Inspections, Documentation and Consultation from Leading Experts



If you think you have Chinese Drywall, experience matters!  Chinese Drywall Screening, LLC,  is a professional engineering firm with one of the most experienced team of inspectors and consultants in the country covering Florida and the Southeast.  Since 2009, our team of inspectors have inspected more than 3,000 homes and commercial properties with over a 1,000 cases filed in legal proceedings dealing with the corrosive Chinese drywall.   CDS, LLC has been at the forefront of this evolving issue since the very beginning and has been inspecting properties and helping owners for ten years.   

Howard Ehrsam, P.E. is the Principal and founder that been involved in all aspects of design and development for over 25 years.  He utilizes his extensive experience to provide the best and most valuable advice for every unique situation.


When you entrust our team to inspect your property you can expect top quality service and exceptional customer care. Our inspection protocols include: 

  • Visual inspection along with drywall label identification
  • X-ray Fluorescence (XRF) for strontium to non-destructively identify the different manufactures
  • Drywall sample testing
  • Environmental Corrosion Testing

For a standard inspection, it is critical to use visual and XRF to make accurate conclusions to avoid false positives that can be create havoc for real estate transactions.  

Our protocol is well established and is the best method for accurate determination and reporting. We provide a detailed report and a photographic record of the inspection and its results.  This detailed documentation is critical for dealing with lenders, insurance companies, builders, and attorneys. There are many false positives and false negatives with various inspection techniques. It's critical to have a comprehensive understanding of Chinese and corrosive drywall as well as a thorough inspection and testing techniques in order to properly draw accurate conclusions.


If we do find corrosive Chinese drywall, we can help develop a strategy with you to help resolve this issue.  Additional services include: 

  • Mapping the locations of the corrosive drywall
  • Preservation of Evidence 
  • Post-Remediation Verification 

We will be your advocate.  Regardless of your situation, we have experienced it personally and/or professionally and will help you every step of the way.  


Was your property built or renovated between 2001-2008?

During these years, the corrosive Chinese drywall (CDW) was used to build and renovate tens of thousands of residential and commercial properties

Do you notice a certain smell or odor?

Corrosive Chinese drywall sometimes gives off a distinct odor.  The severity of the odor can depend on which brand of corrosive Chinese drywall you may have in your property.  

Have you had to replace your A/C coils?

Copper A/C coils are one of the first areas to check if you think you have corrosive drywall. The coils can have a blackened residue.  The severity of the blackening will depend on how much and what type of  CDW is in the property. You may also see this type of blackening on your electrical wires.

Are your faucets corroding or have black spots?

CDW can also corrode faucets and other plumbing trim.  It may also desilver the edges of mirrors or cause a halo effect. 

Have you noticed blackening on your copper plumbing lines?

Just like the A/C coils, copper plumbing components and water lines are also susceptible to the corrosion caused by CDW.

If you answered yes, then you may have Chinese drywall.

While other factors can also cause similiar issues, our Chinese Drywall Screening's experts can determine if the issues are being caused by corrosive CDW using our proven testing protocol. 


Chinese Drywall Screening, LLC (CDS) will conduct a detailed visual inspection of the various elements that typically react to the presence of reactive drywall.  Some known affects are blackening copper, tarnishing silver, corroding and spotting chrome and brass, and delaminating mirrors.  The CDS inspector will complete a thorough inspection of these elements including,  but are not limited to: air conditioning components; copper plumbing lines; mirrors; electrical wiring; plumbing fixtures and trim.

Some of the above elements will be photographed during the inspection and will be included in the report.  Items that may be affected by reactive drywall but typically not inspected by CDS include, but are not limited to: Appliances; Smoke detectors; Fire sprinkler heads; Doorbells; Televisions; Security systems; Audio/video equipment; Control wiring; Silver jewelry; Brass instruments; Personal possessions; Thermostats. 

As part of the inspection, CDS will research property records for evidence of prior remediation.  Remediations require permits.  Although limited, the permit and inspection history can provide information of any potential remediation.  CDS looks for evidence of remediation or fraud during the inspection.

