Building Green: Chapter 8 – Cob and Other Earth Mixes

Papercrete Mixer and Pump

August 1st, 2009 by Seldom

This seems to be a good hemcrete mixer.

And here’s papercrete being pumped.

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Telephone Pole Spliff: CNBC Weighs in on Industrial Hemp

May 12th, 2009 by Clarke

We are presently using a hemp insulation product (Tradical Hemcrete) in our Nauhaus prototype project , but we can’t currently manaufacture hemp-based insulation in the US.  Luckily, this  issue is getting more and more media play. Here’s a very positive little piece from CNBC.

Industrial Hemp fun facts:

  1. The US is the only country in the world in which industrial hemp is illegal to grow.
  2. Industrial hemp is the only plant in the US that is illegal to grow, but legal to buy. We are huge consumers of a variety of legal hemp products.
  3. Industrial hemp is not a drug. Quote from the video: “You’d have to smoke a joint the  size of a telephone pole to experience any effect.”
  4. ______________________________________________________________

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Videos of a Strawbale and Adobe Houses in an Earthquake

April 12th, 2009 by Seldom

This video shows a strawbale building built by PAKSBAB being subjected to a simulated earthquake. Background by Darcy Donovan:

On October 8, 2005, the northern mountainous region of Pakistan was struck by a 7.6 magnitude earthquake which killed more than 100,000 people and rendered more than 3 million homeless due to unsafe building construction. Modern conventional building methods are largely unaffordable for the poor in developing countries such as Pakistan. As a solution, Pakistan Straw Bale and Appropriate Building (PAKSBAB) is developing unique earthquake-resistant straw bale building methods that are affordable, energy efficient, and utilize locally-resourced renewable materials.

The PAKSBAB gallery shows how they are constructed: paksbab.org

From Buildinggreen.com:

The quake-resistant buildings designed by PAKSBAB (Pakistan Straw Bale and Appropriate Building) are intended to be affordable, energy efficient, and locally built with readily available materials.

Bamboo rods and nylon fishing net act as the reinforcement and tie-down system; the netting is wrapped under a soil-cement-encased gravel-bag foundation (made with old vegetable sacks), up the load-bearing baled-straw wall, and attached to the wooden top plates. The wall-tall bamboo, which also engages both the foundation and the top plate, is attached upright in opposing pairs on either side of the wall at frequent spacings and ‘sewn’ together through the bales, providing flexible resistance to out-of-plane forces. The whole assembly is covered with earthen plaster. The roofing is light corrugated steel. The hand-made structural straw bales — there are no posts or other bearing members — are smaller than those produced by automatic balers, which are rare in developing countries.

Here are some videos of adobe buildings being shaken:

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Legalize Hemp?

March 27th, 2009 by garnet

Hemp is not Pot

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Effect of Moisture on Straw Bale Wall R Value

February 23rd, 2009 by Seldom

This explanation of the wide range of R values found for straw bales makes sense to me. Dry bales have a higher R value than wet ones because a lot of the heat transferred to a straw bale with a high moisture content is used to evaporate the moisture.

:: Straw Bale: What’s the R Value

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TGB Music Night

February 17th, 2009 by admin

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Hemp History 101

February 8th, 2009 by Seldom

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Hemcrete Discussion

January 28th, 2009 by admin

I think we should start using the blog to discuss certain issues that we are considering. It seems an easierway to keep track of the discussion than email threads. Let’s try it with our topic of the day: Hemcrete

1. I’m wondering if we should consider HC with the interior masonry columns? The columns cold be used to attache interior formwork and the HC could seamlessly go in front of them. The cool thing about this is that, unlike with double stick framing or SIPS, we wouldn’t need any more wood, either framing or sheathing, for the structure, therefore making the masonry column a less expensive upgrade in this constext than the others. I wonder if it would really cost any more than the structural systems that they are typically using with Hemcrete.

2. Matt said today that he’s been using scrap plywood from window openings, etc. as subfloor for attics.  We figured we would need 30 sheets of 1/2 ply or OSB as forms for the JJJ ranch. What about using the forms for subfloor in the attic (Jeff may have already mentioned this possibility to me. Based on Jeff’s loft subfloor estimate in the spreadsheet, that would take about 12 sheets, but we might want to double them up (laid in opossite directions) for more strength. That’s 2/3 of the formwork right there.


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