Premature deterioration of pressure-treated wooden structural components was discovered in the exterior wall and foundation systems of over 100 agricultural facilities across the southeastern United States. As the affected members are integral to the structures' lateral force-resisting system, the deterioration raised concerns regarding long-term structural stability and serviceability. The facilities, constructed between 2011 and 2018 using largely similar designs, exhibited varying degrees of deterioration with no clear relationship to age or geographic location. ESi was engaged to determine the cause of the deterioration, evaluate contributing factors, and determine liability in a multi-party litigation involving several million dollars in claimed damages.
Our Approach
ESi performed a comprehensive root-cause investigation that combined field evaluations, laboratory analysis, engineering analysis, and forensic document review. Our team conducted site inspections at more than 20 agricultural buildings across the southeastern United States, documenting the location, extent, and severity of biodeterioration affecting pressure-treated wooden structural elements. Representative samples were collected from facilities spanning multiple design iterations, geographic locations, and observed levels of deterioration.
The laboratory analysis included examining affected wood components to evaluate material condition, preservative treatment characteristics, and penetration of the preservative. ESi also performed a detailed review of structural engineering drawings, construction details, project records, and preservative treatment specifications associated with the facilities. ESi evaluated changes in design and construction practices over time, including multiple revisions to the engineering drawings during the seven-year period in which the facilities were constructed.
ESi identified several factors that contributed to the deterioration. These included deficiencies in the specification and selection of preservative treatment systems, design details that increased the potential for moisture accumulation within structural assemblies, and foundation and enclosure details that did not effectively manage water intrusion and drainage. The investigation also identified instances where wood elements were placed in direct contact with concrete creating conditions conducive to prolonged moisture exposure and accelerated biodeterioration. Additionally, project records indicated a lack of coordination regarding preservative treatment requirements until after deterioration concerns had emerged.
To validate our conclusions, ESi evaluated comparable facilities in the same region that utilized an alternate design. These facilities exhibited significantly fewer or no deterioration-related issues, providing an important basis for evaluating the relative influence of design, construction, and material-selection factors.
Services Utilized
Expertise Utilized
The Outcome
ESi’s investigation determined that the premature deterioration of the pressure-treated wood structural elements resulted from a combination of design, detailing, specification, and construction-related factors. The analysis demonstrated that inadequate design details and specifications failed to address moisture management, drainage, and long-term durability requirements associated with the unconventional structural system. These deficiencies, coupled with the selection of an unsuitable preservative treatment and construction coordination issues, created conditions that accelerated biodeterioration and compromised the structural stability of the facilities. ESi’s findings established the root causes of the failures and provided technical support for the resolution of multimillion-dollar claims involving multiple parties.
