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

[Clarke Olsen]

If a vertical piece contacts a horizontal, it's hard to see that wicking won't occur. Best would be an angled bottom cut with a minimum 1/8" space and caulk set back from the face.

Clarke Olsen
clarkeolsendesign.com
373 route 203
Spencertown, NY 12165 
USA
518-392-4640
colsen at taconic.net




On Feb 20, 2014, at 5:27 AM, Alan Abrams <alan at abramsdesignbuild.com> wrote:

> 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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