Expert: Dave Coil - 5/7/2004

Question
Hi Dave,

I have round black spots on my unfinished oak floor that range from 1/4 inch to an inch in diameter. I started with just several of them, and now they have spread out from underneath my dining room table and are scattered across the floor all the way to the walls. A woodworker told me that they may be a mold or a fungus. Would you concur? What kind of mold or fungus would attack oak floor boards, and have you any suggestions for dealing with the situation? A couple of years ago I removed the carpet installied by the previous owners, and have been waiting to do some other renovations before finishing the floor. Now I am worried that while I am busy with other projects, these spots will spread everywhere! I could send a digital photo if that would help. The only other variable I can think of is that I have a dog. He's   not a big drooler, but could saliva cause this?

Thank you!

Regards,
Gail  

Answer
Oak flooring will stain with water.  If the surface for edges were not properly sealed..water will find a way in.   Mopping can do it.   Spill can do it.   I have a similar stain at my dishwasher.  The only way I know of to get it out....Boric Acid.   I have no idea where you might get some.  It has been many years since I had to buy any.  Clorox is a possibility but its trial and error for that.  The worst/best solution is to sand the surface off and then "steam" the wood until you get enough rise in the grain to remove it.   I would hesitate to call it mould...but it could be.