I’m adding foam to the exterior of a 1950s bungalow with concrete foundation. The rim joists are set into the concrete on the exterior (i.e concrete “flows” up behind the rim joist). Our contractor spray foamed the rim joists from the inside so now I’m concerned about adding foam over the exterior.

I have 6″ foam on the exterior of the foundation and planned to butt the 6″ foam on the exterior of the wooden main walls against it, with an insect barrier between, however, do I now need to add permeable insulation at the rim joist (like Comfortboard) for moisture management and reduce the chance of rotting?

For some of the exterior foundation insulation the foam is wrapped with Blueskin WP200, for both foundation waterproofing and insect protection. Could I use the same material as a “z” channel between the foam on the exterior wall and foundation, or is a metal trim piece a better option?