Identifying insulation in crawlspace

Hey everyone,

Anyone seen this set-up on the foundation walls on inside of crawlspace?

Thanks for the input.
InspectIT – 1634169252448|666x500

It looks like foam sprayed with cellulose to make it non combustible.

Thanks Marcel,

Have you seen this sprayed like this in your area?

I have, but I poked it with my awl to confirm it was foam and to find out the thickness of the foam.

Thanks again.

Looks more like a cellulose product from here.

Or this.

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Hey Michael,

It is only about 1 inch thick and looks blown in. It’s not the same texture as foam spray. It’s identical to the cellulose in the attic.


Do you have a moisture meter? What happens if you take a small bit off the ground, and dip it in water? Is it rejecting or retaining the water?

It looks like wet blown cellulose.

A foil faced or rigid foam is better because it doesn’t wick water, from the blocks…IMHO.


Agreed. And if so I’m highly skeptical that’s appropriate. Taking a core sample and smelling for mold feels appropriate.

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Remember to put the core back in its place.

The pest inspection area (4 inches of exposed CMU) along the top is missing?

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Hey everyone,
Thanks for all the input I really value your contributions. The crawlspace was in need of some TLC. Here are some other items that I am calling out.

Vapor barrier was not installed properly, it stopped at the footing and the dirt was exposed it also stopped 2 -3 inches short from the foundation wall.
The blown in cellulose was covering up portions of a deteriorating rim joist.

Again, thanks for all your help.


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Could the wet blown cellulose be contributing to the rim joist rot? Cellulose holds water.

Hey Bruce,

The set up looks very old and sketchy. The house is a rental and has been for about 8 years and it shows signs of being neglected. The area that has rotted is directly under the kitchen sink. There is evidence that the flooring and cabinetry has been replaced at some point.

Thanks for the input.

Hey all,

Another crawlspace same neighborhood…very odd smell coming out of this one. It is sealed and has a humidifier with a proper vapor barrier installed.

Many thanks

Well, that is some sort of fungal growth. Moisture may be from above (shower pan etc.) What was the RH in the crawl?

Also, I find it interesting the growth is around that seam. Moist air being drawn up thru the seam? Stack effect? Is the crawl ventilated?

That is directly under a downstairs bathroom. The crawl space is fully sealed and has a humidifier in it. There was a previous water leak before these residents moved in. I will call it out and recommend a certified mold specialist.


Hopefully, it is a dehumidifier. Plumbing leak makes sense, and apparently the water from the leak was not properly or adequately remediated.