Corrosive or Chinese Drywall


Call Tom at 4D Building Solutions at 813-300-5027

Knaupf Drywall

Chinese or Corrosive drywall just doesn’t go away!  Every day we see more and more instances of it in homes primarily built between 2004 and 2007.  In Florida, it has been found in homes built as early as 2001 and as late as 2008.  Any home built during this time frame must be carefully analyzed for the visual evidence so as not to be surprised later on with some bad news.  The CPSC and the State of Florida state that the best means of determining the presence of Corrosive Drywall is through a thorough visual inspection conducted by someone knowledgeable and experienced in finding this material.  Keep in mind that there are no officially recognized or established qualifications or designations for a Corrosive Drywall Inspector.  Any “designations” currently out there have generally been created by the company that provides the training.

There is no test which will enable an inspector to visit a home and conclusively determine the presence or absence of Chinese or Corrosive drywall.  Beware of those who say that there is.  The use of XRF or FITR technology cannot in and of itself make that determination as it is checking for the presence of the element strontium.  It has been determined that the presence of Strontium is NOT a marker for corrosive drywall.  XRF and FITR are great methods for making different determinations, and have a useful place in some corrosive drywall investigations.   The only recognized method of confirming whether a piece of drywall is corrosive is to have the sample analyzed by a qualified Laboratory for the presence of Elemental sulfur (Orthorhombic sulfur, cyclooctasulfur, S8).

The best course of action for confirmation is to hire an independent company or inspector familiar with the process to conduct a thorough visual inspection of the property providing photo documentation of all conditions present which would indicate the conditions associated with corrosive drywall.  Samples should be taken from various locations throughout the property and properly documented with a chain of custody.  The samples should be sent off to a third party lab for analysis for elemental sulfur.  The threshold that has been established for elemental sulfur content is 10 mg/kg.  Anything over this number is considered to be corrosive.Made in China Drywall

Some of the myths of Chinese drywall:

  • it always has a strong odor
  • it is never installed in ceilings
  • All chinese drywall is bad
  • All U.S. drywall is good
  • There are simple ways of remediating a home with corrosive drywall
  • You don’t have to remove all the drywall from a home if it was not made in China
  • Strontium is a good marker for determining the country of origin
  • The use of XRF technology will confirm the presence of corrosive drywall
  • There is no test for Chinese drywall

C&K Drywall

Since early 2009 I have been involved with numerous cases involving corrosive drywall.  The one thing that I have come to realize is that whatever “truths” we believe about corrosive drywall will probably be thrown out at some point.

If you have questions about corrosive drywall and what options are available for determining the presence please give me a call or drop me an email to Tom@inspectorhelp.com

Here are some conversations that I have had about Corrosive Drywall:

About Remediation:
Q:  Hi Tom, I am looking at chinese drywall Homes in Florida, I understand I would need to replace all the drywall but  what about the wiring.  Can’t I just clean and reconnect with new outlets.  I assume the insulated part of the wire is unharmed from the corrosive gas and how about the wood structure do I need to treat it or any thing?
Thanks, Mike

A:  The current NAHB and CPSC guidance recommends a partial remediation.  This is removal of only the bad drywall leaving the good.  Safety items such as smoke detectors should be replaced.   Everything else should be evaluated by qualified contractors to determine whether to replace or not.  Most wiring probably would not need to be replaced.  Wood components do not need to be treated although some have sprayed with a biocide just for good measure.  The wood needs to air out for a few weeks before new drywall is put back on.

Every house is different depending on how bad and how extensive the corrosive drywall is.
Q:  I bought a house with chinese drywall, we removed all the drywall but I need to know if we need to also remove the blow in insulation as well? Is it contaminated too?
 Any help with this would be greatly appreciated!
 Many Thanks,
 Misty

A:  Misty,

As you have probably already discovered, this is a controversial subject.  Judge Fallon’s protocol calls for removing everything!  On the other hand, the CPSC and HUD recommend a partial remediation.  Which one you follow seems to boil down to a personal decision, as the real science behind both of the methods is a bit vague.  There are so many variables as to what could be cross contaminated and how.  Factors such as the manufacturer of the drywall and how much elemental sulfur was present in the samples will certainly affect it.  As far as whether to replace blown in insulation, let’s break it down this way… The blown in insulation is supported by the ceiling drywall.  If the ceiling drywall is removed, the insulation comes down!  Personally I don’t think trying to salvage that stuff would be practical.  If the ceiling drywall was not identified as corrosive and left in place, then it created somewhat of a barrier and the insulation shouldn’t be affected.  In general terms, most insulation doesn’t really have the ability to trap the off gassed material and hold on to it anyway.  In the overall scheme of the remediation, insulation should not be a major cost factor.  The effort taken to preserve it is probably not worth it.  Keep in mind that from an energy standpoint, insulation installation is critical.  Much of it’s insulating effectiveness may be lost or compromised by the demolition and reconstruction.
In my opinion, you need to identify all of the good and the bad drywall.  Remove the bad drywall.  Have a professional such as an electrician examine the electrical system and have the other house components which can affected by corrosive drywall checked out also.  Then the decision can be made on a case by case basis for what has to be removed.
One of the big questions you have to consider, is that if you go to sell the property somewhere down the road, can you adequately demonstrate that the bad stuff, whatever it is was, was removed.  Photos, videos, lab results showing sampling results and visual inspection results from experts should be maintained as the documentation you will need to pass down.