[strawbale] [RENOVATION:] wing insulation made of straw

[Herbert Gruber <d.sign@aon...>]

Dear strawbalers
I found an interesting article about a straw(bale)-insulated foundation. I
read about frost shallow foundations, as used in scandinavian countries,
using horizontal EPS-insulation, but I never heard about wing-insulation
made of straw. This would be a possibility to insulate and dry old houses,
too... Here is the story. If you are interested in the details (graphic
picture), please download it here:
http://www.baubiologie.at/wing_isolation.html

Wing Isolation
The Underground Space Center at the University of Minnesota did some
excellent research in the late 70's and early 80's pointing to the fact that
horizontal "wing" insulation was preferable to vertical foundation wall
insulation. Wing insulation was shown to keep the earth near foundation
walls dry, greatly increasing the insulation's efficiency. Expanding greatly
upon this concept, John Hait published Passive Annual Heat Storage (PAHS) in
1983. This work was dedicated to a very basic concept that is ignored by
nearly all architects: keep the ground under and around the home dry and you
can use it for an amazingly effective heat sink and seasonal temperature
moderator.  After all these years, I am still shocked and amazed at the
ignorance shown by designers who insist on leaving the foundation walls in
contact with wet earth.
One of the most important design factors for sustainable, high thermal mass
(HTM) construction is wing insulation around the perimeter of the foundation
wall. As the sketch below outlines, we stress the need for waterproofing and
insulating up to a 20 foot* perimeter around the home (*less than 4 feet is
a waste, 8 feet is better, 12 feet is an economic compromise, 16 feet is
typical, 20 feet is best in extreme climates). Wet earth near your
foundation acts as a constant drain pulling energy away from your home. 
This is a mistake you simply cannot afford, literally.

Best wishes from Austria
Herbert Gruber, ASBN

PS: The Report for the ESBN-Gathering will be ready end of this week...