[Cob] Lime wash over AE?

[Quinn]

My question is about AE in general.  While I understand that AE is water resistant (waterproof?), I am befuddled by peoples enthusiam over it, seeing as its a petroleum product, its noxious, we are running out of oil, etc.

My interest in alternative building is not only to build myself a nice warm, dry structure in which to live [if that were the only goal there are certainly unlimited non-renewable, durable, waterproof plastic materials in use everywhere we look], but to create something with minimum impact on the planet, something healthy in which to live (no off-gassing) and to set an example to others that these values are do-able.

AE seems counter to that goal.  Any thoughts on the matter?

Quinn