Fwiw, Sigi does strawbale construction in a relatively humid climate, the mid-atlantic... Dewpoints in the upper 70's happen quite often during the summer (and low-70's probably 50+% of the time). The key is to have a high-enough stemwall to keep the rain splatter away, along with long roof overhangs (but if you think about it, this principle applies to any house--because wood frame construction can rot too!) She is also a HUGE fan of Lime plaster -- No portland cement, not clay (unless you want to re-plaster it yearly), but LIME. It's breathable yet water resistant so it works fantastic for the outer coating in humid/wet climates. (and also the walls in humid rooms like the bathroom, sometimes the whole interior walls can be done in lime if you like ... but many folks do clay plasters with linseed oil sealer or similar)
Down south cob seems to be the way to roll, and it's not too different from strawbale, just no straw bales.. lots of sand+clay+loose straw instead
They do cob out in western OR, in a temperate rainforest climate with good results ... Same principles apply: Good roof overhangs, high-enough foundation stemwalls. In both cob & strawbale construction the typical way to roll is to build the foundation as a "rubble trench" with a trench offshoot that points downhill so water has a sure place to flow if it ever does soak into your foundation, and then an earthen floor in the middle of that, typically dug out first & then (Sigi's technique) plastic sheeting, foam insulation, followed by the adobe floor. I think typically gravel is laid down underneath the sheeting first but my memory is escaping me as to why (maybe help with drainage, in case water wicks up from the earth underneath). There is no basement, of course.
All of that is a heck of a lot of labor & craftwork though, so it's typically a bunch of folks working on it together
(anyway that's a summary from all I've read; my wife got me a whole set of books on cob & natural building last year for Christmas so we've both digested a bunch of them and collected knowledge .... that we'll probably never use, lol, well never say "never" I guess.)
I did get to see one of Sigi's projects, there is a winery very close to our house who contracted her to architect their tasting room... It's beautiful, with green/living roofs for some of it, metal roofing for the main section w/ solar panels, huge thick walls, a cob bench in one corner with throw-pillows all over. We went out on a date last Saturday (w/ babysitter watching the boogers) and visited it for some wine tasting. Natural timbers (de-barked) for support beams, old reclaimed wood for joists, etc.
