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Are there any builders, architects, engineers, or homeowners interested in industrial hemp building?

Kristin Steen | Posted in Energy Efficiency and Durability on

Energy and bio-friendly materials significantly solve many issues I see here, and despite code/cost and other issues, it is a solution many are embracing…

Hempcrete, hemp fiber insulation, hemp particle board, carpets, furniture are all available and becoming more mainstream alternatives with immense positive experiences. Anybody have experiences or interest in this?

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Replies

  1. Malcolm Taylor | | #1

    Kristin,
    Have you ever worked with, or do you have any experience using this material?

  2. Kristin Steen | | #2

    Hi Malcom -

    I have ordered a bag of hempcrete, and am going to experiment myself, but I have not yet actually used it. The workshops have been too far from me ( Austrailia, California, etc) and I want to get one going here in NY - I have construction experience, am trained as an architect ( not licensed, but went to Pratt Sc of Arch a long time ago) ...

    So, the short answer - not yet! I do have a homeowner here that is interested, and am working up specs...

  3. Malcolm Taylor | | #3

    I hope you will fill us in on how you find working with it when your project goes ahead.

  4. User avatar
  5. Malcolm Taylor | | #5

    “You could smoke a telephone pole’s worth of our stuff and still not get high,”

    Now where's the fun in that?

  6. Alan B | | #6

    "“You could smoke a telephone pole’s worth of our stuff and still not get high,”

    Now where's the fun in that?"
    The gasoline used to transport the person to the "telephone pole" can be used to get high

  7. User avatar
    Hallie Bowie | | #7

    I just had a client ask me about hempcrete. Since it's R value is only 2.3 per inch it seems like a hard sell for cold climates. It would take another 5 1/2" of wall thickness to get up to an R40 compared to using cellulose. And until there is a North American source for the raw material I expect it is cost prohibitive too.

  8. Stuart Friedberg | | #8

    Hemp fiber is a great industrial fiber with a lot of uses and quite reasonable production costs, and much of the world has been using it all along. However, it's not a solution for every problem. If linen (flax bast) or sisal is appropriate, hemp is probably appropriate. Hempcrete has to compete with lots of other batt alternatives (e.g., blue jean batts, straw batts, ...) to the more conventional fiberglass, rock wool and blown cellulose.

  9. Pamela Bosch | | #9

    As of February 2019, the Highland Hemp House addition is receiving plaster on the interior walls. The hempcrete walls are 12" thick and enclose the 2 x 4" wood framing. In June of this year, I will be retrofitting the old part of the house with hempcrete. Located in Bellingham, WA, I am committed to sharing what I learn from utilizing hemp and lime as a monolithic wall system.

    1. Zephyr7 | | #10

      Do you happen to have a picture of any holes cored or drilled through this material so that we can see the internal structure? I’ve worked in old concrete buildings before and they used to use straw in the concrete for reinforcement. Im curious what the appearance of the hempcrete is I’ve never worked with it, or even heard of it before this forum.

      Bill

      1. Pamela Bosch | | #14

        Bill, the hempcrete is packed around the studs and finished with lime render. Walls are solid but not dense like concrete. Forms are packed by hand and tamped with a small mallet (unless they are sprayed, as in some European construction).

  10. Mike Kolder | | #11

    I'm interested in Hempcrete also and Highland Hemp House north of Seattle is in a cold climate. Maybe use hempcrete as breathable outside with double wall behind?

    1. Malcolm Taylor | | #12

      I guess Bellingham is cold compared to really warm places.

      1. Pamela Bosch | | #15

        There are quite a few hempcrete homes in Quebec, Russia, Poland, ...

        1. Malcolm Taylor | | #17

          I'm not disparaging Hempcrete, I was just pointing out Bellingham is probably best described as being in a temperate climate.

          Whatever its merits, I do think Hempcrete faces some pretty high hurdles to become more than a boutique method of construction. At present almost all building is done with industrial commodity products. Unless someone develops a way to supply hempcrete through lumberyards or some similar outlets, it simply won't see wide adoption. We may wish otherwise, but that's the (perhaps unpalatable) reality.

          1. Pamela Bosch | | #18

            That is absolutely true. No one can build with materials they don't have. I am well aware of what a challenge it is to get builders to change behaviors. But hemp was just legalized last year. The processing is not difficult--just no infrastructure investment. When you look at all of the advantages--no insect, rot, mold, landfill, VOCs, no China-sourced materials, no petrochemically derived materials, high carbon sequestration,... it becomes primitive thinking not to use it. I predict that, as the reality of not adapting to natural building hits harder, it will become more palatable. I hope it doesn't take too long.

  11. Pamela Bosch | | #13

    Green Building Community: I have built a 2400 sq ft hempcrete addition to my home in Bellingham, WA. I am now in the process of retrofitting another 1000 sq ft over my existing studs. This is happening now, August/September 2019. In October I will offer a class for architects, engineers, builders. Alex Sparrow of "The Hempcrete Book" will be here from the UK to instruct. Anyone interested in seeing this operation first-hand is welcome to contact me through Facebook (Highland Hemp House) or http://www.highlandhemphouse.com. If this method of building were to become a standard practice, we could actually accomplish the goals of "Green Building".

  12. Tim R | | #16

    I have specified light straw clay on several projects. It is used as an infill insulation, so compacted between studs using form work, like Hempcrete. It uses local clay, so minimal carbon footprint and typically straw from the exterior straw-bale walls.
    See ICC code appendix R, the members of the California Straw bale Association worked to get this code appendix so all can use it. It is easily adopted by local jurisdictions.
    The bottom of a light straw clay wall can be seen 2nd row from the bottom of the page of photos here http://simpleconstruct.net/gallery/fallgren-straw-bale-residence/

    Since the light straw clay wall is heavier than a conventional wall- additional top of wall connections are needed in higher seismic areas.
    https://codes.iccsafe.org/content/IRC2018/appendix-r-light-straw-clay-construction

  13. Pamela Bosch | | #19

    Clay and straw have advantages over hempcrete in some ways: cheap, local, ICC vetted. It is especially appropriate in hot, dry climates. Hempcrete is still dependant upon lime that must be calcined to about 900 C and needs to have a high Calcium content. Not as energy-intensive as concrete, but requires mining never-the-less. Some hempcrete builders use quite a bit of clay in the binder--Cannabrik in Spain, Morocco. Considering the chemical variations of concrete, binder technology could change considerably with some R&D. Calcium is not as common as clay but is the 5th most abundant element in the earth's crust.

  14. Tim R | | #20

    So, would it be possible to just order wood chips or bark and mix it with lime? Why is hemp the magic cellulose filler in this?

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