Types of Mold

Mold is a form of fungi that can be found all year round both indoors and outdoors. Outdoor mold thrives in soil, on plants and decaying matter. Indoor mold thrives on building materials such as; drywall, subflooring, wallpaper, drywall, cotton, wood and carpet.

Mold growth is encouraged by warm, humid conditions. Mold grows in dark and dim places, it can not grow under ultraviolet light. Mold has to have a warm environment and will not thrive in cold conditions. Mold also needs to have moisture, this usually comes from a water leak or humidity. Most molds can grow within 24 to 48 hours under the right conditions.

Most mold produce spores that travel through the air and spread easily. Mold that is found indoors has usually come from an outside source. Since it needs moisture to grow it is usually found in places where there has been water damage, high humidity or dampness.

There are four commonly found types of mold; cladosporium, penicillium, alternaria and aspergillus.


Cladosporium can be found in both outdoor and indoor environments. When cladosporium is found outdoors it is typically found on plants and organic matter. Indoors it can be found thriving on wallpaper, carpet and subflooring. Cladosporium very rarely cause human illnesses, but has been known to cause a few infections of the eye, skin, sinuses, and brain. It is also associated with allergies and asthma.


Penicillium is another type of mold that is found outdoors or indoors. Outside it can be found growing in soil, on decaying plant debris, in compost piles and on rotting fruit. Usually when found indoors penicillium is associated with water damage to plywood subflooring or drywall. It can however, be found growing on dried foods, cheeses, fruits, herbs, spices and cereals.


Alternaria is mostly an outdoor mold, but can be found indoors, usually if found indoors it originated outdoors.  Outdoors, alternaria thrives on vegetation such as; tomatoes, oranges and other fruits and vegetables. It is usually detected from spring to late fall and can be at its highest levels during dry and windy conditions.


Aspergillus is the most common of the four molds. It is both an indoor and outdoor mold.. It is found in oxygen rich environments, starchy foods such as; bread and potatoes and is also found in our bedding. Individuals with compromised immune systems may find aspergillus to be harmful to their health. Aspergillus has a wide array of sources. It may be present in ventilation systems, water systems, waste containers, and plants. Unlike most fungi, Aspergillus infections can also be passed from person to person.(source:  http://www.emlab.com/s/sampling/env-report-01-2010.html )

Any types of mold indoors should not be ignored. Call us today to schedule an appointment.


John has over 23 years of Indoor Air Quality experience. Some of the certifications he holds are: C.I.E Certified Indoor Environmentalist #00666 C.M.R Certified Mold Remediator #04124 Construction Engineering Technology Degree NADCA (National Air Duct Cleaning Association) Certifications: A.S.C.S Air System Cleaning Specialist # 9011357 C.V.I Certified Ventilation System Inspector # C203080526 V.S.M.R Ventilation System Mold Remediator # V303060706 Active Member of IAQA #1070 EPA Radon Certified
Contact Us

Use this form to send us an email and we will get back with you ASAP.

Not readable? Change text.