[GSBN] Use of and protection - steel columns in bale walls

[Derek Roff]

Jeff raises some important questions, ones that I wish I had had in 
mind when I was inspecting the moldy straw against the steel in the 
instances that I referred to.  I'm now trying to think back to what I 
can remember of the incidents, and I can't be certain of the details. 
In no cases was the straw around the steel palpably wet.  In one case, 
I remember thinking that rising damp was a problem, because of 
noticeable (though superficial) rust for several inches up from where 
the steel met the stem wall, and the lack of a moisture barrier there. 
In the other cases, I'm just not sure how much moisture might have been 
involved.  One of the cases was a major remodel, and the other two were 
small workshop buildings that had stood for a few years, and were no 
longer needed/desired.

I agree with RT's comments, with the caveat that there are several 
other ways to introduce moisture into a wall, besides a bad air 
barrier.

Derelict

--On Wednesday, June 17, 2009 8:47 AM -0700 Jeff Ruppert 
<jeff at odiseanet.com> wrote:

> In terms of a moisture and condensation issue, I have to agree with
> Paul Olivier about his comment on climate.  I would be more concerned
> with it in a wetter climate than a dry one.  Texas can get pretty
> humid though.
> My question to Derek is, were the walls you dismantled being torn
> apart due to moisture issues?  The reason I am asking is that all the
> walls I have dug into have been due to moisture intrusion.  I have
> seen rebar imbalers rusted out within a couple years because they
> were soaking inside a wet bale.  How many buildings do we tear apart
> for other reasons than moisture?  What would a non-wetted wall with
> steel columns look like?
>
> My next thoughts are about how a similar material to straw acts when
> in contact with steel.  The closest material would logically have to
> be wood.  I have not heard of widespread rot issues from wood being
> in contact with steel.  Does anyone have different observations about
> this?
>
> My experience with steel posts in walls has led me to believe that
> the expansion of the steel across it's cross-section is much less of
> an issue than along it's length.  As the frame heats up columns and
> beams grow in length quite a bit compared to their depth or width,
> placing stress on the plaster (if the plaster is attached to the
> frame).  If I were to do other steel buildings I would not attach the
> plaster to any steel elements.  We used wood nailers fastened (with
> power-actuated fasteners) to the steel columns.  Our mesh was
> attached to those nailers.  As the frame expands and shrinks
> throughout the year, it appears to place alot of stress on the
> exterior plaster.  The frame is set to the exterior.  I believe if
> the frame was on the interior this action would be eliminated.  The
> steel members were wide-flange moment-frame sized, not light framing
> like studs.
> We did not design the building described above and the frame and
> foundation already existed when were began our work.  In retrospect I
> would have suggested not using bales due to the fact that we could
> not alter the configuration to accommodate a better system.
>
> Jeff



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 at unm.edu