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chinese drywall 13

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smwpe

smwpe

Structural
Aug 20, 2003
70
You may not be involved in this problem but it will attract some attention soon. If your firm does work in Forida then my advice is to be careful. This is not a simple lead based paint problem. To give you a perspective, the leading engineering university in florida recently conducted a seminar where the speaker was -----.

We have a commercial client who wants our advice.

Appreciate any comments.
 
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bestmd Mike:

Thank you for your insight. Maybe after all this is a mechanical engineering problem.

Thanks to all for your response.

I will keep you informed of how we are managing this problem with our clients.

Sam
 
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Sam, send me a contact number or company name. I'll be in Fort Myers on Monday then back up to Tampa for a few days.

Mike
 
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This is not a mechanical engineering problem. It is a product liability problem.

In hot and wet environments, chinese made drywall may off gas into hydrogen sulfide, carbon disulfide, and carbonyl sulfide and contaminate a structure’s air supply.

The first step is to determine if you have a problem. Analytical testing laboratories have now come up with a low cost ($100) test method to determine if you have problem drywall:


When CPSC tested drywall, all but one of the Chinese drywall samples had detectible levels of elemental sulfur. No U.S. made drywall samples had detectible levels of elemental sulfur.


The Florida Department of Health removeed drywall from structures that were constructed with drywall from three Chinese manufacturers and published the findings. They found “a distinct difference in drywall that was manufactured in the United States and those that were manufactured in China.” The Chinese samples contained traces of strontium sulfide and emitted a sulfur odor when exposed to moisture and intense heat, while the American made samples did not.


Most of the drywall problems are reported in Florida and other southern states, likely due to the high levels of heat and humidity in that region. Most of the affected homes were built during the housing boom between 2004 and 2007, especially in the wake of Hurricane Katrina when domestic building materials were in short supply. An estimated 250,000 tons of drywall were imported from China during that time period because it was cheap and plentiful.

A home inspection can use the following tips to identify if a structure is contaminated:

The house has a strong sulfur smell reminiscent of rotten eggs.

Exposed copper wiring appears dark and corroded. Silver jewelry and silverware can become similarly corroded and discolored after several months of exposure.

A manufacturer’s label on the back of the drywall can be used to link it with manufacturers that are known to have used contaminated materials. One way to look for this is to enter the attic and remove some of the insulation.

Contaminated drywall cannot be repaired. The drywall must be replaced entirely, a procedure which can cost tens of thousands of dollars. Some insurance companies are refusing to pay for drywall replacement. Class-action lawsuits have been filed against homebuilders, suppliers, and importers of contaminated Chinese drywall. Some large manufacturers named in these lawsuits are Knauf Plasterboard Tianjin, Knauf Gips, and Taishan Gypsum.

Like all product liability cases, the lawyers will flock to sue those with the deepest pockets. The lawsuits will drag on for years, the lawyers will then retain a large share of the recovered funds, and in the end, the injured will probably receive a small fraction of their claims.

 
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How sad. Consumer protection becomes a tool to en-rich the lawyers. But without them, there won't be justice done.
 
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bimr, all good comments from other sites, but being a "grunt" in the field there is no defined science to any of it.

As pointed out by Ron earlier in this thread, all US based drywall does contain a very small amount of sulfur in the gypsum. The percentage between the US brands and the Chinese brands is in a high double digit percentile though.

One misconception during inspection is that you can determine which brand is in the house by looking in the ceiling for a label is a waste of time. In all the homes I've visited, less than 5% had Chinese drywall in the ceilings.

Exposed wiring, facets, silverware, pennies, any copper and mirrors will show signs of pitting or turning black over a period of time.

The initial smell or scent in some homes gives it away when you walk into an enclose home. The longer we are in the home our senses adjust to the surroundings and we don't notice it as much. That is, until you open a wall and the gas just blasts you in the face.

Other than demoing a house of drywall there are 2 other types of testing going to rid a home of the S2O. One uses a charcoal filtering system mounted before the air exchanger to filter the gases. It does not rid the home of the problem but removes the smells and irritants from the house. I think I read somewhere the estimated cost of maintenance to the system is around $60/month.

The second attempt to rid the home of S2O is by placing a large sealed bubble over the home then flooding it with Chlorine Dioxide (I think). This method is supposed to cause the sulfur gases to become inert. I believe this process is still in a testing stage and costs between $30K-$50K per house.

I think both of the mentioned systems are being sold but on a test basis so far. I have not run into either process and have no knowledge their current use or plans.

Liability, environmental, mechanical and chemical; it will take all of these things to put together a sensible solution to repair what was done.

The builders are no more at fault than we are as consumers when we go to WalMart to buy things we need everyday. Nearly everything we own came from somewhere else. And that boils down to supply and demand. Which is delegated by price.

