Chinese Drywall Testing Techniques and Technologies


Chinese drywall testing involves analyzing samples for known marks that are indicative of defective drywall. Although several less expensive alternatives are being marketed, but FTIR and XRF are the future of accurate drywall testing.

Unequivocally, FTIR and XRF testing have been proven by the Consumer Products Safety Commission to be the most reliable drywall tests, demonstrating a reliability of 98% and 99%. These tests analyze drywall samples for carbonate sulfide and strontium respectively.


Each of these tests provides near perfect accuracy. A drywall test that utilizes both technologies in tandem overcomes any sampling contamination and allows for a complete picture of the home's composition. Drywall compound, or mud, can show up in FTIR analysis as a false positive for drywall. That compound, however, does not affect XRF Chinese drywall testing.

It should be noted that these technologies, when used properly, do not produce false negatives in testing.

Why are not all inspectors offering Chinese drywall testing that includes FTIR and XRF?

These technologies are not new. FTIR has been the backbone of material analysis for quite some time. This technology is readily admitted in a court setting as evidence. Several labs in the United States even offer to analyze drywall samples as part of a test. The problem is that, in this setting, each sample costs $ 150 to $ 200 for analysis on just one of the two machines. Analysis on the second will involve another $ 150 to $ 200. An average home contains upwards of 150 boards of drywall. In this environment, comprehensive Chinese drywall testing would involve $ 45,000 in testing fees alone. Add to that the cost of collecting samples and the insurance policy premium, and testing could cost $ 50,000.

Obviously, that is not price that the vast majority can afford. That cost is not a feasible option. Our testing protocol is the only affordable and insurable option on the market today.

What does FTIR testing involve?

FTIR, or Fourier Transformed Infrared Spectroscopy, relates on the measurement of infrared light that either passes through or is reflected by a sample. The resulting spectrum is compared against a library of known molecular fingerprints. No two compounds will produce the same results under FTIR analysis, creating a powerful tool for identifying unknown compounds at a molecular level.

As it relates to Chinese drywall testing, FTIR is used to identify carbonate sulfide, a marker that the CPSC has identified as unique to defective drywall.

FTIR has been central to laboratory analysis for nearly seventy years. This technology is well established and is respected and accepted within a court room setting. The fact that this technology is so reliable and well established further reinforces its use for such high stakes testing.

What does XRF testing involve?

XRF, or X-Ray Fluorescence, drywall testing involves bombarding a sample with X-Rays and measuring the effects. Each element produces a different energy under this condition and the results are used to identify the various compounds in a sample.

As it relates to a Chinese drywall test, XRF is used to identify strontium, which the CPSC has identified as a unique marker of Chinese drywall .

Who determined that these technologies are reliable for this testing?

The Consumer Products Safety Commission (CPSC) has concluded in their most recent report that these technologies are the most reliable Chinese drywall testing equipment.

"Using both FTIR and XRF measurements of carbonate and strontium, respectively, was there before determined to be the most sensitive and specific marker of imported drywall."

– Draft Final Report CPSC Drywall and Indoor Environmental Quality Assessment. November 18, 2009. Pg. 104 of 128.

"Results from this study indicate that the concentrations of Strontium measured by XRF and carbonate ion (carbonate) using FTIR, determined that drywall can be used in combination to reliably identify suspect drywall."

– Draft Final Report CPSC Drywall and Indoor Environmental Quality Assessment.November 18, 2009. Pg. 1 of 128.