Are these dark spots on my wood floors mold?

Q: I have a house that was built in 1910 in Crescent City, FL that has heart pine floors throughout. These floors were professionally finished about 9 years ago with I believe a poly finish. I am only there once a week but noticed numerous dark spots on a small area of the floor that looked like blood spatter, that is the easiest way to describe it.

When I tried to clean it up I realized it was under the finish, and if I try to scrape the area it turns slightly gray.

The house sits off the ground about 12″ on a concrete wall with a sub-floor under the heart pine with a sandy soil as the base. What could cause spots like this to appear after over 100 years? There is nothing under this area that could heat it up and no water damage. I am wondering how I am going to spot strip the area and match the finish. Have you heard of anything like this before? Thanks for your help.

A: That it turns gray when you scrape it indicates to me it is a moisture stain. Perhaps some mold forming from excess moisture coming from beneath the floor? That’s my best guess.

Flooring turning dark

Related Q: Our laminated flooring, on a slab house, is turning dark. Is this mold? Could it be the wrong glue was used?

A: I would wonder if there is enough moisture to create an environment for mold. Why aren’t there other obvious signs of water issues such as curled edges? I would contact the manufacturer of the flooring.

Afraid the stains are mold

Related Q: I have found an apartment that I really want to move into. However, there are strange stains in the corners of some of the rooms and hallways. I am afraid this is mold and could be hazardous to my health. However, most people in my life have told me they are simply water or pet stains.

A: They probably are pet stains. Mold requires a warm, damp environment to grow and survive.

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