[GSBN] Question about SB insulation at foundation/ceiling

Tue Jan 24 17:20:15 UTC 2012

Im guessing someone else has posted this before, but if you want benign you
might look into foamglas- cellular glass that is structural as well as
insulating - the problem may be cost- and availability.
http://www.foamglas.com/

On Tue, Jan 24, 2012 at 10:09 AM, Derek Roff <derek at unm.edu> wrote:

> It would be nice to be able to choose from a richer range of choices than
> the functional, but high embodied energy, toxic, petroleum foam vs. a more
> benign product that may rot.  Making a "lesser of two evils" choice
> guarantees choosing something evil.  It would be great to have ten choices
> with generally positive attributes, but we do have at least one additional
> option.  As I understand it, Roxul Drainboard rigid mineral fiber
> insulation is more environmentally benign than petroleum foam, and more
> resistant to destruction from human, insect, and rodent activities.  One of
> the comments in the links that Joyce gave indicates that Roxul Drainboard
> was selling at a lower cost per R-value, as well, at that time in early
> 2011, in Virginia, if I remember correctly.  I've never used it.  Any
> comments from someone who has?  Any other alternatives that you favor?
>
> Derelict
>
> Derek Roff
> derek at unm.edu
>
> On Jan 24, 2012, at 9:32 AM, Bruce King wrote:
>
> The idea of using any cellulosic material at or near grade just makes me
> nervous and ill.  We have a world of experience telling us that wood,
> paper-faced gypsum board and straw don't last long there, or anywhere near
> there.  Recall Kim Thompson's well-documented problems using bales between
> floor joists over a Nova Scotia crawlspace.
>
> But how, then, to insulate?  I guess I would argue for the use of a
> naturally-occuring substance that can make a durable and also effective
> insulator in the presence of moisture, namely petroleum.  It takes a bit of
> unpleasant processing to turn oil into foam (that is, something that
> entraps air which is the real insulator), and god knows we need to improve
> on the weird stuff currently on the market.  But if there is any good use
> for petroleum, this is surely one.  Not for our cars, not for crappy
> plastic packaging & throwaway junk, but for effective, durable, reuseable
> insulation.
>
> Or anyway I'm still waiting for a viable "natural" ground insulation
> suggestion that isn't a super labor intensive fuss job.
>
> Shredded plastic bags, anyone?
>
> Thanks,
>
> Bruce "Oil gladly pay you Tuesday for some polyisocyanurate today!" King
>
>
>
> On Jan 24, 2012, at 8:08 AM, Frank Tettemer wrote:
>
> 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 <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
>
>
>
>
>
>
>
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