When does wet drywall not grow mold?

Mold and moisture are important factors affecting indoor health and for material degradation. However, an understanding of the relationship between different moisture parameters and microbial growth remains elusive. We designed an experiment to study the impact of liquid water on moisture parameters and microbial growth. Naturally inoculated samples of four types of drywall were wet with different water sources and exposed to varying hygrothermal conditions. Microbial growth was assessed using qPCR methods. Although the relationships between moisture parameters were enlightening, minimal microbial growth was detected on most samples. When growth was detected, it appeared to be independent of the experimental variables (wetting amount, hygrothermal conditions post wetting, drywall type, and water type). This inconsistency and overall lack of microbial growth highlights the need for future investigation, including exploration of microbial dispersion as a limiting factor for indoor microbial growth. Subsequent phases of the study were improved based on these results.