can spot warning signs, but confirmation under CPSC’s method usually needs laboratory testing by qualified investigators.

Is the problem still ongoing?

CPSC says it has completed its investigation and points consumers to its identification and remediation guidance.

Before-you-buy checklist

Ask when the drywall was installed and whether any was replaced after 2000.
Ask about AC coil replacement history.
Have the inspector look for blackened copper and drywall markings where visible.
Request any prior evaluation or remediation reports.
Check what else is typical for the build year with the House Age Decoder.

Chinese Drywall: Years, Warning Signs and How It Is Identified