The presence of mold in an indoor environment is typically due to things such as chronic humidity and condensation, poor ventilation, improper appliance exhaust, improperly mitigated water damage, or a combination of these conditions. Whatever the cause, the mold growth should be inspected by a qualified mold remediation contractor. It is important to investigate the source of mold growth, the scope to remove the mold, and the steps to correct the moisture source that lead to the mold growth. Often this may require enlisting the services of other contractors. For example, if water proofing, weatherization, air sealing and insulation are required it may be necessary to consult other contractors.
For as much quality information that is available about mold remediation there is an equal amount of misinformation. Proper removal of mold must include three steps:
- clearance testing.
Corrective measures to prevent recurrence MUST be taken after mold removal as well.
Within these steps are the opinions of contractors, advice from friends, and an endless supply of searchable articles and sites on the web. This can often leave a building owner more confused than informed. What are the right steps? What are things to avoid?
A common misconception is to spray bleach and water to kill mold. Mold spores are very difficult to kill with chemical applications. Bleach is quite ineffective in killing mold and even in a dead or inactive state mold can still be a respiratory hazard. Mold produces mycotoxins which are secondary metabolites (not involved in primary functions of an organism) that are capable of causing illness and disease in humans and other animals. This is why a physical removal of microbial growth is needed to ensure a healthy indoor environment. Physical removal can range from hygenic cleaning and hepa vacuuming to media blasting or controlled demolition of affected finish materials.
Ventilation of a crawlspace or basement will “air out” growth. The presence of open perimeter ventilation in a crawlspaces or opening basement windows can do far more harm than good depending on outdoor conditions. By allowing outside air in which can be quite warm and humid you can actually cause or elevate condensation within basements and crawlspaces. A soft drink can taken from a refrigerator on a hot summer day is a great example of condensation. When placed in the warmer air outside the refrigerator, water vapor condenses and returns to liquid form on the can. The cooler surfaces of a crawlspace or basement act the same as the can. It is important to keep those environments free of excess moisture, closed and mechanically evacuate excess moisture from the air by means of a dehumidifier (be sure to select a unit sized appropriately for the space it will be used in).
Paint over the mold to seal it. Painting or covering mold growth with another material allows the growth to continue to consume the surface on which it is growing. For example, spraying a color blocking primer on roof sheathing will cover cosmetic staining, but if not properly cleaned it may not stop the mold from continuing to consume the sheathing which will in time degrade its structural integrity. Structural wood must be remediated properly before any sealant or paint is applied. Media blasting such as dry ice or soda blasting is a typical method of mold removal for roof sheathing.
Mold in a basement doesn’t affect air quality on other levels of a home. The Stack Effect, which is airflow that results from air rising creates negative pressure at the bottom of the building and a positive pressure at the top. This negative pressure causes air to rise from one floor to the next. If there is mold growth in a basement detached mold spores can travel into other areas because of the stack effect. Those spores can then settle out on surfaces and dust in these new areas. Air Quality testing by a qualified industrial hygienist can verify through air and surface sampling if mold is present outside of visibly impacted areas.
If you are seeing what you believe to be mold in your home be sure to: limit your entry into the affected area, if applicable enlist the services of an industrial hygienist, and do your research carefully. Mold removal is not a do-it-yourself project for the average homeowner. Improper removal of mold can cause the spread of spores to unaffected areas. Proper containment, air pressure monitoring, and personal protective equipment (PPE) are essential to protect both the building occupants as well as mold remediation contractor. The process of identifying origin, remediation of the growth, and advices on corrective measures can be achieved by working with a certified mold remediation firm.