We just bought a 21-year-old house. There is a strong chalky smell on the main floor. The basement, crawl space and upstairs bedrooms don't really smell. The worst is the garage. We air it out all day, but after closing windows and doors you can smell it again. We have asked a few people to tell us what they think they smell. Smoke, and masked smoke are always first on people's mind. But then they get confused and say they don't know what it is. There is carpeting and tiles. The garage is concrete. I don't think it's mold.

I am having the same problem in my house that I rent. I do have a problem with mice. I wonder if it could be related? This place has been a nightmare from day one. I pray that it isn't mold. Mice are bad enough.