If you smell something musty it might be mold.

If your home has a persistent musty, earthy smell, like damp socks or old books , it could be more than just stale air…  It might be hidden mold.
Mold often starts growing behind walls, under floors, or in damp corners, and the smell is usually the first sign before you ever see it.
Don’t wait until it spreads — if you notice that odor, it’s time to call KMB to schedule a mold inspection. We’ll coordinate directly with your insurance company!