Mold and Mildew

Mold vs. Mildew

The terms mold and mildew are often used interchangeably. They are indeed similar but not really the same. It is important to understand their similarities and differences before attempting to prevent their occurrence or to clean up or remediate after finding them in your home or business.

Both mold and mildew are a form of fungus. Mildew is actually a type of mold. They are members of a large variety of micro-organisms which include fungi, algae, rusts, yeasts and bacteria. The ability to exist on just about any type of material gives microorganisms the dubious distinction of being called the chief agents of deterioration.

The color and texture of mold and mildew are also ways to help distinguish each of them. Active mold is usually red, green, blue and black and tends to be fuzzy and slimy. Mildew is usually powdery and most commonly comes in gray and white.

Mildew thrives on surfaces where moisture content is very high. Examples are ceilings, walls, floors, window sills, leather and paper, etc. Mildew is usually the culprit in showers, bathtubs, sinks and toilets. There is even a type of mildew that is specific to wool carpets and rugs! A certain type of mildew can be found as yellow spots on leaves or fruits.

While mold can survive on non-living materials such as tile and plastic as well as on plants, mildew specifically seeks out animal and plant goods and is especially devastating to crops.

Regardless of the particular organic material that may be present, neither mold nor mildew can resist surfaces where there is moisture. They both prosper in dark, humid, damp and poorly ventilated environments.

Mold and Mildew Are Invisible and Odorless!

Does it surprise you to know that mold and mildew are invisible and odorless?! What are those black, green, yellow, etc. spots then? And what about that moldy odor? What you are actually seeing and smelling is the end result of the digestive process of these micro-organisms as they eat through your organic possessions.

Both mold and mildew, since they are forms of fungi, do not need to derive their energy for growth from light. Instead, they need organic materials to supply their nutrients.

How Do Mold and Mildew Spread?

Both mold and mildew spread by sending out massive amounts of spores (or seeds) that are always present in the air and are spread by air currents. Once landing on a host material, the spores must find sufficient moisture and food to germinate. If the spores cannot find moisture, they will remain in the air, lying dormant until moisture occurs.

Are Mold and Mildew Dangerous for Humans?

Mold and mildew cause many problems for humans. In particular, they can escalate asthma and allergies and mold can cause serious fatigue.

Are Mold and Mildew Beneficial to Humans?

Although all mold can cause ill effects, some molds actually have beneficial uses in the scientific and food industries. Molds are used in the production of some medicines such as penicillin, as well as some cholesterol lowering drugs and even some immune-suppressant drugs.

Molds are also used in the production of foods such as cheese, bread, soy sauce, etc. Molds are also essential for our environment for their role in breaking up waste and dead matter and thus helping in the fertilization of soil. Mildew does not seem to have any beneficial uses at all.

What Should You Need To Do To Prevent Mold and Mildew?

Control of and monitoring of the relative humidity in the home or business environment is of utmost importance in the prevention of mold and mildew. Relative humidity should always be kept below 65%. It is much less likely that spore germination will occur at around 45% to 55% relative humidity.

Since most home dehumidifiers only go to 50%, in problem situations of high humidity, such as a damp basement, it may make sense to invest in a commercial dehumidifier. A temperature between 64 and 68 degrees F. should also be targeted.

Any conditions that raise humidity levels need to be remediated. Some of these may be leaking pipes, gutters and downspouts, leaking roofs, cracked walls or windows, etc.

Proper humidity and temperature controls decrease the possibility of germination and thus growth of mold and mildew. It is of equal importance to maintain adequate air circulation, such as with a fan (especially in bathrooms). Moving air evaporates moisture. Caution: Do NOT use fans if mold is suspected to already exist so as not to disturb the spores and send them airborne.

In combination with lowering humidity levels, the home or business environment should be cleaned regularly to remain as free as possible of dust, dirt and organic debris that can feed spores.

After moisture is gone, the invisible spores will go searching again. Fans can move the air to keep evaporating moisture. You can also put a light on as microorganisms such as mold and mildew need not only moisture, high temperature and a food source but they also need darkness. Removing any of these four factors will deter their growth.

What If You Find Mold or Mildew in Your Home or Business?

Take out anything that has mold or mildew on it. Kill any remaining mold or mildew with a mildicide. Vacuum everything. Replace cardboard containers with plastic bins but make sure to position small boards on shelves under the bins in order to allow for continued air flow. You may want to spray walls with a commercial sprayer containing 10% sodium hypochlorite (bleach). Unfortunately, none of these actions will kill the spores so continuous monitoring of these areas is still necessary.

