Slate Sheathing Exterior Wall – “Direct Apply” – GreenBuildingAdvisor

Cupaclad makes a slate product designed as a ‘rainscreen’ with slate tiles screwed to frame attached to wall with exterior insulation.  Very nice but also more intense labor, etc.

They also show a ‘direct apply’ application in which they screw directly to the sheathing and use HDPE waterproofing between courses essentially covering all the sheathing with HDPE.

We are using 2×6 framing with plywood sheathing and mineral bats inside.

I’m assuming some WRB/Tevdek would go over sheathing and this would go over that directly.

My question is…….are there concerns regarding the sheathing and rot??

I’m thinking this won’t let the sheathing breath enough with the HDPE.

What does everyone think?