Introduction to Mold

 This information is for people who have mold problems in their homes.  It presents the health concerns associated with mold exposure and advice on finding and removing mold contaminations.

 If you feel that your house has been contaminated with mold growth and you rent from a landlord, you need to inform your landlord immediately.  Your health could be at risk. 

 What is Mold?

Molds are fungi.  Molds grow throughout the natural and built environment.  Tiny particles of mold are present in indoor and outdoor air.  In nature, molds help break down dead materials and can be found growing on soil, foods, plant matter and other items.  Molds produce microscopic cells called “spores” which are very tiny and spread easily through the air.  Live spores act like seeds, forming new mold growths (colonies) when they find the right conditions.

 What does mold need to grow?

Mold only needs a few simple things to grow and multiply:

• Moisture
• Nutrients
• Suitable place to grow

 Controlling excess moisture is the key to preventing and stopping indoor mold growth. 

Health Effects

Mold can affect the health of people who are exposed to it.  People are mainly exposed to mold by breathing spores or other tiny fragments.  People can also be exposed through skin contact with  mold contaminants (for example, by touching moldy surfaces) and by swallowing it.

 What symptoms might I see?

The most common health problems caused by indoor mold are allergy symptoms.  Although other and more serious problems can occur, people exposed to mold commonly report problems such as: 

• Nasal and sinus congestion
• Cough
• Respiratory problems, such as wheeze/breathing difficulties
• Sore throat
• Skin and eye irritation
• Upper respiratory infections (including sinus)
• Nose and throat irritation
• Aches and pains
• Possible fever

 Detection of Mold

How can I tell I have mold in my house?  If you can see mold, or if there is an earthy or musty odor, you can assume you have a mold problem.  Allergic individuals may experience the symptoms listed above.  Look for previous water damage.  Visible mold growth is found underneath materials where water has damaged surfaces, or behind walls.  Look for discoloration and leaching room plaster.

 Identify and Fix the Moisture Problem

The most important step in solving a mold problem is to identify and correct the moisture sources that allowed the growth in the first place.  Common indoor moisture sources include: 

• Flooding
• Condensation (caused by indoor humidity that is too high or surfaces that are too cold)
• Roof leaks
• Plumbing leaks
• Humidifier use
• Inadequate venting of kitchen and bath humidity
• Improper venting of combustion appliances
• Failure to vent clothes dryer exhaust outdoors (including electric dryers)
• House plants – watering them can generate large amounts of moisture

Removal of Moldy Materials

• Wear gloves when handling moldy materials
• Remove porous materials (examples: ceiling tiles, sheetrock, carpeting, wood products)
• Carpeting can be a difficult problem – drying does not remove the dead spores.  If there is heavy mold, disposal of the carpet should be considered
• Bag and discard the moldy substances
• Allow the area to dry 2 or 3 days
• If flooded, remove all sheetrock to at least 12 inches above the high water mark.  Visually inspect the wall interior and remove any other intrusive molds. (This step may have to be carried out by a licensed contractor).

 CAUTION:  Spores are easily released when moldy material is dried out.

Soap Cleanup

Before disinfecting contaminated areas, clean the areas to remove as much of the mold (and food it is growing on) as possible. 

• Wear gloves when doing this cleanup
• Use a non-ammonia soap or detergent, or a commercial cleaner, in hot water, and scrub the entire area affected by the mold
• Use a stiff brush or cleaning pad on block walls or uneven surfaces
• Rinse clean with water.  A wet/dry vacuum is handy for this.

 Disinfect Surfaces

• Wear gloves when using disinfectants
• After thorough cleaning and rinsing, disinfect the area with a solution of 10% household bleach (e.g., 1 ½ cup of bleach per gallon of water).  Using bleach straight from the bottle will not be more effective
• Never mix bleach with Ammonia – the fumes are toxic
• When disinfecting a large structure, make sure the entire surface is wetted (floors, joists and posts)
• Avoid excessive amounts of runoff or standing bleach
• Let disinfecting areas dry naturally overnight – this is important to kill all of the mold.

 CAUTION:  Bleach fumes can irritate the eyes, nose, and throat, and damage clothing and shoes.  Make sure the working area is ventilated well.

 Moisture Control

There are many ways to control moisture in your home: 

• Fix leaks and seepage.  If water is entering the house from the outside, your options range from simple landscaping to extensive excavation and waterproofing.  (The ground should slope away from the house.)  Water in the basement can result from the lack of gutters or a water flow toward the house.  Water leaks in pipes or around tubs and sinks can provide a place for biological pollutants to grow.
• Put a plastic cover over dirt in crawlspaces to prevent moisture from coming in from the ground.  Be sure crawlspaces are well-ventilated.
• Use exhaust fans in bathrooms and kitchens to remove moisture to the outside (not into the attic).  Vent your clothes dryer to the outside.
• Turn off certain appliances (such as humidifiers or kerosene heaters) if you notice moisture on windows and other surfaces.
• Use dehumidifiers and air conditioners, especially in hot, humid climates, to reduce moisture in the air, but be sure that the appliances don’t become sources of biological pollutants.
• Raise the temperature of cold surfaces were moisture condenses.  Use insulation or storm windows.  (A storm window installed on the inside works better than one installed on the outside.)  Open doors between rooms (especially doors to closets which may be colder than the rooms) to increase circulation.  Circulation carries heat to the cold surfaces.  Increase air circulation by using fans and by moving furniture from wall corners to promote air and heat circulation.  Be sure that your house has a source of fresh air and can expel excessive moisture from the home.
• Pay special attention to carpet on concrete floors.  Carpet can absorb moisture and serve as a place for biological pollutants to grow.  Use area rugs which can be taken up and washed often.  In certain climates, if carpet is to be installed over a concrete floor, it may be necessary to use a vapor barrier (plastic sheeting) over the concrete and cover that with sub-flooring (insulation covered with plywood) to a moisture problem.

Remain on MOLD ALERT

Continue looking for signs of moisture problems or return of mold growth.  Be particularly alert to moisture in areas of past growth.  If mold returns, repeat cleaning steps and consider using a stronger solution to disinfect the area again.