Investigation of Faulty Gypsum Topping on Flooring

A home builder in California constructed a wood frame condominium building and used a gypsum topping product on the subfloor. This product is typically used for acoustic insulation and increasing the fire rating of a floor. The builder hired an experienced gypsum applicator to install the topping. After this occurred, finishes were placed inside the building, including cabinetry, drywall, and flooring. Within a couple months, significant amounts of mold was discovered in the oriented strand board (OSB) used in the floor. Workers cut into the floor and found that it was still wet. They were forced to tear out and replace some of the flooring, as well as some of the drywall.

The builder filed a lawsuit against the gypsum applicator, claiming that the gypsum topping was improperly mixed and installed.

CTLGroup represented the gypsum floor topping applicator in the case. Our work included a review of the project documentation and project history, including the decision to switch from originally specified portland cement topping to gypsum topping. We also reviewed the testing performed by the opposing party's experts, as well as the weather history during the time of the installation and construction.

Our team made reference samples and examined samples taken from the job site. We used reference samples with different amounts of water in each batch, from being under-watered to over-watered. We measured the internal relative humidity of the gypsum topping samples as they dried in a controlled lab environment and demonstrated that, even under the best conditions, it probably would have taken several months for the topping to dry before the floor coverings could be installed. Given the extremely humid weather – based on the weather history – we developed the opinion that the gypsum topping would not have dried enough by the time the coverings were installed.

Furthermore, CTLGroup's findings included the following:

  • Experts representing the opposing party did not present credible scientific evidence that the product was improperly mixed and installed. Their claims were not supported by properly conducted scientific tests admissible in court.
  • The opposing party was also unable to provide evidence that any moisture testing had been performed prior to installation of the flooring. This was the responsibility of the general contractor and flooring subcontractors. If moisture testing had been done, as recommended by the product manufacturer, then the high moisture condition would have been discovered and the problems could have been mitigated before trapping moisture in the floor by application of flooring.
  • Chemical analysis (using ASTM procedures) of the job site materials found that the product had been properly batched according to the manufacturer's instructions.
  • Microscopical analysis of the job site materials did not indicate that the materials were overwatered.

CTLGroup provided the client with expert opinions, properly conducted lab tests and evaluations of the product. Due to our extensive expertise, thorough work and comprehensive approach, we successfully helped our client negotiate a favorable settlement and avoid arbitration.