Thread: Possible Expanded mica

Could anyone I.D. this type of insulation? Found this in a 1954 rach in the attic. See the attached picture. I think is Expanded mica, put not sure. anything you can tell me about it, would be a great. Thanks to all in advance.

I see you cite your location as "Lombard, Illinois".

Looks like expanded vermiculite.

Sold under brand name "Zonolite" and a multiple of other "branded" and "store branded" names. The West suburban plants packaged under many brand names and trade names, and for most of the home improvement, hardware, family department store brands, etc. many of which are long since out of business (the store chains).

Would also "fit" as to home age and the developments, materials cheaply available especially during the "energy crisis" of the 70s, etc. and what was MOSTLY used and sold in your local area to retrofit increased attic insulation in older homes in the western suburbs of Chicago.

West Chicago was a "popping" or expanding or "exfoliating" and packaging operation facitity for Libby, MT mined vermiculite on behalf of W.R. Grace & Co. IIRC it was processed in/nearer Downers Grove before that (this old brain tired thinking an EW road starting with an O and west of a NW road starting with an F). As I'm remembering both plants processed materials from the west that came in via rail road cars.

A qualified laboratory with special lighted microscopes can identify. Post-Burn analysis can determine definitavely.

I couldn't quickly find a reference to the even older plant I'm recalling, which I'm thinking was in or adjacent to present day Downers Grove; but I did find the ATSDR (Agency for Toxic Substances & Disease Registry - that's part of the U.S. CDC - Centers for Disease Control) listing for the West Chicago Plant.

Here is a link to same: ATSDR - Asbestos - Sites - Fact Sheet - West Chicago, IL

Vermiculite. Possibility that it contains asbestos. I would report it as a potential hazard and recommend a professional test it for asbestos. I would not enter the attic and I would definitely not conduct a blower door test.

"May contain TRACES of asbestos", sometimes less than 1%. I understand there were veins of asbestos running through the vermiculite deposits, so the concentrations of asbestos vary a great deal. Sampling is best left to experts, because finding none in one spot does not mean it is not in a spot 2 feet away.
The usual practice here is covering it with fiberglass batts and forgetting about it. Do not Disturb.

BTW, on the plus side, it is extremely non-flammable and makes an excellent fire-proofing for the attic floor.

Dear Colleague,
I want to sincerely thank all that responded to my thread. I really appreciate your efforts in helping me.
Happy Inspections…
Warmest regards from the Windy City