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Tue Nov 27, 2012, 12:07 AM

New Zealand's first eco-friendly hempcrete house




Mr Flavall has returned from the United States to look into developing hemp-cropping in New Zealand to export to the US, has seen the potential, and is now keen to stay. His aim is to see 1200 acres (485ha) planted in Taranaki.

To make the building product, the internal part of the hemp stem is mixed with a lime-based binder. It continues to harden or petrify over time and lasts hundreds of years.

The result is a cheap, breathable, non-toxic product which is non-combustible, power-saving, soundproof - and has a negative carbon footprint, he says.

"It's a breathable wall yet air doesn't pass through."

One of the oldest crops known to man, hemp was used in the Great Wall of China, Roman viaducts and by Henry Ford in his first car.


http://www.stuff.co.nz/taranaki-daily-news/news/8000805/Hemp-sown-to-start-eco-house-business


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6 replies, 1804 views

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Arrow 6 replies Author Time Post
Reply New Zealand's first eco-friendly hempcrete house (Original post)
SHRED Nov 2012 OP
msongs Nov 2012 #1
freethought Nov 2012 #5
TlalocW Nov 2012 #2
niyad Nov 2012 #3
Nihil Nov 2012 #4
tama Nov 2012 #6

Response to SHRED (Original post)

Tue Nov 27, 2012, 12:12 AM

1. oh no, druggies will try to smoke their own houses. can't allow this! nt

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Response to msongs (Reply #1)

Tue Nov 27, 2012, 08:21 PM

5. It would be kinda hard to fit and entire house in bong.

Sorry, I just couldn't resist! ***sarcasm***

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Response to SHRED (Original post)

Tue Nov 27, 2012, 12:37 AM

2. This great and everything but...

There's a great confusion in this country that hemp = marijuana, and politicians exploit that to protect lumber interests, etc. so it doesn't help if you look like you're stoned off your ass in the official publicity picture of your new product.

TlalocW

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Response to SHRED (Original post)

Tue Nov 27, 2012, 12:48 AM

3. most interesting.

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Response to SHRED (Original post)

Tue Nov 27, 2012, 05:07 AM

4. Hmmm ...

Sounds nice on the first pass but ...

> To make the building product, the internal part of the hemp stem is mixed
> with a lime-based binder.

> and has a negative carbon footprint, he says.

Given that making lime is an energy-intensive activity, the rest of the process
would have to be seriously carbon negative to counteract it.

Not saying that it's not true, just somewhat questionable on anything other
than a "man working in a shed" scale ...


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Response to Nihil (Reply #4)

Fri Nov 30, 2012, 07:20 PM

6. Not expert

 

But calcium hydroxide can be acquired besides mining and slaking limestone with water (http://en.wikipedia.org/wiki/Slaked_lime), also by burning organic material, "ash-lime", which is energy-positive activity.

Quite likely some homey combination of wood ash and clay and water would work just as fine; the main thing is that the mixture needs to be alkaline enough for the chemical process.

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