[Strawbale] Window/sill details

[Dion Hollenbeck]

I just received my copy of Bruce King's "Design of Strawbale 
Buildings" and while skimming through it before setting out to 
actually read it, I noticed something peculiar with all of the window 
design pictures and drawings.  Almost without exception, the windows 
are recessed into the bales, presenting the necessity of a window 
sill.  Duly noted in the book is the care with which this design 
requires so that water from above and also that falling on the sill 
is carried away from the window itself.

When I built my workshop, I took a very different approach.  All of 
the windows are completely flush with the outside of the walls.  In 
my thinking, this would prevent any such water situations from 
occurring.  The windows were nailed into wooden bucks, with bitumen 
flashing all around (applied bottom to top like shingles), and then 
expanded metal on on top of that to prevent cracking in the window to 
bale transition.  Then, finally, on top of it all, the whole window 
was surrounded with folded metal that is designed to create a small 
gap between the window frame and the stucco.  After all coats of 
stucco had cured, this gap was then filled with silicone caulk, 
preventing cracking/separating at the junction of stucco and window frame.

With all the possibilities for water to get into improperly detailed 
windows installed with the "sill approach", I wonder why anyone would 
choose the "aesthetic" approach over what appears to me to be a much 
more robust water shedding approach of windows in the plane of the 
outside of the wall.

Am I missing some key concept, or is my engineering mind just more 
concerned with robustness than it is with "pretty"?

regards,
dion

--
Dion Hollenbeck
Email: hollen at woodsprite.com    Home Page: http://www.woodsprite.com
Brewing Page: http://hbd.org/hollen   Toys: 98 4Runner, 86 4x4 PU