Mold is everywhere. It’s a type of fungus that grows from tiny spores that float in the air. It can grow almost anywhere that spores land and find moisture and a comfortable temperature, between 40 and 100 degrees F. Typically that includes about every damp place in your home.
You can easily spot the most visible type of mold, called mildew, which begins as tiny, usually black spots but often grows into larger colonies. It’s the black stuff you see in the grout lines in your shower, on damp walls, and outdoors on the surfaces of deck boards and painted siding, especially in damp and shady areas. A mildewed surface is often difficult to distinguish from a dirty one. To test for mildew, simply dab a few drops of household bleach on the blackened area. If it lightens after one to two minutes, you have mildew. If the area remains dark, you probably have dirt.
Mildew is a surface type of mold that won’t damage your home’s structure. But other types of mold cause rot. Probe the suspect area with a screwdriver or other sharp tool (Photo 3). If the wood is soft or crumbles, the fungi have taken hold and rot has begun.
If you have a high concentration of mold, you may smell it. If you detect the typical musty odor, check for mold on damp carpets, damp walls, damp crawlspaces and wet wood under your floors, wet roof sheathing and other damp areas. Clean up these infestations right away before they get worse, and see the following photos for prevention measures.