[Cob] what are concerns

[philmoulton at comcast.net]

Am consideering tearing off most of the house, pouring a foundation and adding on a cob livingroom and bathroom about 22x26 ft onto the existing kitchen which is on pier blocks.
The existing kitchen roof would be torn off and extended to the cob addition as part of its roof.
I am on the west side of the cascades about 7 miles from the Pacific ocean.
Does anyone have experiance building in the Oregon cascades and what kind of attachment/seperation issues should I be aware of.

Phil