Mold is found both indoors and outdoors. Mold can enter a home through open doorways, windows, vents, and heating and air conditioning systems. Mold in the air can also attach itself to clothing, shoes, bags, and pets can and be carried indoors.
Mold will grow anywhere there is moisture and a food source, such as around roof leaks, windows, or pipes, or where there has been flooding. Paper products, cardboard, ceiling tiles, and wood products are excellent food sources for mold. Mold can also grow in dust, paints, wallpaper, insulation, drywall, carpet, fabric, and upholstery.