Mold Web Course/Chapter 3/Lesson 1

by the Environmental Protection Agency

Lesson 1Where to Look for Mold Contamination - Building Investigation

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As discussed in Chapter 2, mold can grow in wet or damp spots in a building, or where humidity is high. Therefore, it is important to look for indoor areas where moisture is a concern. Chapter 2 lists a number of factors that may contribute to indoor humidity and moisture problems. Reports of any of these problems should be investigated. If there has been a leaking pipe in the basement, for example, items such as carpets, paneling, and drywall there should be checked for water damage or mold growth. It is important to dry items quickly to prevent mold growth; in most cases, items dried within 24-48 hours will not become moldy.

Carpet
Carpet backing or padding must be dried in addition to the carpet or mold will likely result.

Look for mold in wet or damp places and in places that smell moldy or musty. Indoor mold growth should be cleaned up. Remember that mold comes in many colors, not just black.

Hidden Mold Growth

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In some cases, indoor mold growth may not be obvious. Mold does not need light to grow: it can grow in dark areas and on hidden surfaces, such as the backside of drywall, wallpaper, and paneling; the top side of ceiling tiles; and the underside of carpets and pads. Possible locations of hidden mold also include damp areas behind walls and in crawlspaces, inside pipe chases and utility tunnels (areas in walls where water and other pipes are run), on acoustic liners in ventilation ducts, and on roof materials above ceiling tiles.

Investigating hidden mold can be difficult and may require a professional with experience investigating water and mold-damaged buildings. Specialized equipment such as borescopes and moisture meters, and in some cases special sampling techniques, may be helpful in locating and identifying hidden mold areas.

Investigating hidden mold requires caution since disturbing moldy areas may spread mold throughout the building. Opening and closing air handlers, for example, can send high levels of dust and mold into the air. Personal protective equipment (PPE) is not always needed when looking for mold, but it should always be available. If mold might be released into the air, investigators should use PPE to reduce exposure.

Homes

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Areas that are always or often damp, such as bathrooms, laundry/utility rooms, and basements, are common locations for mold growth in homes. Regularly check areas that have been or are likely to get wet. If you hire a home inspector, building inspector, or other professional to locate a water or mold problem, make sure the professional has experience identifying and locating mold and water problems. Check references and look for membership in professional organizations.

Commercial Buildings, Large Buildings, and Schools
A key step when looking for mold in a building is to determine whether there has been a water leak. Maintenance personnel are frequently among the first to know when moisture problems have occurred. In some cases, management or health and safety personnel will have been notified. Either way, touring the building with maintenance or other personnel involved with the water problem may be helpful.

If possible, crawl spaces should be included when examining the building. (A white, soluble fibrous material on the soil of the crawl space may be alkaline salts, not mold, indicating moisture has been a problem and suggesting that the area should be more extensively inspected.)

Moldy or musty odors should alert an investigator to the possible presence of mold. Complaints of past water problems or water leaks should be investigated to determine how much water was involved and how quickly it was removed.

The building's air-handling system should be inspected to determine whether it is moldy. Moisture may collect in the ventilation system due to poor condensate pan drainage, poor roof drainage, or high humidity in the ventilation ducts. In some cases, water may enter the ventilation ducts from a leaky pipe. A contaminated ventilation system may spread mold spores throughout the building and should be considered a high priority for investigation and repair. Ventilation system mold contamination should be mitigated as soon as possible in a manner that does not expose building occupants to dust and mold spores. (See Chapter 6.)

During the building survey, any moldy or damp odors should be noted because damp or musty odors suggest that water is or was present and mold growth is likely. Occupant complaints of odors and health problems also should be investigated.