Icynene vs straw is a good example of the difficulty in making
appropriate choices of "green" materials.
While I don't think that spray foams should be used in new
construction, stuffing straw into existing walls for a
retrofit/upgrade is not a sensible option and with a limited wall
cavity Icynene may be the best alternative for renovation. Even for
new construction, straw bales - with their low R-value per inch
(—1.45, about the same as lumber) may not be the best choice.
Besides having no global warming or ozone-depleting installation
by-products, Icynene has only a little more embodied energy per cubic
foot than fiberglass (not that I would recommend fiberglass for
anything), typically less installed embodied energy (since framing
bays are not generally completely filled) and better efficiency
payback.
Best use of remaining fossil energy and petrochemicals? Not so
simple to discern. --- On Thu, 12/11/08, Michelle Smith
Mullarkey <[log in to unmask]>
wrote:
Point taken. I admittedly was thinking
of products like Icynene vs. straw, but it seems fossil fuels really
are part of our entire world. On 12/10/2008 6:21 PM, Robert
Riversong wrote:
Fossil fuel is still used to
manufacture and transport the majority of green building
products (not natural building products such as
straw bales)...
I'm afraid that fossil
fuels are used for the production of most straw and since
some of it is coming from Canada, there's also
transportation costs. "Natural" building materials are not
necessarily immune from the environmental costs of other
materials.
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