During the building boom and after the hurricanes in 2005, drywall demand was at an all time high. The building of homes and the rebuilding of homes drove the drywall prices up and the supply was strained. Drywall was shipped in from China, Mexico, Brazil and Germany to support the US demand. The only requirement for US drywall at that time was that it meet ASTM C1396 standard. There was no need to do a chemical test of the material it had to be built to a structural standard.

Gypsum is gypsum right? Well after 3 years we now know that there must be environmental/chemical testing as well.

As I said in my first post, what a mess!

Mike

 
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bestmd Mike:

Excellent analysis.

Sam

 
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bestmd...I didn't say that all US based drywall has a small amount of sulfur. One the contrary, calcium sulfate dihydrate (the form of gypsum used in drywall) contains quite a lot of elemental sulfur (somewhere around 5 to 8 percent in the dihydrate form, and upwards of 18 percent in the unhydrated calcium sulfate).

I've seen test results from other consultants who have found 350 ppm of sulfur in drywall samples, alluding that the amount was inordinately high. 350 ppm is way less than 1 percent.

My point is that there are other mechanisms working here rather than just looking at sulfur. It is perhaps one constituent of the problematic exposure, but by no means can one determine that the culprit is drywall by testing only for sulfur.

I'll reiterate that there needs to be some concerted effort and discussion to develop responsive, repeatable test procedures to determine the actual cause of the formation of H2S and other sulfides as off-gassing constituents of drywall.
 
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Regardless, during part of the initial testing, sulfur content as well as a couple other methods have been extremely reliable for us to determine prior to demo stage whether a house contains Chinese drywall or not.

So yes, there are other means of testing than relying on just a sulfur test.

I have yet to tear a house down where the testing was wrong and Chinese drywall was not present in the house.
 
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Rotten eggs smells ... you need a H2S detector (oil & gas industry)
 
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bestmd...and based on your comments, there is a high likelihood that you've removed a lot more drywall than was necessary, resulting in additional cost to someone and inconvenience to others.

There's no question that the problems can be real and the impact significant. I'm just not a proponent of voodoo science to achieve a preconceived result.
 
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Does anyone know why this happened in certain building boom areas but not in others? I am surprised to not hear about this problem in the Southern California main boom area.

CDG, Civil Engineering specializing in Hillside Grading in the Los Angeles area
 
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It hasn't shown up because the humidity is not high?
 
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Don't make this more complicated that what it is. The only testing that needs to be done is a test for Strontium Sulfide.

Strontium sulfide (SSr) and gypsum (calcium Sulfate CaSO4) are two different chemical compounds and each chemical has different chemical properties.

For example:
....STRONTIUM SULFIDE

.....General Description
.....PHYSICAL DESCRIPTION: Gray powder with an odor of .H2S in moist air.

.....Air & Water Reactions
.....Slowly releases H2S in moist air.

That should be a big clue - "odor of H2S in moist air". "Slowly releases H2S in moist air"

The sulfur in gypsum is not a problem because it is fixed. To change the sulfur in gypsum (sulfate to sulfide, a chemical reduction reaction has to happen. Reduction is the decrease in oxidation state by a molecule, atom or ion. The change in state would be from SO4 to S-. In environmental chemistry, that reduction reaction typically occurs with an anaerobic process.

However, sulfate reduction will not happen in a house. An anaerobic process will not take place in a house because there is plenty of oxygen. So the sulfate sulfur is fixed in drywall.

You do not need to analyze for sulfur. If you analyzed for total sulfur, you would pick up the sulfate. You need to analyze for sulfide.

New article about hydrogen sulfide was just published in Scientific American:

 
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bimr...exactly! Analyzing for sulfur is a waste of time. Look for specific compounds that can occur and react.

Water intrusion from the exterior finish will exacerbate the issues.
 
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No voodoo science with preconceived results? I mentioned we have a couple of other methods to test between domestic and other brands.

All homes encountered contained Chinese drywall. The AC coils and wiring showed advanced corrosion indicative of the bad drywall.

The resulting removal of the drywall was necessary. No additional costs or inconvenience were incurred based off visual evidence during removal.

"Science" has been working on trying to come up with a viable solution to this problem for almost 2 years. Reality is to remove it.

If you live in one of these homes, you want it gone and you want assurance to make sure it is gone. The only way to do that is to remove it all.

I added comments to point out what is being done to a certain extent. Now I'm being accused of costing money and time. Unless anyone else is directly involved in this mess and has a better solution, the accusations are without merit and inappropriate.
 
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I don't know all the science involved here, but if I were to buy a used house built since 1999 in Florida I would require a certification by bestmd that there is no Chinese drywall in the house.

Thanks again to all who responded to this thread.

Sam
 
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