Is It Mold or Mildew?

Real, Hype or Housekeeping Issues

By James F. McClung, Jr., President


Property owners and management companies know how hard it is to find and keep good tenants. If a tenant complains about suspected mold, it’s important to take it seriously. Having vendors in place, (mold consultants and remediation contractors), allows a property owner or management company to react quickly to a mold complaint. A quick reaction keeps the tenant satisfied, and is essential in minimizing risks for potential liability concerns. Owners, property management, and builders are being sued in record numbers over issues of mold. There are many avenues for managing microbial issues on a low-key and cost-effective basis that can provide solutions and reduce the potential for liability. Being well informed is crucial. Is it mold or mildew? Is your tenant’s complaint real or is it a housekeeping issue? This industry has a lot of hype, what is the right course of action? What you don’t know can cost you money!

The California Department of Health Services describes mold as “…simple, microscopic organisms found virtually everywhere, indoors and outdoors.” Therefore, there is no such thing as a residence being free of mold spores, as they are found indoors and outdoors. Mold spores can also be found in dairy products, beer, bread yeast and in many medicines, i.e., penicillin. In Southern California, we are used to associating allergies with spring and fall Santa Ana wind conditions. The winds cause mold spores from grass, trees, shrubs, etc., to become airborne along with other pollutants such as dust. For individuals who are susceptible to allergies, this is a ripe environment for varying types of reactions. Mold has been around for a very long time; early references can be found in the Bible.

Many wonder why mold has become more publicized than ever before. In recent years, testing methods have been developed that are more sophisticated, medical science diagnostic capabilities have improved, and the general public has more access to information. In addition, building materials being utilized since the early 1970’s have changed. Some of these materials are more susceptible to mold growth when a moisture intrusion source is present. An example is the former use of lath and plaster walls compared to the current, less expensive use of drywall. Drywall contains a paper backing and lath and plaster does not. Whenever sufficient moisture is present, the paper backing on drywall may promote the growth of mold. Many potential moisture intrusion sources exist in single and multi-family residences such as bathrooms (sinks / tub / shower enclosures / toilets), kitchens (sinks / dishwashers / icemakers), laundry rooms, and various types of plumbing throughout the structure. There are also outside sources that can affect the interior, including sprinklers (over watering), poor drainage, plugged exterior ground drains, and flowerbeds raised above the level of the concrete slab. Of course roof leaks can also impact the structure.

Mold cannot grow without a moisture intrusion source, (i.e., a water leak) and a porous material, (i.e., drywall, carpeting, wood). Mold will usually be embedded in the affected material and cannot be easily wiped off. To remediate mold, it may be necessary to cut out and conduct remediation activities in the affected area(s).

During cold weather, doors and windows tend to be kept closed and a lack of ventilation can become an issue leading to mildew that can often be mistaken for mold. This winter there has been an increase in tenant complaints regarding mold growth in bathrooms, bedrooms, and around windows. The most common complaint is mold growth on bathroom ceilings, walls and grout in the shower. We have all seen how fast a bathroom mirror will fog up from the steam (humidity) of a hot shower. The longer the shower, the more steam (humidity) is produced, which will condense on cool surfaces (mirror, ceiling, and walls). Without adequate ventilation, the humidity will remain on the various surfaces, including shower grout, and will not adequately dry. This may form a surface fungal growth, which is usually mildew. In addition, without adequate ventilation in a bathroom, the humidity will escape into adjoining rooms once the bathroom door has been opened. Again, the humidity will condense on cooler surfaces such as the interior of outside walls and windows. This condition is more prevalent in rooms located on the north sides of buildings where direct sunlight does not have an opportunity to warm the interior of an exterior wall or window. A fuzzy type of fungal growth, caused by humidity condensation and lack of ventilation, can also form where there is dust on walls behind dressers, dirt and grime in the corners of windows and window casings. In closets, this fuzzy type of growth may be found on shoes, clothes, etc. Numerous studies have shown the relationship of elevated humidity levels, cool surfaces, and the effects of mildew growth.

Is it mold or mildew? Is your tenant’s complaint real or is it a housekeeping issue. Many times after investigating affected areas, we have found some of the following conditions:
• There was no a water leak

• Elevated humidity levels were due to inadequate ventilation in bathrooms

• Limited usage of heating system to reduce humidity and to warm wall surfaces

• Inadequate housekeeping in showers, around windows, etc.

• Dirt & grime on metal window casings and the window track

• Dirt & grime along a wall causing furniture / bedding limited air circulation.

An easy way to tell if the microbial growth is on the surface vs. embedded in the substrate is to fold several sheets of toilet tissue and gently rub the surface of the fungal growth. If the growth is easily wiped off the surface, usually it will be a type of mildew. A general cleaning of all surfaces, utilizing wet wiping with an anti-microbial solution will be necessary. The objective of the cleaning is to remove excess dust and residual microbial spores. Once the cleaning has been completed, it will be necessary to find a solution to the elevated humidity levels to prevent a return of the microbial growth. As an example, humidity levels can be reduced in bathrooms through either opening the window or installing a higher efficiency exhaust fan. For bedrooms, it may be necessary to utilize a portable dehumidifier during the winter months. Through increased housekeeping of walls, windows, closets, furniture, and bathrooms, most microbial growth can be prevented. The key can be as simple as air movement, keeping surfaces clean, and reducing humidity.

As mentioned above, mold will usually be embedded in the substrate and will need to be cut out to remove it. Mildew is usually a surface growth and many times can be removed through scrubbing the surface. Regardless of the microbial growth, it is highly recommended that maintenance personnel, on-site management, or the property owner respond promptly to the tenant’s concern. This will include not only all reports of mold / mildew, but also moisture intrusion, overflows, non-working heating and air conditioning systems, bathroom exhaust fans, bathroom ventilation windows, kitchen fans, kitchen vent systems, and laundry room exhausts. Each complaint should be investigated and documented including any appropriate responses for repairs and / or remediation activities.

Many times the tenant’s complaints can be easily solved / fixed without the need of an outside vendor. However there will be times when an expert may be needed.

Remember – what you don’t know can cost you money.

James F. McClung, Jr., President
American Environmental Specialists, Inc.

American Environmental Specialists, Inc., (AES) is a veteran owned environmental consulting firm specializing in Mold, Asbestos, and Lead-Based Paint. AES technicians are Certified Lead Paint Inspectors/Risk Assessors with expertise in the 2010 Renovation, Repair & Painting Rule.

Contact Info

Corporate Office
American Environmental Specialists
15183 Springdale St
Huntington Beach, CA 92649
Office: 714-379-3333
Fax:    714-379-3338
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