I have a one-year old home in Climate Zone 5A with “flash and batt” insulation in the exterior walls. My framing is 2×6, specifically (from outside to inside): vinyl siding, vapor barrier (Kimberly Clark), 2 inches of closed cell foam, R-11 fiberglass batts. I’m not a builder so it’s possible I missed something on the outside.

I’d like to add exterior continuous insulation in the future to increase the R-value of my exterior walls and reduce the thermal bridging through the studs, but also keep my existing insulation inside. My goal would be to add as much R-Value as possible (e.g. 1.5-2 inches of foam board, Zip-R, etc.). At the same time, I would likely look to upgrade at least some of my double-paned windows to triple pane.

What are my options with the exterior insulation? What do I need to consider to avoid condensation issues etc. from my existing construction? Thanks in advance for your guidance!