What Should You Do When a Flood Occurs?

Floods are a major cause of mold and mildew growth. Mold and mildew will begin to develop within 24 to 48 hours of any water exposure in the home, such as flooding, leaks, sewage back-up, overflows, etc. Mold and mildew will continue to grow until the source of the moisture is dealt with.

Steps to Take When a Flood Occurs

    1. Call your insurance company to see if the damage will be covered. Some policies require extra flood insurance if you are in a flood zone.

    2. Call a water damage restoration company immediately in the case of water intrusion. Doing this as soon as possible after you notice any water damage can make the difference between a relatively short job and a much longer, costlier one. Water damage must be caught within hours in order to prevent sheetrock damage and carpet and pad replacement. Affected areas can be dried with extraction, dehumidification equipment and engineering controls before mold has a chance to take over.

    3. The following questions should be answered to ascertain whether or not mold and mildew have had a chance to start (which leads to different skills and services). The answers to these questions will also help the water damage restoration technician decide what equipment needs to be brought to the site.

    The location of the water damage.
    The extent of the damage.
    The source of the water.
    Whether or not the water flow has been stopped.
    The size of the area affected.

Additional questions which help determine the degree of drying required:

    What exactly happened?
    When did the intrusion occur?
    Has this happened before? If so, was it professionally remediated?
    What are the walls made of?

What to Expect from the Professional

Once the proper information is obtained, technicians will come to the site to take hygrometer readings, both inside and outside the home or business. A moisture meter, penetrating or non-penetrating, will also be used to determine the severity of the damage. That way it can be determined which parts of the building are wet and also how deep the water level goes. These sensors can also help to see if water has stopped in the main affected area or gone under the wall into the next room.

If water needs to be removed, the professional water damage remediator will come prepared to do everything necessary to remove it. Sometimes this may mean drilling a hole into the ceiling or an otherwise restricted space to let the water out and allow air to flow.

Before any water extraction begins, the customer should be told of the extent of the damage, the types of equipment to be used and the length of time the operation might take. The customer should be given an opportunity to ask any questions and voice any concerns.

If an insurance adjuster is involved, the professional water damage remediation company should be happy to work with the adjuster to speed the completion of the job and return your home or business to its proper state.

The Water Damage Remediation Procedure

Removal of Affected Objects and Water

If furniture or other objects must be removed, this will be done first. Free-standing or running water will be removed from the surfaces of any affected items. After the contents are removed and protected, extraction of water will begin.

Water Extraction

Depending on the size of the water intrusion, equipment ranging from portable extraction units to heavy-duty truckmounted units will be used. The attempt will be made to remove as much water as possible from the area. Standing water will be removed first and then water will be removed from carpeting and pads.

Please note: If flooding is widespread and a company representative cannot get to you quickly, your local fire department may be prepared to extract standing water until actual remediation takes place. A carpet cleaning company should also be able to extract a majority of the water. Many carpet cleaning companies are also certified as water damage contractors.

Special Equipment

Air movers are special units that blow air with tremendous pressure across a surface to help it to dry out faster. An air mover will pick up moisture from the surface and the more air you can pass over the surface, the more rapid the drying.

The drier the air, the sooner the entire area will dry. Dehumidifiers pull the moisture from the air. What type of dehumidifier used (refrigerant or desiccant) will depend on the scope of the job. Refrigerant dehumidifiers can pull moisture at temperatures as low as 35 degrees F. Desiccant dehumidifiers are used in specific instances beyond the use of refrigerant dehumidifiers.

Monitoring and Metering
During the entire process of drying, the area must be continually monitored and the drying progress checked with meters. The drying equipment will have to be moved around to take full advantage of their capabilities.

Drying time can vary depending upon the density of the building material. Sheetrock dries out relatively quickly while wooden studs take longer. Plaster and concrete and any porous materials take the longest time to dry.

Carpets, pads, upholstery, and insulation in wall cavities and under floors can all absorb vast amounts of moisture. Surfaces with vapor barriers can be very hard to dry if the moisture is able to seep under the surface. Vinyl floors in kitchens and bathrooms sometimes need to be torn up in order to let air flow freely to the wet areas.

Proper drying techniques, properly trained technicians and state-of-the-art and well-maintained equipment, combined with the use of EPA registered disinfectants and anti-microbials can transform your water-damaged areas to spaces that are environmentally safe and habitable within hours of the initial onset.

