DOWNERS GROVE – The University of Illinois Extension in DuPage County reminded residents this week to thoroughly clean and disinfect basements affected by flooding this season to prevent against harmful mold.
Heavy rainfall and flash flooding can lead to water accumulation in basements, and the extension's educator said water in a small portion of a basement requires the same cleaning and disinfecting effort as several inches across the entire basement.
“Receding floodwaters and infiltrated water may contain sewage and other contaminants, including pathogens that are harmful to people,” said U of I Extension educator Stanley Solomon. “Mold is the long-term concern from the flood damage. Mold can start growing on wet materials in 24 to 48 hours so it’s important to get all materials dried as quickly as possible.”
Water and electricity is a dangerous combination, Solomon added.
“Don’t enter areas where electrical equipment or outlets may be exposed to the standing water,” he said.
Solomon recommended wearing rubber gloves, eye protection, and clothes that can be immediately laundered – or a protective suit – as a minimum. A proper fitting N-95, N-100 or HEPA-rated respirator/mask is recommended, especially if there is any indication of mold or if there have been overland floodwaters in the home from swollen streams and rivers.
Various water-soaked materials require different treatment plans.
Salmon recommended removing porous materials such as drywall, carpet, and carpet pad that are wet or have indications of mold growth.
Highly absorbent porous materials such as carpet padding, drywall, insulation, and furniture stuffing should be discarded in most cases. These usually cannot be dried quickly enough to prevent mold growth and are difficult to adequately clean, according to Salmon.
Non-porous materials such as glass, hard plastic, metal, and countertops can be cleaned with standard cleaning methods. A biocide such as chlorine bleach is not necessary.
Semi-porous materials, such as structural wood, should be exposed to air as quickly as possible. Property owners can remove mold from these surfaces by scrubbing, or more aggressive methods such as sanding.
Semi-porous materials like flooring and counter underlayment may need to be removed to ensure that the structural elements can be properly dried, according to Salmon. For example, vinyl flooring could be cleaned, but may need to be removed to dry or replace the subflooring.
Salmon recommended that residents clean most surfaces with a non-ammonia soap or detergent. After cleaning semi-porous materials, disinfect the area using a bleach and water solution or another disinfectant. For cleaning surfaces, a mixture of one-fourth cup of bleach with one gallon of water should be adequate. The surfaces should remain wet for about 15 minutes to allow for disinfection. A higher concentration of 1.5 cups of bleach per gallon is recommended for wood and concrete surfaces that cannot be thoroughly cleaned.
Salmon reminded residents not to mix ammonia and bleach because the fumes are toxic.