Window detail: innie window with Rockwool, rainscreen, and stucco
I am almost ready to install windows (Marvin Integrity Wood Ultrex w nailing fins) on my remodel in CZ 3c. I’m still struggling with the window detail. Wall plan is 2×4, plywood sheathing, Blueskin, 1.5″ Rockwool, 1×4 vertical furring strips to create a rain screen, Cor-A-Vent horizontally on the top and bottom, and stucco cladding (on paper backed lathe).
Our original high-level plan was to have stucco returns on the head and jambs, and figure out something wood on the sill. I’m stuck on how to detail the head and sill so that the rainscreen cavity is still ventilated, and not draining any water back towards the window.
One idea was to add a z-flashing on the head, and the best detail I have found for that is in Chapter 5 of the The Guide for Designing Energy-Efficient Building Enclosures for Wood-Frame Multi-Unit Residential Buildings in Marine to Cold Climate Zones in North America, excerpt attached (and full guide available at this link: https://rdh.com/wp-content/uploads/2014/07/Guide-for-Designing-Energy-Efficient-Building-Enclosures.pdf).
If we go with a detail like that, then I have wood at the head, metal at the sill, and stucco on the jambs. I’m worried about the consistency of multiple trim finishes; and another option would be to trim the jambs with wood as well.
Our preference is stucco on three sides of the window. Is it possible to have a rain screen under stucco and still have stucco returns on the head (and/or sill)? Alternate ways to detail innie windows with stucco over rainscreens? Any ideas appreciated, thanks!
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