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Community and Q&A

Black insulation

thomasthecarpenter | Posted in General Questions on

My house was built in 1919 the exterior walls a clapboard the interior are clap board also.  For the most walls as far as I can tell are not insulated. When replacing a light switch and box I found black  insulation on some of the wiring. I recently opened a wall and found a lot of black insulation looks like settling caused me to think not all walls had it. It looks like cellulose but black. Is it asbestos ?  In the 1970s the walls were covered with1/4” drywall but no evidence of adding insulation at that time.

thomas the carpenter 

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  1. Expert Member
    Peter Engle | | #1

    Really can't tell from the photo. It does look like cellulose, but i am not familiar with cellulose that color, even in old houses. Others might be familiar with it. When in doubt, have it tested. Labs don't charge much to test a sample.

  2. Expert Member
    Dana Dorsett | | #2

    I've never seen asbestos that color.

    Take a sample outside and put a propane torch flame on it. If it burns it's probably cellulose. If it melts it could be fiberglass (unlikely if installed in 1919). If it glows orange but doesn't melt it could be rock wool, though I've never seen black rock wool either.

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