Do Not Spray for Mold
Bottom Line: Do not spray for mold. Without thorough drying, spraying with bleach or Concrobium is a waste of time and can cause complications with health and property. If available, leave fans with the homeowners to help them dry out their walls.
Discussion: Mold damages property and can cause health problems. Some species of mold are universally toxic; others cause irritation when the spores are present in high concentrations; some people are especially sensitive to mold spores while others are not. While most mold is not toxic to most people, it is impossible to accurately distinguish among mold species without a laboratory test.
Consequently, use caution when working with mold. Wear a properly fitting N-95 respirator or dust mask (available at building supply stores) and rubber gloves. Do not attempt to clean up areas of mold that exceed ten square feet. After working with mold, wash using soap or hand sanitizer. Wash hands frequently, and change into clean clothes after working with mold or after participating in any disaster cleanup duties. Wash clothes that have been exposed to mold separately, and rinse the washing machine before using it to clean other clothes.
The benefits of spraying a bleach solution on porous materials to eliminate mold last no more than 24-48 hours, while creating substantial risks to volunteers, homeowners, and property. The Rutgers School of Public Health and other public health organizations now recommend AGAINST treating porous materials, such as wood studs, with a weak bleach solution to mitigate mold. This represents a change in best practices.
Wood studs must dry out for several days to stop mold. Without drying out studs, other actions such as scraping or spraying have negligible effects on mold.
In the face of need, it is extremely uncomfortable for many volunteers to do nothing rather than something, even if the action causes more risk than benefit. The church (and its unskilled volunteer labor force) is not currently in the position to perform and certify complete mold remediation over days or weeks. Therefore, we recommend leaving fans instead of spraying. While leaving one or two fans will not meet the needs of the survivors, it will eliminate many of the risks below, and teach the survivors that they need to dry out their walls before rebuilding.
Risks and Benefits of Spraying Bleach on Wood Studs to Eliminate Mold
Benefit | Risk |
---|---|
Bleach kills mold spores. | Bleach is a poison. |
On non-porous surfaces, a weak bleach solution is an effective way to kill and clean up mold. | An initial spray on porous surfaces (e.g. wood studs) kills surface mold spores, but does not penetrate very deep. Only a portion of mold spores are killed. |
In a weak water/bleach solution, the sprayed water evaporates into the air at a rate that depends on the ambient temperature, humidity, air circulation, etc. | In a weak water/bleach solution, the bleach quickly evaporates into the air, creating respiratory and eye irritation, and failing to leave a permanent mold-killing residue. |
It is common for people to use too much bleach, causing respiratory and eye irritation. | |
Without proper mold remediation (which includes dehumidification and scraping), moisture deep in the wood continues to nourish mold spores that were not killed on the surface. | |
Within 24-48 hours after the bleach/water spray has evaporated, new mold spores outnumber the mold spores killed by the bleach solution. Spraying was a waste of time. | |
Spraying for mold often gives people a false sense of security, because they do not realize its benefits have literally evaporated within 48 hours. | |
After having their studs sprayed with bleach, many homeowners mistakenly believe they have had full mold remediation and replace drywall, which quickly grows mold, costs money, and can create health risks. |
Aaron Titus validated this finding with a rigorous 2-month mold-growth and remediation test in his basement and garage. The field study evaluated 32 combinations of conditions that included wall construction, humidity, and treatment with bleach and Concrobium. Concrobium was chosen only because it was readily available at Home Depot. The study demonstrated that humidity and temperature overwhelmingly controls the rate of mold growth. Other factors such as treatment with bleach, Concrobium, or non-treatment had negligible impact on mold growth.
Read More…
- Policies on Service (Age, End Dates, Proselytizing, Proselytizing, etc.)
- Procedures (How to Get Work Orders, Absent Residents, Releases, Don’t Spray for Mold, Helping Unscheduled Neighbors, Reimbursement, etc.)
- Safety Information (Liability, Risk, and Insurance, Spiritual & Emotional Well-Being, Chainsaws, Nails, Risky Trees, etc.)
- Communication Strategies
- Checklist for Volunteers
- Statement of Work Performed (.docx)