Richard P. Vlosky and Todd F. Shupe
Although it is uncommon in most homes, toxic mold, also known as black mold, has become a major issue for some home builders and homeowners in the United States. The effects have run the gamut from disposal to litigation. Although the Centers for Disease Control and Prevention has reported there is no test that proves an association between black mold and particular health symptoms, a number of lawsuits have been filed against wood products manufacturers and builders claiming that human health has been compromised by exposure to mold.
Mold and mildew, which appear as woolly or powdery growth, are microscopic fungi, low forms of plant life, that live off organic matter rather than a photosynthetic process. Mold spores can be found almost anywhere; they can grow on virtually any substance, provided moisture is present. They are always present in outdoor and indoor air, and almost all organic building surfaces, including lumber, can provide nutrients to support growth.
Mold can grow equally well on inorganic materials such as concrete, glass or plastics that may have nutrients on the surface. Of the more than 100,000 species of mold, at least 1,000 varieties are common in the United States. Mold is most likely to grow in the presence of water or dampness, such as in bathrooms and basements.
In buildings, high humidity is the most common cause of mold growth. The moisture is sometimes a result of construction defects or maintenance problems such as leaking windows or roofs, failed sealant joints, inadequate or missing flashing, leaking pipes, cracks in the siding or poorly designed air-conditioning systems. Mold can grow on materials with high cellulose content such as paper facing on drywall, dropped-ceiling tiles and wood that becomes chronically moist or water-damaged because of excessive humidity, water leaks, condensation or flooding.
In 2002, LSU AgCenter researchers conducted a nationwide study to understand and compare awareness, attitudes and concerns regarding mold among home builders, new-home homeowners and real estate agents. The samples included 1) the top 500 U.S. home builders based on sales, 2) a national random sample of 1,500 new home homeowners and 3) a national random sample of 1,000 real estate agents.
The 288 respondents indicated that home cost is the most important home building, purchase or sale criterion, followed closely by resale value and energy efficiency. Being free from mold was ranked next, followed by resistance to wood-destroying insects. Respondents did not show a strong understanding of how mold forms in new construction, although home builders had the highest level of understanding. They had a higher overall level of agreement that with proper construction methods, mold is preventable in new home construction.
Only 10 percent of homeowners believe that mold is an issue in their neighborhoods. However, 35 percent of home builders and 19 percent of real estate agents said this is an issue in the homes they build or sell. More than 60 percent of respondents in all groups generally agreed that mold can be prevented if the homeowners regularly inspect their houses and quickly repair any water leaks they discover.
Respondents had a number of concerns related to mold. First ranked is “health issues for homeowners” followed by “liability/chance of being sued” (builders and real estate agents only). Although homeowner health concerns ranked first, only 24 percent of homeowner respondents identified this as an issue. Conversely, more than two-thirds of home builders and real estate agents are concerned about this issue.
When asked whom they would most trust to provide mold safety and remediation, home builders had a significantly higher level of trust for the National Association of Home Builders, builders associations and individual builders, while real estate agents had a higher level of trust for real estate agent associations, and new home homeowners trusted the Environmental Protection Agency most.
The last question in the study asked respondents if they would like to receive more information on preventing mold. All respondent groups agreed they would like to receive such information.
Keeping in mind that responses are self-reported, on average, home builders appear to be most informed about mold issues while new home homeowners are least informed. Similarly, home builder respondents had the highest level of concern about mold and homeowners were least concerned.
An understanding of the mold issue from these points of view can aid private companies, public policy makers and extension professionals in developing and disseminating unbiased, useful information to these and other groups. Results indicate that overall, respondents do not have a strong understanding of how mold forms in new construction and desire information. Opinions and concerns from these groups can help wood products manufacturers and home builders understand this issue and develop educational programs and strategies to illuminate customers and the general public about facts and myths about mold.
Richard P. Vlosky, Professor and Director, and Todd F. Shupe, Associate Professor, Louisiana Forest Products Development Center, School of Renewable Natural Resources, LSU AgCenter, Baton Rouge, La.