Airborne fungal tests conducted shortly after a major renovation of a 30-year-old elementary school showed indoor levels of Acremonium, Aspergillus, and Chaetomium fungi up to 70 times higher than outdoor levels. The cause of the elevated indoor fungal levels was traced to new vinyl base molding installed in the school during the renovation. Vinyl base moldings have been used in building construction for at least 50 years. Ten years ago, to address concerns about indoor and outdoor air pollution from the off-gassing of VOCs from solvent-based adhesives, contractors switched from solvent-based to water-based adhesives. This change has increased the likelihood of fungal growth behind vinyl base moldings. Solvent-based adhesives are nonpolar compounds and do not absorb water (a polar compound) as readily as water-based adhesives (polar compounds). There are two problems: the water-based adhesive is more likely to absorb water and the vinyl base prevents the adhesive from drying quickly. The presence of water behind the vinyl base increases the potential for fungal colonization of the adhesive and the vinyl base. Water-based adhesive manufacturers need to address the potential for fungal growth behind vinyl base moldings, especially in situations where building maintenance staff routinely clean the floors using wet methods.

Authors: Paul J. Ellringer, P.E., Carol A. Ellringer, Linda K. Olson, Katy Boone Nadine Engbrecht-Schaff

Citation: Indoor Air Quality 2001 Moisture, Microbes, and Heath Effects: Indoor Air Quality and Moisture in Buildings Conference Papers

Keywords: November, California, 2001, IAQ