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Asbestos in old rock wool batts?

mfleck | Posted in General Questions on

Hi all,

I have some 3-inch-thick Rock Wool Batts in my attic rafters that I plan to remove.  I have no idea how old they are, but most likely they are as old as the house (1930s…).  I’ve read that older Rock Wool may have had asbestos in it.

Is there a way to determine if my batts have asbestos in them?

Any recommendations on how to safely remove them myselff?

Thanks Everyone,

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  1. this_page_left_blank | | #1

    It's unlikely for rock wool batts to have asbestos, but the only way to know for sure is to send samples to an environmental lab for testing. I'd be far more worried about asbestos in the plaster, so if you're disturbing that I'd send them both for testing at the same time. Why are you removing the rock wool? If you want more R-value you can just blow stuff in over top of it.

    1. mfleck | | #2

      Hi Trevor,

      Thank you for your reply!

      I am removing the insulation because it is very old, compressed, and dirty. I am also in an existential debate about whether to vent or just dense pack cellulose in my rafters. Currently, the rock wall bats are installed flush against the underside of my roof. If I vent, I would definitely need to remove them.

  2. mfleck | | #3

    Anyone else heard of asbestos in Rock Wool Batts?

    Can anyone give advice on a safe way to remove them (they must be removed to create venting)?


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