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

[John Swearingen]

I agree with Graeme that some moisture accumulation will occur where
migrating vapor strikes an impermeable surface.  Lay a piece of wood on top
of a bale stack, and within a short while there will be discoloration the
footprint of the wood.  For me, this is the reason to use gravel base in
favor of rigid insulation at the bottom of a bale wall.  Whether this factor
is significant or not in the life of a building, is another question.  I
think not.

I agree with Jeff that the main issue with steel and plaster cracking is
when the length of a steel member expands and contracts.  Working around
steel x-braces before plaster, we've watched them grow slack in the
afternoon sun; and we've seen 1/4" x 3" steel x-braces clearly outlined by
cracks in the plaster on the warm side of a building, and not on the shaded
sides.

We built a tall octagonal barn using a 6x6 tube steel frame, and cracks
appeared at the corners on the sunny side, only.   Another building had very
large, two-story X-braces integrated into a wood frame.  Some cracking
occurred where the two systems came together.

John "Sunny Side Up" Swearingen



On Wed, Jun 17, 2009 at 8:47 AM, 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
>
>
>
>
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-- 
John Swearingen

Skillful Means
www.skillful-means.com
blog: https://skillfulmeansdesign.wordpress.com
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