[GSBN] Maximum Density for straw insulation

John Swearingen jswearingen at skillful-means.com
Tue Oct 4 14:47:05 CDT 2016


I would agree...I've never seen evidence of crushed straw in our
industrial-strength 3-string bales.  Softer bales would allow more
air-exchange and convection, reducing the effectiveness as insulation--but
I think the differences will be small.

John "I might be dense, but I'm still soft" Swearingen

On Tue, Oct 4, 2016 at 4:41 AM Rene Dalmeijer <rene.dalmeijer at hetnet.nl>
wrote:

> Rikki,
>
> I see nobody is reacting to your mail. I have not been doing any testing
> myself but as far as I have been able to determine on the tests I have
> seen, it is almost impossible to compress strawbales sufficiently to
> decrease the effective insulation value. One of the reasons for this is
> that in thicker samples some convection takes place in the cavity with open
> cell insulation like straw bales. This means in many cases increasing the
> density improves the effective insulation value to some extent. As far as I
> am aware how much variation has not been determined conclusively as there
> are too many variables influencing insulation values for hole wall systems.
> What I dare to venture to say this variation is not significant given a
> building grade 115kg/m3 straw bale giving an R Value of 5-6 (metric, 28-34
> imperial) for the finished wall. (but as you know this is debatable)
>
> Snug in some warm bales (R 5-6) in the reclaimed swamp at the mouth of the
> Rhine
> Rene Dalmeijer
>
> On Sep 13, 2016, at 12:10, Rikki Nitzkin wrote:
>
> > Hi everyone,
> >
> > Recently returned from our national gathering, I have a question about
> thermal transmission testing….
> >
> > There was a debate going on at our event about what is the “best”
> density for a bale, referring to insulation (not structural) is.
> >
> > Some people were under the impression that “the denser the better” and
> others that an “overly” dense bale will insulate less, as the fibers of
> straw would be crushed and retain less air - therefore insulating less.
> >
> > Has anyone tested this? Is there data anywhere on what the Maximum or
> Minimum Density would be for best insulation?
> >
> > thanks, Rikki
> >
> >
> > Rikki Nitzkin
> > Strawbale Building and Clay Plaster:
> > education, consulting, and building
> > www.rikkinitzkin.worpress.com
> > https://www.facebook.com/TallerConCo
> >
> > tallerconco at gmail.com
> > (+ 34) 657 335 162
> > (+ 34) 974 032 950
> > <PastedGraphic-3.tiff>
> >
> > Coordinator & Professional Member of:
> >
> > <PastedGraphic-7.tiff>
> >
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