An Unknown Blackish-Greenish Substance

What is the substance in the pictures below? How would you describe it if you were telling a friend about the images? Have you ever encountered a property like this before? If you are a real estate agent, have you sold something similar? If you were planning to purchase a fixer-upper in the Sacramento Region (or elsewhere), would a blackish-greenish substance like this deter you from entering contract?

When appraisers come across issues like this, one would think we’d simply call the substance “mold”, but that’s not the case. The truth is that since a real estate appraiser is not a fungus or mold specialist, it’s important to not speak definitively about something that another licensed professional should be the expert on. Moreover, what if the substance was not just mold caused by excessive moisture damage, but “toxic mold”?

mold (16)


mold (2)

mold (5)

mold (10)

mold (11)

So what do appraisers say when encountering properties with an issue like this? Well, until we get clarification or a definitive pronouncement from a licensed mold professional, we simply describe the substance in words similar to “an unknown blackish-greenish substance”. When we do find out what the substance is, then we can better determine the impact on market value depending on cost-to-cure and the reaction in the marketplace to the existence of such a substance.

On Fannie Mae’s 1004 Appraisal Form, real estate appraisers are asked to identify any physical deficiencies or adverse conditions that might affect the livability, soundness or structural integrity of a property. The blackish-greenish substance in the photos above might potentially impact livability, right?

For further reading on mold, see the following links. You are welcome to suggest a link or share a story below too.  Thank you to an appraiser colleague who provided these images to me out of his work file.

Mold Links: An Unknown Blackish-Greenish Substance


  1. Conrad says

    Interesting insight into appraisal work. I would assume that this property has been unoccupied for some time, otherwise, I would be concerned for the health of the occupant(s). My wife and I once found a similar “unknown blackish-greenish substance” in a rental property on what was our first and last day of tenancy. No way were we staying in a place with what looked like mold all throughout the kitchen. The landlord wasn’t happy that we left and threatened to take us to small claims court after she got the place professionally cleaned. I agreed to go to court with her and bring along the photos that I took to document the “mold” and also inform the city of the situation. For some reason, she never pursued the suit!! Moral of the story, be careful around “mold” and always take pictures of it when you see it!

    • says

      Conrad, it’s amazing what types of situations people live in. Properties like the ones above though… well, you’d hope people weren’t actually residing there. I’ve seen some pretty terrible living situations before though.

      I would have left too. Good move on your part. I like the way you handled the whole situation too. Photos have a way of calming certain conversations.

  2. says

    Now THAT is horrible, just horrible!

    What a waste – something that can be avoided by paying attention – something too many renters and negligent owners don’t do.

    I have friends that live in La Honda (south of San Fran). Their roofer left it open and it rained and they had “blackish-green” stuff all over one end of the house, and kids with on-going respiratory problems.

    • says

      I know. It’s awful and bad on so many levels. What a sad story about your friend. I once met a home owner trying to buy a house they were renting. His daughter was having issues from the substance though. It was hard to believe that he was willing to buy the house. Affordability never trumps safety.


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