Testing antimicrobial paint efficacy on gypsum wallboard contaminated with Stachybotrys chartarum
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Published on: December 5, 2020
M Y Menetrez1, K K Foarde, T D Webber
1U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, Air Pollution Prevention and Control Division, Research Triangle Park, North Carolina, USA. menetrez.marc@epa.gov
Abstract:
The goal of this research was to reduce occupant exposure to indoor mold through the efficacy testing of antimicrobial paints. An accepted method for handling Stachybotrys chartarum-contaminated gypsum wallboard (GWB) is removal and replacement. This practice is also recommended for water-damaged or mold-contaminated GWB but is not always followed completely. The efficacy of antimicrobial paints to eliminate or control mold regrowth on surfaces can be tested easily on nonporous surfaces. The testing of antimicrobial efficacy on porous surfaces found in the indoor environment, such as gypsum wallboard, can be more complicated and prone to incorrect conclusions regarding residual organisms. The mold S. chartarum has been studied for toxin production and its occurrence in water-damaged buildings. Research to control its growth using seven different antimicrobial paints and two commonly used paints on contaminated, common gypsum wallboard was performed in laboratory testing at high relative humidity. The results indicate differences in antimicrobial efficacy for the period of testing, and that proper cleaning and resurfacing of GWB with an antimicrobial paint can be an option in those unique circumstances when removal may not be possible.
Insights
Antimicrobial paints show potential for controlling indoor mold growth on gypsum wallboard (GWB). Laboratory tests indicate these paints can be effective in preventing mold regrowth on GWB surfaces, offering an alternative to removal.
Area of Science:
- Environmental Science
- Microbiology
- Building Science
Background:
- Indoor mold contamination, particularly from Stachybotrys chartarum, poses health risks.
- Standard practice for mold-contaminated gypsum wallboard (GWB) is removal and replacement.
- Testing antimicrobial efficacy on porous materials like GWB presents challenges.
Purpose of the Study:
- To evaluate the efficacy of antimicrobial paints in controlling mold regrowth on GWB.
- To assess the potential of antimicrobial paints as an alternative to GWB removal.
Main Methods:
- Laboratory testing of seven antimicrobial paints and two common paints on S. chartarum-contaminated GWB.
- Experiments conducted under high relative humidity conditions.
- Assessment of mold regrowth and antimicrobial efficacy over the testing period.
Main Results:
- Significant differences in antimicrobial efficacy were observed among the tested paints.
- Antimicrobial paints demonstrated varying degrees of success in inhibiting mold growth on GWB.
- Proper cleaning and resurfacing with antimicrobial paint showed promise.
Conclusions:
- Antimicrobial paints can be an effective strategy for managing mold on GWB in specific situations.
- This approach offers a viable alternative when GWB removal is not feasible.
- Further research may refine the application of antimicrobial treatments for indoor mold control.
