[Greenbuilding] protecting outdoor wooden structure from future decay (or at least delaying it)

[Alan Abrams]

it's worth considering the dynamics of failure.  just had a call to look at
a structure my co. built in 2005--some of the vertical 1x's that trim the
corners are starting to get punky where they sit on the horizontal drip
cap.  It's fair to surmise the carpenters did not spot prime the cut ends.
 Regardless, it raises the question whether the corner boards are wicking
moisture up from the water landing on the drip cap, or osmosing moisture
from some other souce down its length, where it accumulates at the bottom.
 Or both...

another recently manifested failure (due to a tiny but insidious leak in
the overhang of a green roof) led to some reading about the repair of
wooden boats.  It appears that propylene glycol--marine anti-freeze, in its
simplest form--has a double value.  First, it is hygroscopic, and if
applied to damp wood will bond with and draw out, and evaporate away that
moisture. (Acetone will also dry out wood very quickly)  Second, and more
to the point, wood that has absorbed P. glycol (which is relatively non
toxic--it's rated GRAS and used in all sorts of food and cosmetics) tends
to resist rot.

going back to the issue of the vertical trim board rotting from the bottom
up, it might make sense to immerse cut ends of vertical members in a pan of
P glycol for a few moments before installing them. because it would not
seal the wood, it would not matter whether moisture was drawn up or down.

AA
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