Re: [Strawbale] Convection in SB walls

[Derek Roff <derek@unm...>]

I don't think that convection through the middle of dense bales is a 
significant problem.  The convection that RT and André are discussing 
is between the bales and a cladding material, hence, outside the plane 
of the bales.  Air movement in the vertical spaces between the ends of 
the bales in each bale course (row, layer) is likely to be much larger 
than within a bale, even with good stuffing, but if the bales are laid 
with a running bond, then the vertical distance will only be the height 
of one bale at each location.

The "French Dip" method of dipping each bale in clay slip, before 
stacking the bale in the wall, is a technique that a number of people 
have tried.  I think it has some pluses, relating to both air movement 
and fire resistance.  Fire resistance is most critical before in the 
construction phase, before the plastering is completed.  French Dip 
gives you a significant increase in safety, during this critical phase. 
But it is rather messy.

Derelict

--On Wednesday, December 8, 2010 9:43 PM +0000 Dave Howorth 
<dave@howorth....uk> wrote:

> On Wed, 2010-12-08 at 21:58 +0100, forum@lamaisonenpaille... wrote:
> > the convection that is common in fibrous insulation materials.
>
> I've wondered what can be done about this. Convection needs height to
> really get going so I wonder if some less permeable layer laid
> horizontally between the layers of bales might reduce it some.
>
> Obviously you don't want it totally impermeable to water vapour or
> liquid, and you want it cheap. So for a completely off the wall idea,
> how does laying sheets of old newspaper on top of each row of bales
> sound? They'll get holed a bit but that shouldn't matter too much.
>
> Cheers, Dave



Derek Roff
Language Learning Center
Ortega Hall 129, MSC03-2100
University of New Mexico
Albuquerque, NM 87131-0001
505/277-7368, fax 505/277-3885
Internet: derek@unm...