Preventing Mold Growth in Indoor Environments [before it happens]
Mold requires water to grow. Thus it is important to prevent moisture problems inside buildings.
- The best way to prevent mold growth is to keep all materials in the building as clean and dry as possible. Additionally, it is important to make sure living spaces are well ventilated and that the relative humidity remains below 60 percent.
- Inspect the building to look for water damage, leaks or condensation. If found, correct the reason for the excess moisture as soon as possible. Common sources of moisture includes leaky faucets, washing machines, toilets, refrigerators, dripping pipes and/ or cold surfaces where moisture condenses. When a new spill occurs, make sure to clean it up immediately.
- Sources of standing water promote both mold and bacterial growth. Cover sump pump holes with Plexiglas or metal (not wood), enclose fish tanks, and ensure that basement drains (for a/c hoses, humidifiers, washers) function properly and are not clogged.
Dehumidify the air to prevent mold growth.
- Using a dehumidifier, air conditioner, and/ or furnace can help reduce humidity (dry out) the air and thus prevent mold growth.
Prevent mold and water entry in crawlspaces and basements.
- Install a vapor barrier (6 mil polyethylene plastic) over the ground in the crawl space to prevent moisture from evaporating from the soil and entering the home. Damp crawl spaces can lead to mold growth on wood floor joists and floor board above the soil.
- Moisture in crawlspaces creates an environment perfect for mold growth (dark, stagnant air, damp).
- Once mold grows, the mold spores can gain entry into the home through small cracks in the subfloor, around unsealed plumbing fixtures and/ or via the HVAC system.
- Grading around the home should slope away from the foundation walls to prevent water entering the crawlspace and/or basement.
- The grading should slope approximately 1 inch per foot for the first six feet around the home.
- Improper rainwater drainage from the roof is one of the most common causes for flooding basements and crawl spaces.
- Make sure that gutters, downspouts and splash blocks are connected properly, not blocked with vegetation (like leaves and twigs), and are functional.
- Install downspout extensions and use drainage techniques to direct water at least three (3) feet away from the foundation.
- Keep the gutters clean. Any tree branches that hang over the roof should be trimmed to prevent future gutter problems.
- Window wells should be covered with a weather resistant cover to prevent the pooling of water and/ or debris.
Vegetation around the home and/or business.
- Vegetation planted too close to the exterior of the house can obstruct airflow, preventing quick evaporation to dry out the siding of the house. This is especially true for walls that do not receive much sunlight (often the north side of the house)
- Clear shrubbery away from building or home so that moisture is not retained against the foundation. Mold is commonly found on the underside of leaves.
- Store firewood away from the home.
- Recent studies by the Environmental Protection Agency (EPA) and the Consumer Product Safety Commission (CPSC) have shown that ultrasonic and impeller (or “cool mist”) humidifiers can disperse materials, such as microorganisms and minerals, from their water tanks into indoor air. Proper care and cleaning are important.
- Keep central furnace humidifier units properly maintained, in accordance with the manufacturer’s directions. Clean and change the filter on an annual basis.
- Condensation on walls or windows indicates that the humidity is too high and needs to be adjusted. A high relative humidity can encourage unwanted microbial growth.
- Prevent moisture due to condensation caused by increasing surface temperature (insulate or increase air circulation) or reducing the humidity level in the air.