Crawl space stuff???

[Scott A. Figert]

Anybody know what this is? I've seen it many times but do not know what it is. It's a hard white crystal substance on the bottom & sides up about 3" on the floor joist.

[cbuell]

It almost looks like it flooded that high----is that a possibility? I had one a while back with seaweed hanging down from the insulation.

[Scott A. Figert]

This house has 5 different crawl spaces, 3 is all I could find access to. The 2 others had vapor barrier in this one did not. And this is the only 1 found with this on. Botttoms of joist are 8-10" above ground, impossible to flood that high at this location. Should have taken samples and sent to ProLab just so I would know what it is.

[David P. Valley]

With the line being that level, I would imagine it was a flood line.

Whatever it is, it doesn't appear to be a defect in the wood members.

[Scott A. Figert]

I don't think it is a defect either. There were no holes (insect infestation) or rot on the joist. Just the hard white crystal like deposits on the bottom & sides.

[Scott A. Figert]

The 3rd picture is where I wiped the side off to check for any holes & rot.

[bkelly1]

What was the venitlation like?

[Scott A. Figert]

Ventilation was minimal. 4 vents for the original 1800 sq. ft. house. But as I said this 1 of 3 sections of crawl I could get to is the only one that had it.

[Joseph Hagarty, CMI]

How old is the Home?

[cbuell]

Is it possible that it filled up during construction? Or major plumbing leak? Sure looks like a flood line.

[dbush]

Saw this once before on a repo home. Had an electric sump pump in the crawl space; however, the bank being the intelligent people that they are, decided to save some money by shutting off the electricity. This was able to let the crawl space continue to fill up with spring time ground water. But they were able to save the monthly electric bill.

[David A. Andersen]

Looks like mold to me (though I never use that word)!

It looks like the result of air stratification in the CS. The line of delineation is where the warmer air is stuck up between the floor joists. The warmer air is probably not conducive to this type of mold.

[Scott A. Figert]

House is a 1959. I looked under 3/4 of the house, could not find last access, this was in only 1 of the sections I looked in. It was also the only 1 w/o vapor barrier. Possitive there was no way to flood this high as all the sections were interconnected by way of water would be able to go over the dividing walls, the water would have been level in all crawls. O/S grnd level is 8" below the joist and in flat country, Whole county would of had to go under water. Next time I see this I'm going to get a sample off to ProLab.

[Bruce A. King]

Maybe someone removed the floor insulation. The "mold" was under the insulated line.

[Scott A. Figert]

No other signs of old insulation.