Study finds exposed wood can resist microbial growth

Researchers at the University of Oregon have found that exposed wood can resist microbial growth after a brief wetting.

The findings of their study bolster the case for using mass timber in hospital construction and dispel widespread misperceptions about wood and pathogens, according to a report at the University of Oregon news site.

“People generally think of wood as unhygienic in a medical setting,” said assistant professor Mark Fretz, co-director of the university’s Institute for Health in the Built Environment and principal investigator for the study. “But wood actually transfers microbes at a lower rate than other less porous materials such as stainless steel.”

“We wanted to explore how mass timber would stand up to the everyday rigors of health care settings,” said Gwynne Mhuireach, a UO research assistant professor. “In hospitals and clinics, germs are always present, and surfaces occasionally get wet.”

The experiment consisted of blocks of cross-laminated timber sealed in disinfected plastic boxes with controlled temperature and humidity. Air was filtered and exchanged at rates similar to how they are specified by hospital codes.

The team sprayed the blocks with tap water, inoculated them with a cocktail of microbes commonly found in hospitals, and took samples over four months. An empty plastic box was used as a control. The plastic box had more viable microbial abundance than the wood samples, excluding the first 14 days after inoculation.