Bale moisture during plastering

["Bill Hunt" <billhunt@redrock.net>]

Hey now, straw world!
Has anyone monitored  bale moisture during plastering?  I'd like to see
some other data on this. 
I've been monitoring the current sb project with a Protimeter probe-type
meter. We have plastered the exterior with a thin coat of clay slip, 2-3
coats of lime plaster, a texture coat of similar mix (but no fiber) and 2
coats of limewash.  It is mid-winter in Utah, and the site is at 7200'. The
structure is fully tented, and heated above freezing most of the time (for
areas of fresh plaster).   

Two factors that increase moisture levels are: 
1. Drying is slowed by the cold temperatures.  (Microbial activity is
slowed as well.)
2. Curing lime plaster properly involves keeping it moist.  Misting is also
necessary before each coat of lime (but not needed before the clay slip). 

Here are some moisture content averages at progressive distances into the
bale walls.  All aspects and elevations are averaged here (they are
generally similar, though some interesting patterns are developing).
Distances are measured from the inside bale surface. 
 The Protimeter is a hay meter. I think these are "wet measure" numbers . 
Distance	Avg. Moisture Content 	# of sites averaged	
18.5 to 19"	32%			22 (the probe is touching the exterior plaster)
18"		27%			12
16"		17%			13
14"		13.5%			13
12"		11.7%			14
10" 		9.8			7
8"		8.6			7

Here is a cross section of moisture content through an area that was
plastered on the exterior as above (over many weeks, since before the
holidays), then plastered on the interior with one coat of lime plaster
(only one small area has been done on the interior).  
"Distance" is from the interior plaster surface. 
Distance 	Moisture Content
2"		20%
4"		16.9%
6"		12%
8"		10.2%
10"		8.9%
12"		10.7%
14"		14.3%
16"		19%
18"		25.4%
19"		31.8%


We draped plastic over most of the first and half of the second coats. 
This reduces cracking quite a bit, and helps cure the lime better.  This
may drive the moisture into the bales a bit more, but I think it also may
help cure the lime well with the least amount of water put on the wall. (I
don't think further misting is needed if the plaster is fully draped with
plastic. Salvaged plastic, old tarps, lumber wrappers, etc could be used)
As Mr. Steen noted, " This may be a good argument for a layer of the clay
plaster in-between the bales and the lime." This would be feasible in
temperatures over 50 deg. F.




Everyone I've spoken with so far feels the straw will dry out OK. Our
current schedule
calls for us to plaster the interior of the building soon.  

Another incident that has occurred is that there was a leak in the
antifreeze (glycerine) sprinkler system, in a box beam over a bale wall.  I
think the outer inch or two of the interior and exterior of the top few
bales got "wet".  The exterior is plastered. Does anyone know if straw with
glycerine on it will support microbial growth?  It sounds like glycerine
won't break down or "dry" in the near future. 

Thanks for any input. 

Cheers- WasatchBill

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