Effects on Wood-Plastic Composites

Wood-Plastic Composites, by Anatole A. Klyosov Copyright 2007 John Wiley Sons, Inc. 

Mold is a type of fungus that can weaken building materials including composite deck boards, make composites discolored or cover them with black, green, red, and other colored spots that can be very difficult to remove, and can make people sick with allergies, asthma, or respiratory problems, particularly in those who are already poor in health and/or have a pulmonary condition. Mold is one of the champions of survival on the Earth. Mold spores exist in astronomical numbers virtually everywhere around us. Air currents carry spores on decks, as well as onto all other surfaces. 

About 250 thousand mold spores would fit on the head of a pin. In order for mold spores to get awakened and to grow, they require moisture, warm temperature, oxygen, and a food source. On an outdoor deck, all these factors are very difficult to control. Mold can use dust and organic dirt as food source, and oxygen is around. Within hours of coming into contact with water, spores wake up and sprout germ tubes, which in turn develop a network of hyphae within days, sometimes hours. Hyphae extract nutrients from dust, dirt, wood particles, pollen, among others., and form thousands of new spores. Air currents pick them up and deliver elsewhere. Mold spores are ubiquities. They are fact of life on earth. In North America alone, there are more than 100,000 species of mold. 

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