[Cob] Moisture Barrier Mobile Home

[Amanda Peck]

I hear from some more-or-less natural builders that Tyvek in particular has 
benefited from an inflated reputation.  Typar may be a bit more breatheable, 
but--see below.  They seem to be using the felt as easier to handle (nine 
foot wide rolls sound a right unpleasant to stretch evenly across anything) 
and maybe better--at least more of a history.

Here is one of a series of articles from the University of Massachusetts on 
a handful of building subjects.  He does like the 15 pound felt.  Some 
people seem to like it because it does wrinkle.

http://www.umass.edu/bmatwt/publications/articles/leaky_housewraps.html

"I ... remain convinced the leading cause of water damage is poor design. 
Proper flashing and the integration of flashing with an able housewrap are 
perhaps the most critical details enabling walls to function as weather 
barriers.
..........
Non perforated wraps (Tyvek and Rwrap) and 15-pound felt paper won that 
round by a knockout. Perforated wraps leaked like sieves. I also did some 
exploratory work to determine the effect of soaps (from powerwashing) and 
water soluble extractives (like those found in cedar and redwood) on water 
permeability of housewraps and determined that soaps and to a lesser degree 
extractives can cause wraps to leak. As promised in the November 1998 issue 
of JLC, I have extended the study to look at the ability of housewraps to 
block the capillary flow of water."