[GSBN] steel clad barn and straw bales

[martin hammer]

Rob Tom mentioned girts, and presumably these horizontal framing elements
exist (to which the steel cladding is fastened).  By virtue of the girts
there would be an airspace and no contact between the bales and the steel
cladding, although the thermal bridge of the girts (especially if metal)
could create local conditions that promote condensation.

Assuming the bales would be tight against the girts, the girts would serve
as fire stops to a large extent (though any corrugations in the cladding
could still allow vertical passage of air), but I agree with others that an
earthen plaster (or at least a clay slip) should be applied to protect the
outer surface of the bales from fire, as well as help manage any moisture
that might condense on or otherwise reach that area.  Rodent or insect
intrusion would be another reason to apply plaster (more effective for this
purpose than a slip) to the exterior bale surfaces.  Finding a way to do
this without removing and reinstalling the steel cladding is worth pursuing,
either by dipping each bale in clay slip (might be sufficient) as John
Straube suggests, or using a pre-fab tilt-up panel as Chris Magwood has
done.

Martin (true girt) Hammer


On 10/8/11 5:01 AM, "Chris Magwood" <chris at chrismagwood.ca> wrote:

> One way to build such a wall with plaster on the metal side would be to
> build it as a tip-up panel. You can make a form box on the floor in
> front of the wall and build it like we do our prefab panels. The
> finished panel could be tipped up directly into place. You can get a PDF
> on our method for doing this at
> http://endeavourcentre.com/materials-technology/. I'd be glad to help
> you out with any questions about doing this in place.
> 
> Chris
> 
> On 11-10-07 8:37 PM, John Straube wrote:
>> I am with Tom: the ideal construction is to provide an earth plastered SB
>> with a 1" airspace and then the metal cladding.  The rain control would also
>> be excellent.
>> In your case, building from the inside with a pre-existing metal clad barn, I
>> am not sure how to do this.
>> 
>> Condensation is very likely in a UK climate if there is even a little
>> interior humidity and the bales are placed tight against the cladding.  In
>> storage barns (no interior moisture generation), bales are often placed close
>> to metal cladding, usually there is a 2 to 10 cm space, but sometimes they
>> touch.  I have only seen rot in these situations when interior humidity
>> (livestock) where added to the inside.
>> 
>> As a minimum I would leave an air space.  however, if at all possible,
>> dipping bales in a clay slip before laying up with a 3 or 5 cm air space and
>> interior plaster may be the best you  can achieve. I would be careful to
>> provide screens at the bottom to resist the entry of animals.
>> 
>>