[Greenbuilding] Cob as an alternative to spray foam sealant?

[natural building]

Steve, a minor correction: the Pumice comes from Mt. Garibaldi just  
north of Whistler, but still well within the 'local' range.  And  
Perlite - which Ann and Gord have experimented with - comes from  
Northern Oregon which I also think qualifies as within acceptable  
distance according to the Living Building Challenge criteria that  
allow light materials to be transported 1000 miles. Perlite is  
definitely light.

So I would suggest that the use of Perlite as a very natural and bio- 
degradable insulating material is considerably more preferable than  
oil-based foams which, in addition to having high embodied energy and  
being environmentally unfriendly, also renders the other materials  
onto which it is sprayed incapable of being re-used or recycled  
effectively.

Regards,
Steve Satow

www.naturalbuildingsite.net
naturalbuilding at shaw.ca

On 27-Jan-11, at 3:40 PM, Steve wrote:

>> I see a ".ca" in the "greengeek" edress so I going to ass-u-me that  
>> we're
>> talking a MooseLand locale ?
>
> Yep, I'm in Canada. Victoria, BC to be specific.. not too many moose
> around here that I've seen. :)
>
>> And if that assumption is accurate-  just wondering: Where in  
>> Canada are
>> there naturally-occurring perlite deposits ?
>> (And "no" I don't think that the "insulation" or "plastering  
>> supplies"
>> aisles at the nearest Home Despot qualify)
>
> It was Ann & Gord Baird of Eco-Sense (a well-known local cob house
> project) who renewed my interest in using natural volcanic stone as
> insulation. I checked again, and it was actually pumice, not perlite,
> that they used. My mistake. They sourced the pumice from a location
> right here on Vancouver Island.
>
>> ie Does it make Green sense to import a "natural" (if being
>> mined/pulverised/packaged/transported by massive machinery qualify  
>> it as
>> "natural")  thousands of kilometers and across international  
>> borders just so
>> that one can say that an insulation is "bio-degradable" ?
>
> If it wasn't available locally, then no it wouldn't be worth it, no
> matter how biodegradable it was.
>
>> Not only that, the resultant mixture likely wouldn't even provide the
>> minimum R-values for a wall as required by the Codes (assuming that  
>> the
>> cavity is standard 2x4 or 2x6  wood-frame construction) and would  
>> not seal
>> very well once it has dried and shrunk away from the framing.
>
> I was thinking it could be used as a later to provide an air seal, in
> addition to something like blown-in cellulose, or perhaps as a
> spray-on finish for strawbale, rather than filling wall cavities
> completely as the only insulation. I'm not a builder, and have only
> limited hands-on experience with either cob or clay plaster, so this
> is just a thought.
>
>> So I have to wonder: "Why bother ?"  ... knowing that here in  
>> Canada, a more
>> readily-available, lower environmental  impact, plentiful, "natural",
>> bio-degradable, blow-able "waste" material with about the same or  
>> better
>> insulation value as perlite (depending upon density of the form of  
>> perlite
>> used) exists.  (Sawdust, chopped straw or even chopped up recycled  
>> newsprint
>> etc  )
>
> It was just a thought; there are many different levels of "green
> building", ranging from light green barely-LEED-Silver designs to deep
> green natural building techniques such as cob, strawbale, etc. I was
> just thinking if the materials are available locally and would provide
> some benefit in place of oil-based spray foam, then it might be a way
> to make natural products more appealing to a conventional builder or
> client. Chopped straw might still be a bit of a leap for some people,
> something that went up like lightweight concrete probably wouldn't.
>
> -Steve
> -- 
> http://www.greengeek.ca
>
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