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Opinions on HempWool Batt Insulation

NICK KEENAN | Posted in Green Products and Materials on

I was reading about Hempwool, a batt insulation product made with hemp. See:

I like that it comes in rigid batts that you cut with a saw. One of the things I like is that it has no nasty dust or itchy fibers. In the videos guys are handling it without gloves, mask or eye protection.

Does anyone have experience?


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  1. SierraWayfarer | | #1

    We need a front page article. I googled just a little bit:
    In terms of quality and performance, hemp fiber stands out as probably the strongest and most durable fiber in nature. In addition to being 10 times stronger than wood fiber, hemp is four times stronger than cotton.

    Industrial hemp is lighter and less expensive to process than wood. One acre of hemp planted for 40 years has 400% more usable fiber than one acre of trees through their 40-year lifecycle. Hemp is the most efficient biomass source in the world. In less than 91 days, the plant can generate stalk to the stage where its fibers have contained their full CO2 content and are ready to be properly processed.

    More and more scientific publications underscore hemp’s other important characteristics: high absorption properties, IR and UV radiation protection capacity and natural low flammability. Further new, promising tests also indicate natural anti-bacterial properties of hemp fibers, believed to result from the alkaloids, cannabinoids and other bioactive or phenolic compounds.
    No telling what will be made out of this longest and strongest fiber in nature. If I was old money, I would be putting money into the ground floor of this!

  2. thegiz | | #2

    How good does it handle moisture, mold, mildew?

  3. SierraWayfarer | | #3

    Bump this one more time. It will be important. No telling what will be done with that cheapest, longest, strongest fiber. Maybe a better OSB for one thing.

  4. Expert Member
    Joshua Salinger | | #4

    We installed hempwool batts in an energy retrofit this past summer. I've included pics of it when it arrived and during the install. The client didn't want anything unnatural or containing chemical binders and they wanted a low carbon solution.

    Feeback from the team:

    -One still needs a suit; the threads were coarse enough to get in ones clothes, although it wasn't anything like the itchiness of fiberglass, just uncomfortable.
    -Definitely want a mask. There were still small particles that nobody wants to inhale
    -The fibers are really long. It made for tough cutting, similar to cutting mineral wool. A serrated knife while pressed between two pieces of plywood worked well.
    -One could get a nice angle on the cut, the cuts were clean
    -It doesn't tear easily. One can't just grab a handful and stuff it wherever.
    -It pressure fit really well into the framing cavities, no need to strap it up
    -The team liked not working with chemicals
    -It had a smell like straw that hung around for a few days but dissipated. The clients noticed it, but didn't mind the smell
    -A piece was left in the rain an elements since last August and it looks just like when it arrived except soggy. It seems pretty resilient.

    1. Expert Member
      BILL WICHERS | | #5

      How well did it recover from being wet? Did it dry out totally and quickly mineral-wool style, or did it dry out more slowly like a hay bale?

      This stuff used to be used for ropes on ships on the ocean, so I would expect it can get wet and dry out and be OK.


      1. Expert Member
        Joshua Salinger | | #6

        It's more akin to a hay bale than mineral wool. It's hydrophillic, but it seems more resilient than if one had a pile of cellulose out in the weather. I've found that the mineral wool can drain and dry out fairly quickly- it's not in that category...

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