Crystals in the dirt

These pictures are from underneath a raised structural floor. No vapor barrier (pretty typical here in Colorado.) White crystals are everywhere. It is not snow, ice or meth. Mold? Salts? The humidistat and fan was installed and functioning. Perimeter drains to the sump and pump functioning as intended. No oder.

Thoughts, comments, opinions?

Efflorescence… It’s an indication of moisture intrusion. The humidistat and fan are probably doing a good job of getting rid of the moisture as it wicks in, but as it evaporates, it leaves the solids.

Termite treatment product. Probably something like Timbor which is boric acid crystals that are disolved in water and sprayed. sometimes the crystals do not disolve all the way and you can see them if you look close. Had the exact same thing happen to me a few months ago that threw me for a loop. Pictures looked exactly the same.

Ask if there was a recent treatment done, bet you will find your answer there. It is often required that a contractor do or have a preventative treatment done before releasing the property to ensure that any building materials left do not attract termites. See if there is an NPMA 99A/B form anywhere in the records.

See the picture I posted here.

A good answer, Scott, but the floor framing is steel. Maybe the whole house structur is steel. Is it a legal requirement to do a termite treatment no matter what the structure?

Thanks everyone! This board is so helpful! I went with the Efflorescence. We don’t have a lot of termite issues in this part of Colorado. I have some of these “crystals” under my floor, just not to this degree, and I know this house has never been treated for termites.

It doesn’t look like efflorescence to me, Tom. Efflorescence around here isn’t typically light, fluffy and translucent like that… at least none I’ve seen, and we’re working the same area. I’ve seen it up to about 1/8" thick and it had the consistency of baking powder or slightly course gypsom plaster. That stuff looks like cotton candy. From the picture, I wouldn’t call it efflorescence.

Cotton Candy! Are there any evidence of carnies living in the crawlspace?

Damn! Once they set in, no way to get rid of them. Time to move.


Kenton - so, what do you think it might be? Are you on the termite bandwagon or maybe mold? I would love to get to the bottom of this for future inspections. When are you coming to our Denver chapter NACHI meetings? We have one in about 2 hours!

Hey you other guys - quit clowning around!!!:smiley:

Do you have any other pictures of this by any chance? What was the relative humidity in the space? Was there an indication there was a high mineral content in the soil, like crushed limestone or anything?

It’s a pretty interesting find. Seems strange that it looks like is is completely covering the ground. I’m still thinking it could be a termite treatment. Possible you have a transplant builder that is just used to doing things that way and did it out of habit.

Hey Scott, here are a couple more pictures, although they don’t really reveal much else.

When I took the actual, large, photos to the Denver chapter NACHI last week, two of the top area inspectors looked at them (separately, so they did not influence each other) and immediately said “Efflorescence.”

I spoke with Kenton Shepard on Sunday, and he is still not convinced. “No way of knowing for sure unless it is tested.” Which I agree with but will not upset these people. I will carry sample jars with me and get it next time. I have seen it before, just not to this extent. Which is another reason I am not buying your termite treatment theory. When I have seen it before it was more spotty, not entire ground cover. Also notice in one of the first pictures, it does NOT cover the sewer pipe. Very careful treatment appliers?

I don’t know. I’m just going to wait until I see it again (I thought I had it in my crawl space, but I don’t.) Get it tested somehow. I am still leaning to efflorescence, but you and Kenton are tough to convince!

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Hey Tom…

Glad to hear that you took the pictures to your local chapter. That’s one of the reason why we have chapters in the first place. You are right and I looked at the sewer pipe and it does not sdeem to be covered. I learned to carry small plastic wide mouth jars in my inspection tool bag after my little strange encounter with a similar substance. It is probably likely that it is efflorescence after rereading the background information that you gave and looking at the pictures really really close. Initially I wouldn’t think that efflorescence would cover an area that big so evenly. That is why I thought it was probably some sort of sprayed on termite treatment. We encounter that alot up here in Pennsylvania.

Glad to see you are using all the resources available to you and keeping an open mind.