chinese drywall
chinese drywall
(OP)
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.
We have a commercial client who wants our advice.
Appreciate any comments.





RE: chinese drywall
Are you a registered engineer (forensic or similar)or an "ambulance chaser"?
More detailed, "uncloaked" information would give more responses and specific replies.
Dick
RE: chinese drywall
I understand. This is a big potential problem which has hit the media yet.
Yes, we are licensed as a professional engineer in the State Of Florida.
If you have access to this web site service, then you know they screen everyone.
Let me know how we can help.
But now we are looking for some registered engineers to give some advice on how to procede wih advising our client.
All the best.
Sam
RE: chinese drywall
China makes the most violins in the world, the cheapest (imported wood from the U.S. and Russia) and also the finest (from native native Chinese spruce), so anything is possible and shotgun approaches always scare me even if I make money testifying.
It all goes to the specific product, the importer/marketer and the specifications of the product. Documentation is critical.
If your commercial client is a developer/builder or drywall contractor, get what information was collected in the purchasing/installation process. If none is available, the only choice is to tear out areas to see if there is identification. Trying to test for the air quality in a completed structure will not provide any accurate information because there are many other factors.
There are always errors in manufacture/distribution, but usually the back of the sheet gives clues. Some people build by the unit cost or availability and do not care about anything else. Any product with no information is a "tip-off" to possible intention to remain unidentified. Certainly builders do not do much testing or verification except for the rash of problems with buildings built during the lack of availability a few years ago.
Good luck.
Dick
RE: chinese drywall
http://www.cpsc.gov/info/drywall/jul2009status.pdf
RE: chinese drywall
An example...I recently read a report by an IAQ "expert". He indicated that they had the drywall analyzed and found copious sulfur/sulfates. Well imagine that! Gypsum is calcium sulfate. One astute consultant stated that looking for sulfur in drywall is like looking for hay in a haystack!
There are no established criteria for chemistry. There are no protocols for testing. There are no objective methods of establishing criteria for rejection....the only thing we can do definitively at this point is look at the labeling on the drywall and see if it comes from China.
There might be some true issues with the drywall. If sufficient sulfides are given off as a result of the drywall, then some of the common manifestations are practical...blackened copper wiring, corrosion of metal features, damage to HVAC systems, and irritation to human sensitivity. There are other things that can cause these as well.
For instance, in Florida, it is common to find H2S in the water. In some cases, it is very high. I have seen corrosion of piping and peripheral items resulting from the "sulfur water" in Florida. This has to be ruled out as a cause before blaming the drywall.
Lots more unknowns currently with "chinese drywall" than knowns. Need to establish investigation protocols, chemical testing, physical exposure testing and air testing.
RE: chinese drywall
Dik
RE: chinese drywall
i am a florida PE. this has been in the media here for over a year now...
RE: chinese drywall
htt
RE: chinese drywall
RE: chinese drywall
Thanks to all who took the time to respond.
This is the reason we support eng-tips.com.
One of the briefings we recently attended was a presentation of a testing device developed by DRYWALL SCIENCE, LLC, by Jack M Frost who is located in Ft. Myers, Florida.
There must be others who are working on this problem.
Appreciate any comments, good or bad.
Sam
RE: chinese drywall
a) as far as indoor air quality goes , and its relation to consumer health and corrosion of copper alloys- perhaps the least costly fix is to install air recuperators ( air to air heat exchanger) with a large flow of fresh outdoor air to ensure the concentration of H2SO3 is below some allowable limit. The problem may be exacerbated by tightly sealed homes.
b) US style wallboard plants utilize clean natural gas to dry the wet gypsum boards, but this would be a very costly option in China which has limtied supplies of nat gas . Instead, I think the problem may be associated with the chinese use of coal fired plant hot fluegas to dry the wet gypsum boards, and this flue gas has high, unscrubbed levels of SO3 in it.
RE: chinese drywall
Did you get the answers you were looking for?
I've been monitoring the remediation throughout S. W. Florida for nearly 6 months now.
Mike
RE: chinese drywall
RE: chinese drywall
I work for one of the companies gathering samples and evidence for litigation. As well as standing behind demo crews documenting the drywall removal.
Homes are torn down to the studs. Only thing not removed is the exterior walls, roof and tiled flooring.
It's a mess!
Mike
RE: chinese drywall
RE: chinese drywall
Up front, some of the home builders are footing the bills.
That is those who are still around or haven't re-organized into another name to protect themselves. But I only hear rumors of that.
Some homeowners (very few I suspect) are spending their own money to get it done.
RE: chinese drywall
RE: chinese drywall
The builders, as I said previously, mainly the large volume builders are trying to be a little pro-active about it and take care of it themselves.
If the homeowner can not find the builder or does not want to work with the builder, they get a lawyer.
And your right, a lawyer may want to go after everyone who had any part of importing Chinese drywall. The thing is, even the lawyers have few choices to pursue.
A lot of the suppliers have closed their doors due to the building bust and the importers have pretty much disappeared. So their only recourse is to try to pressure the builder and the Chinese companies and exporters themselves. Good luck with that.
I think they have a few other avenues they can follow but each is costly.
Class actions suits due occur, I've read, but it is mostly against the builder in a community to try to force them into remedying the situation.
There is a federal judge who has been assigned to this case in New Orleans. He will preside over all Chinese drywall cases in the US. Here is a link to a pre-trial order: htt
RE: chinese drywall
It is well known that hydrogen sulfide gas may be produced when landfilling or using gypsum as alternate daily landfill cover, particularly in a wet climate. Several conditions are required, including a moist, anaerobic environment and a low pH. Hydrogen sulfide gas is toxic at high concentrations (~1,000 parts per million) and has a foul, rotten-egg odor.
H2S is a weak acid, donating two hydrogen ions in neutralization reactions, forming HS- and S-2 ions. In water, the three sulfide species, H2S and HS- and S-2 ions, are in dynamic equilibrium with water and H+ and OH- ions. The percent distribution among the three sulfide species depends on pH. H2S is dominant at low pH, the HS- ion is dominant at mid-range pH and S2 ions dominate at high pH. In this equilibrium situation, sulfide ions revert to H2S if the pH falls.
In water, sulfide can exist in three forms; hydrogen sulfide (H2S), bisulfide (HS-), and sulfide S-2. The sulfide species present is dictated by the pH. At pH values less than 6, hydrogen sulfide (H2S) dominates.
RE: chinese drywall
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
RE: chinese drywall
Mike
RE: chinese drywall
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:
h
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.
http://www.cpsc.gov/info/drywall/TabA.pdf
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.
http://ww
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.
http://www.abbrclaw.com/en/press_releases/
RE: chinese drywall
RE: chinese drywall
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
RE: chinese drywall
Excellent analysis.
Sam
RE: chinese drywall
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.
RE: chinese drywall
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.
RE: chinese drywall
RE: chinese drywall
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.
RE: chinese drywall
CDG, Civil Engineering specializing in Hillside Grading in the Los Angeles area
http://www.CivilDevelopmentGroup.com
RE: chinese drywall
RE: chinese drywall
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:
h
RE: chinese drywall
Water intrusion from the exterior finish will exacerbate the issues.
RE: chinese drywall
CDG, Civil Engineering specializing in Hillside Grading in the Los Angeles area
http://www.CivilDevelopmentGroup.com
RE: chinese drywall
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.
RE: chinese drywall
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