Q We have noticed a mold odor in our house recently, but we see no evidence of mold. How can we find out where it's coming from?
A It's difficult. But some background information and dogged sleuthing using your nose can often lead you to the culprit. For mold to grow in your house it needs a moisture source, and that source might be outdoors, indoors or both.
Outdoor sources include:
• Leakage caused by clogged gutters might not be visible, but leaks can wet walls and attic spaces so that mold grows unseen.
• Leaks from improperly flashed windows, doors, decks and roofs. These defects also allow water to seep into wall cavities.
• If the ground around the house isn't sloped enough to drain surface water away, leakage can make the basement damp and increase humidity levels in the house.
Indoor moisture sources include:
• Plumbing leaks behind walls or under sinks.