Wood Floor Mystery #8: Is This Floor Fungus Among Us? Part 1

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3 1 21 Mystery8 Wood Floor Is It Mold820

If you read my stuff on the Wood Floor Business website, you know I am always looking for a good wood flooring mystery. The strange, weird, inexplicable stuff that puzzles even the savviest of floor pros. Well, recently one of my older articles, “What Causes Mysterious Black Spots in Wood Floors?” (published in the magazine’s February/March 2014 issue), received a comment that turned into a peculiar little mystery of its own. It started like this:

3 1 21 Stephen D Mold Comments

Two weeks later, I received an email, not from the commenter, but from someone else. The message was written with fear, concern and an intense sense of urgency. Attached was a series of hardwood flooring photos that, fair warning, turned my stomach a bit:

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Here’s what the email said:

Hi Stephen!

I'm so glad your post from 2014 was still active! I am hoping you can maybe give me some insight online! Last night when I was deep cleaning my closet with hardwood floors, I noticed two different areas of black spots. Keep in mind that we've been in our home for over 8 years. I do believe the floors were refinished before we moved in, but I'm not 100%. I am in contact with the previous owner, she may remember. I clean my closet fairly often, but not deep clean that often and these spots were on two totally different ends of the closet. It's pretty dark in there as well. I've also become very paranoid about mold because I have immune system issues. Anyway, my immediate thought was mold and now I'm super anxious, but there is no damage on the walls. There is also no plumbing nearby, anywhere nearby, that we know of at least. When you feel the area, it feels like the spots are raised, like dirt flecks. But I can't wipe them off. My husband took a good look and said he felt like whatever it was, was sealed over. When you try to scratch it off, it doesn't come off. I feel like I would've noticed this before, but it's also on the sides of the closet, furthest away from the light. Could you let me know your thoughts from my photos? I'm going to attach some of my photos here in this link. The first 4 are mine and the last 4 or 5 are the ones my husband took, which really show the texture. I don't care about what it looks like as it's in the closet, but if there is any chance it's mold, I will have an inspector come out to look!!

Thank you so much, and I'm so glad I found your post!!!


The serious and urgent part of this flooring dilemma is that mold can cause severe allergic reactions. It can trigger asthma attacks, lung infections, and even produce hypersensitivity pneumonitis, which closely resembles pneumonia. Tammy’s fears were valid, and with her compromised immune system, her home having any form of mold contamination could be harmful. 

This is where we come in, readers and floor pros who are now “C19OFI: COVID-19 Online Flooring Inspectors.” You must find solutions to wood flooring technical issues using only your wit, cunning, intellect, and industry experience during a time when inspecting a floor in person is off-limits. This is your assignment should you choose to accept it: What is going on with this floor? Leave your thoughts in the comments below.

FYI, there is enough information here to deduce a reasonable conclusion as to what is going on with this floor. Let’s see what you got, and we’ll post Part 2 with the answer soon. 

See more wood floor mysteries from Stephen Diggins:

Wood Floor Mystery #1: The Spreading Black Spots

Wood Floor Mystery #2: The Poly That Wouldn't Stick

Wood Floor Mystery #3: The Tale of the Half-Cupped Floors, Part 1

Wood Floor Mystery #4: How Did This Floor Get Like This?

Wood Floor Mystery #5: The Uniform Gaps

Wood Floor Mystery #6: The Case of the Crawling Finish

Wood Floor Mystery #7: The Case of the ‘Burned’ Floor

Wood Floor Mystery #9: A 'Sight' Inspection of a 'Disappearing' Gunstock Wood Floor, Part 1

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