The summer heat and humidity is upon us and as we all know, it brings some issues that we need to address in an effort to keep our homes in good repair and to keep our indoor environment healthy. 

Most of us have seen the results of moisture or mold around the home.  As you may know, mold is alive and grows on wet or damp surfaces.  It is often gray or black, but it can also be white, orange or green.  It can grow both out in the open or it may be found in hidden places such as under carpets or in walls and attics.  Mold often smells musty.  Mildew is a common name for mold.

Mold reproduces by means of tiny spores that are invisible to the naked eye and float through outdoor and indoor air.  Mold spores can cause health problems by getting into your lungs.  Molds produce allergens, irritants and in some cases, potentially toxic substances.  Inhaling or touching mold or mold spores may cause allergic reactions in sensitive individuals.  Allergic reactions to mold are common and can be immediate or delayed.  It can also trigger asthma attacks.  Health reactions to mold can be severe in some people.   

The key to mold control is moisture control.  If mold is a problem in your home, you should clean up the mold promptly and fix the water problem. Sometimes, locating the source of moisture can be a challenge.  Typical places that water can seep into your house from the outside is through the foundation or small gaps around windows and doors.  It can also come from inside your house from a leaking water pipe, toilet, shower or bathtub.  It is important to dry water-damaged areas and items within 24-48 hours to prevent mold growth.  High indoor humidity caused by normal activities of everyday living such as showering, cooking and drying clothes can result in mold, mildew or musty odors.  Indoor humidity levels between 30% and 50% are ideal.   

Measures that you can take to reduce indoor humidity include the following:

If you have a crawlspace under your house, the dirt floor should be covered with plastic (vapor barrier) to prevent moisture from the soil increasing humidity levels in your home. If there is standing water or the soil is wet, dry it out with fans before covering the floor. Use ventilation fans that are vented directly to the outside in kitchens and baths to control moisture.   In some cases the vent fan may have been installed to vent into the attic or become disconnected or blocked. Your clothes dryer should be vented directly to the outside. Make sure the vent duct is attached securely to the dryer and is clear of obstructions such as lint.  If it is damaged replace it with a metal duct. The vent duct should be cleaned at least once a year. Keep air conditioning drip pans clean and the drain lines unobstructed and flowing properly. Ask a heating and cooling contractor to check your heating and cooling system to make sure it is sized and operating properly to remove humidity. If your system is too big or the airflow incorrect your air conditioner will not remove humidity like it should. Also, ask the contractor to check your duct system for air leaks, proper size and air flow to each room.

You may suspect hidden mold if a building smells moldy, but you cannot see the source or if you know there has been water damage or residents are reporting health problems.  Locations of possible hidden mold can be the back side of dry wall, wallpaper, paneling, the top side of ceiling tiles, the underside of carpets and pads, inside ductwork, etc. 

If you have questions regarding mitigation, contact your local University of Missouri Extension office for guide sheets on how to safely clean up mold and mildew.