Inspected another duplex. There was moisture (puddles on the vapor barrier) in both crawl spaces. Only one crawl space foundation wall had this stuff though. I scraped some off and it was very “hairy” and fibery looking. No moisture staining of any kind. Has anybody ever seen this?
A heavy concentration of efflorescence.
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Roger that!
I don’t know what it is, but that does not look like any type of efflorescence I have seen before. Never come across fibrous material like that. Efflorescence on concrete like one of the photos is more powdery.
Maybe it is Borax.
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looks like heavy efflorescence from Ohio…I bet it tasted salty…
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What is pictured depends on whom you ask 
Impossible to know 100% without testing but one could take a guess. Could be efflorescence could be additives such as kryton. If you want to know if it’s mold, spray it with some water, efflorescence usually dissolves easily but white mold does not.
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Lick test!
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A heavy concentration of efflorescence most likely near an exterior downspout or some other water source, poor drainage around the foundation. the white powder on your flashlight looks like efflorescence.
I found a picture that resembles that pretty well. It’s called crystalline efflorescence, which is different than the powdery stuff I am used to.
Efflorescence can look very similar to white mold growth. It occurs when moisture moves through concrete (or other types of masonry) and pulls minerals along with the water. As the water evaporates at the surface, the salts and minerals are left behind, leaving a crystalline growth.
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Agreed, looks like efflorescence.
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because of an extreme amount of exterior water along the foundation.
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Yes, I am more familiar with seeing it on brick which looks different. Not many crawls around here. And when foundations are waterproofed properly, you don’t see that in basements.
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Thanks a lot guys!!
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Efflorescence on the concrete.
Efflorescence is the white powdery substance on the surfaces of unsealed untreated concrete.
I have seen what appears to be the same as your picture. IMO it is in fact efflorescence. Now, what is causing the heavy amount has me curious!
I guess you did not read the entire thread.
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I did. I always do.
Well, the answer is in the thread.
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