Procedures to Follow For General Mold and Mildew Prevention

Although there is no way to entirely eliminate all molds and their spores in the indoor environment, there are many ways to help control mold growth in your home or business.

    1. Stop any water intrusion from leaky pipes, non water-resistant building materials, rain water, etc.
    2. Clean fabrics often and keep them in well-ventilated areas.

    3. Reduce moisture with dehumidifiers and open windows or use air conditioners (in hot weather) with the goal of keeping the relative humidity in your home or business environment below 40%.

    4. Check regularly in problem areas such as bathrooms or laundry rooms for moldy–smelling odors. Disinfect with a 10% solution of sodium hypochlorite (bleach) mixing 1 1/4 to 1 1/2 cup of bleach to a gallon of water. A commercial disinfectant may also be used.

    5. Cover any dirt floors in basements with plastic in order to slow down the water vapor that comes through the soil.

    6. Make sure your kitchen and baths have ventilation fans and periodically check to make sure they are venting to the outside and that they have not become disconnected or blocked.

    7. Dryer vents can be a real problem. Make sure they are attached securely to the dryer and are venting to the outside. The vent duct can accumulate lint and should be cleaned at least once a year and checked for any holes that might leak air.

    8. Have your heating and cooling system in your home of business checked to make sure it is the correct size and that it is working properly to remove humidity. Also check your duct system for any air leaks.

How to Clean and Disinfect Contaminated Areas Without the Help of a Professional

As a general rule, if there has been a large amount of water damage and/or the mold growth covers more than 10 square feet (less than roughly a 3’x3’ patch), you probably will not be able to handle the job without professional intervention.

It is important to be very mindful that molds are always a source for health problems, especially when the airborne mold spores are inhaled in large quantities. Infants, children, immune-compromised patients, as well as pregnant women, the elderly and those with existing respiratory conditions are actually at a higher risk for adverse health effects.

Some symptoms that can occur from exposure to mold include

    Respiratory problems such as wheezing and asthma attacks.
    Nasal and sinus congestion.
    Dry, hacking cough.
    Burning, watery and red eyes.
    Nose or throat irritation causing sneezing fits or bloody noses.
    Skin irritations such as rashes or hives.
    Headaches, memory loss and mood changes.
    General aches and pains

Of Special Concern: Black Mold

Toxic black mold, Stachybotrys atra, a greenish-black, slimy mold resembling tar or black paint can cause much more serious health problems. In the case of the presence of more severe mold infestations, especially those with black mold, it would be better to call on a mold remediation professional. In any case, when exposed to mold, it is advisable, especially for sensitive people to wear tight fitting masks or respirators.

Because of the health-related issues and the unfamiliarity most consumers have with mold issues, ABC suggests calling a certified mold removal firm to eliminate any moderate to severe mold problems.

Be Prepared Before Cleaning

If you still wish to do the work yourself, make sure you wear gloves, a mask and some form of eye protection. Also make sure the working area is well-ventilated. Cleaning must be done before disinfection can begin.

Special Precautionary Measures to Take

    Make sure to exercise extreme caution when cleaning and disinfecting molds because mold spores will be released when the mold is disturbed.

    NEVER EVER MIX BLEACH WITH AMMONIA.The fumes can kill you.

    Be careful how and where you discard items that have been mold-contaminated. A professional trash handler may be needed for this task.

Cleaning Hard Surfaces

For hard surfaces, wash non-porous materials with a non-ammonia detergent and hot water. For rough surface materials, such as concrete, rub with a stiff brush.

After disinfecting all cleaned surfaces with a 10% bleach solution, let the solution stay on the surface for at least 10 minutes and then rinse with clear water and allow to dry. Please note: The bleach solution will kill the mold but not necessarily the spores.

Cleaning Porous Materials

Do not attempt to clean porous materials such as upholstered furniture, rugs, clothing, books, papers, etc., if the item has been wet for more than 48 hours.

If less than 48 hours has gone by, wet porous materials can be cleaned and disinfected with a pine-oil cleaner. After an item is dry, monitor it for several days for any new mold growth and odors. If mold does develop, discard the item.


A wet or contaminated area must be allowed to dry completely, at least 2 to 3 days before rebuilding, replacing or returning any items to the area.

Need More Advice?

Though ABC no longer performs water damage restoration or mold remediation, we would be happy to answer any questions you may have regarding these issues.

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