[Strawbale] Cement vs. clay (was "trashcrete")

[Andrew deGruchy]

Dear Sigi and CO2 Savers,

I believe our Brick and Mortar Calculator will be on-line by week's end for
anyone who wants to use it. Since I have the calculations from the Portland
Cement Association on exactly what their CO2 emission is in the production
of Portland cement and I already have the CO2 emission from St. Astier along
with the associated shipping and trucking fuel emissions from NY to
California, I am posting what the approximate C02 savings will be if the NHL
material is used for construction, (just about anywhere USA), over using
similar mixes which use Portland Cement as the binder. I would agree that
what is optimal is not to have anything shipped or trucked and use  only
local materials. In the interim this is an option to consider. It is funny
how the more things "advance" to what is optimally good for the earth, the
more we are going back to how buildings were built for the majority all of
history. Local materials were, for the majority, obtained from within 5
miles of the construction site. History repeats itself....and it looks like
we will be bound to re-live it if we keep getting closer to the mark of
optimal green.

Andy deGruchy

p.s.- Sigi, five minutes from your house we have been working on The
Highlands Barn for the Pennsylvania Historic and Museum Commission for the
last two months doing repointing and repairs. We used a recipe that I
suggested for 'Burnt Sand Mastic' which is the Lime and linseed oil and
sand. So, if you get a chance to go there tomorrow or Tuesday to just drop
by, (since we will be done on Tuesday), the guys can show you how effective
the use of this "home-made caulk" is when placing it between wood window
frames and stonework or those areas of differing materials known to be
susceptible to regular lime/sand mortar cracking due to their respective
differential in movement. It is not that the lime doesn't move, it is just
that seasonal expansion and contraction is great with the wood and this
material accommodates this. I know the question was asked on another post
and I will put something there.

-----Original Message-----
From: strawbale-bounces at listserv.repp.org
[mailto:strawbale-bounces at listserv.repp.org]On Behalf Of Sigi Koko
Sent: Friday, May 04, 2007 1:06 PM
To: strawbale at listserv.repp.org
Subject: [Strawbale] Cement vs. clay (was "trashcrete")


HW wrote: <<There seems to be a resistance to cement by some people obsessed
with embodied energy, but personally I find it a more desirable material to
work with than clay slip.>>

The issue with cement is not just embodied energy, but also that a pound of
CO2 goes into the atmosphere per pound of cement produced.  So by my
thinking, if clay is local, has almost zero embodied energy, and produces no
greenhouse gas...it's a winner from an eco-viewpoint.

Thanks, Sigi




Sigi Koko
be the change you wish to see...

DOWN to EARTH
natural building design
environmental consulting
www.buildnaturally.com
215-540-2694 (PA)
202-302-3055 (DC)


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