It a big experiment that may or may not work.May last a winter or 3??? its a big unknown.
(how much degradation is acceptable, and how often you want to replace any given modular piece, some porosity might work. )Was a great statement.
but until you leave it out there you will not know
What I think is the issue is how long you expect it to last VS how long until it degrades.
With what I know now about clay- I would want it to last and that means vitrified
anything less is asking for failure sooner than later.
sometimes saying no is best for some opportunities.
Your meduim If I recall is Raku and its not made for outside freeze-thaw cycles.
I've worked in high fire... although Raku has certainly been dominant of late. For this project, I was considering high-fire elements with small (mosaic tile style) Raku accents. None of the Raku stuff would be structural or sizable.
Thanks for the test advice Marcia- I'll do that.
I'm thinking that one option may be to craft an external, modular surface skeleton... and then have internal elements (non-structural) made from a porous, filtering clay body.