[GSBN] Question about SB insulation at foundation/ceiling

[Frank Tettemer]

Hi all,

I have just received a message from the designer of the yoga centre, 
that I was busy criticizing in my previous post.
The Sivananda Yoga Centre is still alive and well over a decade later.

I apologize to the GSBN group, and to Michel Bergeron, for handing down 
that mis-information about the Sivananda Yoga Centre. Michel has had no 
such reports of mold problems, and as the designer, he would certainly 
be the first to hear about it.  It takes a foolish commnet from someone 
like me, to deeply upset the credibility of straw bale construction. And 
worst of all, this negative comment coming from a straw bale builder!

There's a strong lesson in all this for me, to examine all my sources of 
information, and to not speak about things of which I have no first hand 
knowledge.

Deeply chagrined, deeply humbled,

Frank Tettemer


On Jan 24, 2012, Derek Roff wrote:
I'm not sure if this discussion is still alive on the linked site that 
Joyce posted.  The newest posting is just about a year old, but perhaps 
the discussion will warm up again.  Bruce King posted a comment last 
year, when the discussion was current.

Something that wasn't mentioned in the article or comments is the naive 
assumptions regarding the effective insulation value of the strawbale 
waffle slab design, even before the bales start to rot.  The assertion 
is made, and not challenged, that the under-slab strawbale insulation 
would provide R-50.  Whatever number we accept as the insulative value 
of each bale, the thermal bridging of the concrete in the matrix would 
cut the effective insulation of the waffle slab design dramatically. 
  Thermal bridging isn't a problem with the design sketch that Joyce 
included, but the risk of rot probably remains.

There is an alternative approach that uses bales as floor insulation, 
but above grade.  After a European Straw Building gathering a few years 
ago, traveling with Catherine Wanek, I visited SB buildings in half a 
dozen countries, including several that used strawbales in the floors, 
to meet Passiv Haus design goals.  All of these structures were build on 
piers, so that the bales were above grade and isolated from the moisture 
concerns that afflict buried bales.  Here is a link to one example, the 
S-Haus in Austria.

http://www.s-house.at/presentations.htm

Bale-on,
Derelict

Derek Roff
derek at unm.edu <mailto:derek at unm.edu>

On Jan 23, 2012, at 10:40 AM, Frank Tettemer wrote:

Well now,
that is pretty interesting.
Thanks, Joyce, for sounding the alarm.

Before I actually (physically and personally), had built any SB houses, 
I naturally ass-u-me-d that bales in the floor and ceiling were a good idea.
It is too bad that the article in finehomebuilding references the 
experimental work of Michel Bergeron, of ArchiBio, in the 
ground-breaking book of Steen/Steen/Bainbridge/and Eisenberg.  I love 
the book, and it is what gave me hope for the idea of burying bales 
below grade.

Fortunately for me, Linda Chapman, (archi. from Ottawa), talked with me 
about doing this in the early nineties.
She had boldly gone where no one had gone before. And the floor rotted.

And there was the evidence from the huge three-story yoga retreat 
centre, built in Quebec,
which was such a rotten embarrassment, that I won't mention it anymore.

Then there's the theory that if you stick each bale into a garbage bad 
before you bury them under the floor ...
just to say I did, I took a bale, put it into a garbage bag, and placed 
it into a weather-protected shed, to see what happened.
First of all, it took three trys with the garbage bad to place a bale 
into it, without it being punctured by straw.
Secondly, during the summer of 2000, which was a fairly wet year, the 
bale self-composted, with out having had a drop of rain on it. I imagine 
that relative humidity was all it took. It was full of mildew in two 
months time.

I have to say, though, that the idea is so intriguing, that it captures 
the imagination of quite a few clients, who would wish me to design a 
foundation using straw bales.
Maybe it's just a stupid idea, here in a climate with huge weather 
extremes, (+35C to -35C), and many days of damp rainy weather?
Maybe all the ideas have not been tried as yet?

Frank