Best plaster for temperate rainforest

I'll probably look for alternatives to cob in future building here, but how should I attempt preservation of the cob structure that's already in place in this temperate rainforest?

Ryan, If you are talking about an exterior plaster, I would try a lime-sand plaster applied to the cob...You might want to read the chapter in my book, however, so you can learn as much as possible about lime-sand plasters. They can be tricky and require a lot of knowledge. Good luck.