 X-ray Fluorescence (XRF) is used to test Strontium levels in the drywall.  XRF analyzers are handheld instruments used predominantly to evaluate the presence of metal constituents in building materials or other products.  XRF works by exposing a material to high energy x-rays and measuring those x-rays and comparing them to the known and unique pattern of x-rays produced by each element.  For help in identifying corrosive drywall, XRF is used to determine levels of strontium (Sr) present within the gypsum of the drywall throughout the property. 

Strontium is a light metal that is a common, naturally occurring element found within the earth.  Certain geographical regions have higher concentrations than others that can translate to the origin of the raw materials.  Strontium levels above 1850 ppm have been associated with drywall of Chinese origin.  However, high levels of strontium do exist in drywall from other origins and testing must be used in conjunction with other means to produce proper conclusions.

Sulfur Corrosion Testing of Drywall Samples
Our internally developed method of sulfur corrosion testing specific samples of drywall is to analyze copper and/or silver coupons for deposited sulfur utilizing x-ray fluorescence.  The sulfur is a byproduct of the corrosion of the metals from emitted sulfide gases.  Problematic or corrosive drywall emits sulfide gases that react with copper and silver to form copper sulfide and silver sulfide respectively on the surface of test coupons.  This process can be accelerated by elevating the temperature.

X-ray fluorescence (XRF) is utilized to quantify the sulfur deposits on the coupons in ug/cm2 (micrograms per square centimeter).  Readings can then be interpreted to determine to whether the drywall tested is corrosive and at what proportionate levels.  A non-detect (ND) reading upon analyzing the test coupons indicates there are no detectable sulfur deposits on the surface of the coupons.   This in turn leads to the conclusion that the drywall is non-corrosive at any significant or detectable levels during the course of the testing period.   Positive readings for sulfur are compared against various controls and known samples in order to make proper determinations as to the conditions of the samples being tested.  Samples with low levels of off gassing may need multiple rounds of testing to verify that the gypsum is the root source of the corrosive gases and the sulfur deposition is not a result from de-absorbed environmental sources. 



  • Overview of your situation
  • Complete summary and findings of the items/areas inspected
  • Photograph documentation of the inspection
  • List of potential follow up action items
  • Resources and reference materials.



Mapping is a very detailed process where the inspector analyzes every wall of the property to determine which walls/ ceilings need to be removed and cleaned of all drywall, dust and debris.  This service is critical if you are preparing to remediate the property.   The walls will be marked with permanent marker alerting the contractor which walls/ceilings/areas must be removed and the areas behind thoroughly cleaned.  Here is a video walkthrough of a property with domestic, corrosive Chinese and non-corrosive Chinese drywall:


There are numerous class action lawsuits that have been filed against the Chinese manufacturers of the corrosive drywall.  Make sure you contact an attorney to learn your legal rights and options.  In most cases, the drywall labels indicating the brand of corrosive drywall must be documented and the evidence must be preserved.  If you have reactive drywall and plan to remediate, sell or even walk away from a home in foreclosure, it is absolutely critical to consult an attorney and take steps to preserve evidence to protect any future claims before taking any action


Preserving evidence is needed to protect your interests if you are pursing any type of legal action.   The Pre-Trial Order No. 1(I) through the United States District Court Eastern District of Louisiana must be strictly followed.  Having an independent third party professional properly preserving your evidence is critical.  If this is not performed or done correctly, you could jeopardize the evidence.  The manufacturers and suppliers may claim the evidence was damaged and avoid compensating your for your losses. 

CDS, LLC will obtain, document and store (if needed) the evidence per the pre-trial order on your behalf.


This is probably one of the smartest steps you can take if you are planning to remediate a property with corrosive Chinese drywall.  CDS works for the owner, providing an independent, 3rd party inspection by a licensed engineer that includes detailed documentation verifying that properties are free and clear from reactive or corrosive drywall.  

