The complete source for building, designing, and remodeling green homes
Do you really want to delete the list, ?
This won't delete the articles you've saved, just the list.
This feature has been temporarily disabled during the beta site preview.
Replies
for thirty days
I have no data or links to provide (hopefully someone else here can do that) but from what research I've done (maybe five years ago?) is that it's not particullarly green, no. There's a lot of embodied energy in concrete, in portland cement in particular. There's lots of surface mining, hauling sorting, sifting, and firing. Then crushing and hauling some more. In the process of creating it, it also releases co2. That's in addition to the fuels burned to do all of the above. There is a legend that I've heard, a secret formula for concrete called "magnesite" that was used (and lost?) decades ago that actually absorbed co2 in its process.
I do like ICFs though. If you're finishing a below grade space, they're highly economical and provide an excellent R-value (like 21)
ICFs have a good R value? 10 is good? I guess in warmer places they work out OK. I agree that below grade they may be economical, etc, but that foam is sure not "green", IMO. I will be using them below grade, too, but not for green reasons. Before anyone uses them above grade, I hope they look at alternatives and whether or not they are appropriate for their area. Just my 2 cents. j
Neither concrete nor the EPS petrochemical foam that most ICFs are made of can be considered "green" or sustainable or low impact.
As noted, concrete - the second most used material on earth after water - has extremely high embodied energy and very high global warming contribution. EPS also has extremely high embodied energy and will never decompose (though insects and UV will destroy it).
ICFs may have modest R-value (not 21, generally 8 to 16 according to ORNL hotbox tests), but you lose almost all the dynamic mass value because the thermal mass is isolated from the conditioned space, and the foam has to be protected on two sides of the wall.
LCA of concrete, while resource intensive, has a lower embodied energy than that of steel. it also has less total GWP than steel.
http://www.inive.org/members_area/medias/pdf/Inive%5CIAQVEC2007%5CZhang_4.pdf
http://livebuilding.queensu.ca/files/Considering%20Sustainability.pdf
EPS can be recycled or reused, and as ODP/GWP of zero, or almost zero - but i wouldn't consider it green.
agree with above, though - i don't really understand losing the thermal storage capacity of concrete.