I just purchased an older home with about 2-3 inches of Vermiculite
insulation in the attic. I would like to increase the amount of
insulation in the attic eventually. I also understand that Vermiculite
insulation can be dangerous, and may contain asbestos.
What would be the best approach to adding insulation to the attice.
Should I add more Vermiculite? Is it still sold? Should I remove, or
have the Vermiculite removed, then add fiberglass batts??? (I have a
double cartridge mask that I wear anytime I need to go in this attic.)
Any thoughts you have will be appreciated. I will be speaking to
insulation contractors eventally, but I'd like to enter the
conversation with some background information... Thanks!!!
Vermiculite contains asbestos. Do not, repeat, do not try remove it yourself.
You'll just spread the bad stuff all over the place, everywhere around the house.
Get a good asbestos removal company to assess the situation. This is not the
situation where you want save some bucks and DIY.
As I understand it all vermiculite contains asbestos but in some it is
far too small an amount to worry about. I also understand that leaving it
alone is OK, but you should have it removed professionally or have it
checked for content before trying to do it yourself.
No, vermiculite is a mineral. During mfg, the mineral
particles are "exploded" to create the insulation mtl.
Turns out some of the firms making/selling the stuff
*knew* all along that the feedstocks contained asbestos!
Since nobody really seems to know much about this but
everyone's posting what they *think* they know, I'll do so as
well. The asbestos issue with vermiculite is ("as far as I
know") a problem with naturally occuring contamination of the
vermiculite processed at the W.R. Grace mines in Libby, MT.
This stuff was shipped all over the country as insulation
(typically under the brand "Zonolite") and soil additive for
nursuries. The EPA recommends simply not disturbing any
suspect asbestos in residential settings-- you'll cause more
problems trying to remove it than to just cover and let it
sit. You're better off just insulating over it and forgetting
Occupational exposure to asbestos is a hazard. My grandfather
died of lung disease related to his work in shipyards
surrounded by asbestos. But the small amounts one would
encounter in a residential setting (outside of Libby, MT, and
other factory sites where apparently it was spread around
people's yards and kids played in piles of tainted vermiculite
processing spoils) aren't worth worrying about. If they were,
we'd have a nation-wide epidemic of mesothelioma. But it
remains quite rare, despite the mountains of asbestos in
homes, schools, and workplaces around the country.
Info on Libby and vermiculite:
Info on cleanup of processing site in Minneapolis:
Info on asbestos-inducted mesothelioma is here:
Hope this helps-- the point is jus leave it alone and insulate
your attic over it with something modern and more effective.
2" of vermiculite is about R-0 today, after it's settled.
Thanks for the excellent information...
There are some empty Vermiculite bags in the attic... I will pull one
out, and try to see where the stuff originated from... I will also
have insulation put over the existing vermiculite.
Doesn't much matter where it came from, for two reasons. First of all, you
may as well leave it in place and insulate over it. And second, you probably
know that you should wear a filter mask even if the stuff contains NO
asbestos. It's still very dusty stuff to work with.
Vermiculite is a mineral, it is mined and has
nothing to do with cellulose. Vermiculite does
not necessarily contain asbestos; the major
source of vermiculite contaminated with asbestos
is from mines in Libby Montana.
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