Our company does a complete inspection BEFORE the new drywall is replaced to ensure the all the corrosive drywall, dust, and debris were properly removed.  If the drywall was not removed properly, CDS will instruct the contractor on what is deficient and make sure corrections are made.  Once everything is completed you will receive an Environmental Certificate signed and sealed by a licensed Professional Engineer.    This documentation is critical if you ever plan to sell or refinance the property.   


Another option is Environmental Corrosion Testing (ECT).  With this sevice several ECT devices are set inside the main areas of the property and fan(s) are utilized to circulate the air to ensure there were no stagnant pockets of air.  The property must remain vacant and can not be entered during the entire testing process.  The testing is seven (7) days.  Various measures were taken to prevent other potential sources of sulfide gases interfering with the testing.  Other potential sources include sewer gases, gas burning appliances, kerosene heaters, wood or coal stoves, tobacco smoke, malfunctioning chimney’s and outside air entering inside the property. 

After the testing period is completed the coupons are then analyzed using X-ray fluorescence (XRF)  to quantify the sulfur deposits on the coupons in ug/cm2 (micrograms per square centimeter).  Readings can then be interpreted to determine the presence of sulfide gases that may be present within the subject property.  A non-detect (ND) reading upon analyzing the test coupons indicates there are no detectable sulfur deposits on the surface of the coupons.   This helps lead to the conclusion there are no sulfide gases present at any significant or detectable levels during the course of the exposure period.   Positive readings for sulfur are compared against various controls and environmental conditions to draw comparisons and interpret results. 

See our video section for a walk through of this process.


Howard Ehrsam is the sole founder of Chinese Drywall Screening, LLC.  He has a bachelor's degree from the University of Florida in Civil Engineering.  He worked for Whiting-Turner in Central Florida for 8 years building theme park and commercial projects before moving to Port St Lucie in 2003 to start a new career in commercial development.  From 2003 to 2009, Howard managed various projects for Tradition Development, a master planned community developer.  Howard's certifications and licenses include Professional Engineer (PE), Certified General Contractor (CGC), LEED AP along with numerous specialty and private certifications. Howard enjoys life on the Treasure Coast with his beautiful wife of 23 years and 3 fantastic children.

In 2007, it was discovered that one of his properties was having characteristics understood to be caused by tainted drywall from China and he experienced the process of having it removed.  By way of his personal experience and being the president of a condo association with 80 tainted units, Howard quickly became the "go-to" resource for helping others.  The combination of his professional experience, dealing with the issue first hand, helping others and continual research has put Howard in a position to be an excellent resource for others in dealing with the Chinese Drywall phenomenon.

Howard Ehrsam and his team of inspectors have done over 3,000 inspections and the number grows daily in single family and multifamily residences, commercial and medical offices, warehouses and retail establishments.  In addition, he sat on the ASTM and AIHA drywall committees and has spoken at many conferences, symposiums and luncheons on Chinese drywall.   Howard has also been featured on many news articles and TV programs.

Contact Us


10815 SW Tradition Square, Port Saint Lucie, FL 34986

For more information or to schedule an inspection, call 772-224-8660 or Toll Free at 855-CDW-HELP (855) 239-4357.


Daily: 9am - 6pm

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Resource Videos

Walk through video of problem areas where builder left Chinese drywall behind tile and other areas along with debris that caused continued corrosion and problems for owner. 

Inspection of property with different types of drywall

Inspection and testing of a condo reveals low strontium domestic drywall, mid range Taishan/corrosive drywall and high stronium non-corrosive Chinese drywall. 

Selective Removal of CDW

Selective of CDW in a property with a mix of Chinese drywall and domestic drywall.

Suspected CDW is actually Well Water case

Blackening can cause alarm and many think this is caused by CDW, however in this case the cause of the corrosion was issues with the well water system at the property.

Environmental Corrosion Testing

How CDW debris from a bad remediation still causes issues

Overview of how debris from poor Chinese drywall remediation can re-corrode copper plumbing and wiring. 

Remediation Inspection with Issues

Property walk-through reviewing various issues with remaining cdw and debris.