> The following post appeared today on the strawbale list. I
> thought it might add to the recent discussion of "why strawbale?"
[subject matter re: sill plates, etc.]<snipped>
I think that MeatHook (aka Norbert) presented the wrong strawbale-related
post to this List. I also think that Marc R. presented a cogent and
succinct analysis of the very contentious issue of Breathing Envelopes (aka
Vapour-Open/ Air-Open Constructions, Dynamic Insulation, Porenluftung etc).
vs. controlled (read: mechanical) ventilation.
In view of the discussions that have been going on here, I think that the
parallel StrawBale (SB) List post that MeatHook *meant* to present to the
GB List is the following:
======================== Forwarded Message ==============================
Date: Mon Mar 10 14:00:46 1997
From: dfugler@cmhc-schl.gc.ca (Don Fugler)
Subject: Mold warning
To: strawbale@crest.org
I had a telephone call today from Canadian mold and fungal specialist, Dr.
David Miller. He has extensive training and experience in both agricultural
and residential mold problems and identification. Trust me, there is no
more definitive advice available on mold and health problems.
He had just received the CMHC guidance on how to measure moisture levels in
straw and phoned me to tell me that one of the most notorious molds,
stachybotrys atra, prefers straw over most anything else. Stachybotrys is
universally recognized as a danger to human health (respiratory and immune
system). It has recently been implicated in infant deaths in Cleveland from
pulmonary bleeding. I told him that I assumed there will not be a
significant mold problem without water (or condensation) present in the
straw. Dr. Miller agreed with this assumption, to some extent, but
re-iterated that it is critical to keep stachybotrys out of indoor air.
One step is to avoid materials like straw that stachybotrys prefers.
I thought that I would pass this opinion on. It reinforces what we have
been stating about the need to keep your straw dry, especially after
construction. It also emphasizes that if you do encounter rotting straw
(eg black goop) that you should take precautions to limit possible exposure
of your lungs and skin to stachybotrys.
For further information, there are references to stachybotrys on the
website for the Centre for Disease Control in Atlanta, and in articles in
the New York Times (Jan. 24) and the Washington Post (Feb 11).
< snip >
========================= end of quoted material =========================
As most people on this GB-List may be aware, Stachybotrys Atra (SA) is not
exclusive to straw.... SA is commonly found in conventional, non-SB
constructions which are experiencing moisture problems.
The above quoted material was posted here, not to slam SB construction (of
which I am a very big fan(atic?) and encourage it's use) ... but to
reinforce what Marc R., John A. and others have already pointed out... that
it's very dangerous to be casual about prescribing leaky buildings (under
the guise of "breathing envelopes") as a "healthy, more natural"
alternative to "living in a tightly sealed plastic bag".
For those who have been snoozing.... the (potential) problem that is being
presented IS NOT Straw Bale construction, ...it's the uncontrolled leakage
and moisture accumulation in envelope materials ...of whose effects we are
well-aquainted.
*
While we're on the subject of the regional appropriateness of baled straw
buildings (we were weren't we ?) it may be worth mentioning that for urban
areas where straw is not in plentiful supply, a CMHC report has shown that
urban waste materials (ie plastics + wooden pallets) may be ground up to
produce "bales" with essentially the same structural and insulative
qualities of their rural cousins, straw bales.
These bales can be produced to a uniformity in dimension and consistency
that would delight even the most anal rententive (AR) architect or
engineer.
Quoted from the CMHC report "Proof of Concept: Development and Testing of
the Biocrete House Construction System":
"... one of the world's biggest disposers of "waste" wood
fibre begging to be put to use is said to be General Motors
... wood crates and pallets carrying incoming parts"
I think that MeatHook also meant to post the above too, because he used to
have (and may still ?) the Biocrete report stored at his website for all to
peruse. If not, the report is free for the asking from CMHC.
I think we can assume that Norbert (who is typically a very conscientious
fellow) is feeling the effects of Spring Fever/approaching Full Moon/
Sombrero Fallout and should be forgiven for these "slips".
-- Rob Tom ---------- * ------------ be417@FreeNet.Carleton.ca Kanata, Ontario, Canada __________________________________________________________________ This greenbuilding dialogue is sponsored by Oikos (www.oikos.com) and Environmental Building News (www.ebuild.com). For instructions send e-mail to greenbuilding-request@crest.org. __________________________________________________________________