Drainage plane at cantilever w/ ComfortBoard - GreenBuildingAdvisor

Drainage plane at cantilever w/ ComfortBoard permeable_ | Posted in General Questions on April 8, 2026 12:47pm Renovating a 1970’s home, climate zone 5A, over 2000′ in elevation on a hillside so there’s extreme weather. All but one wall of the second floor is cantilevered out over the first floor. In some places 8″, in others 30″, and at the main entry over 8′. As part of the renovation I’m looking to upgrade the insulation. I’m committed to the assembly being as vapor-open as possible, so I’d prefer mineral wool batts in the existing 2×6 stud walls, complimented by 2″ of mineral wool boards outside of the sheathing. I prefer the WRB to be at the sheathing for various reasons, mostly to do with the windows. This leads to an aesthetic conundrum at these overhangs. Since you’ll be walking under them to get to the front door of the house, seeing the underside of the mineral wool and cor-a-vent is unacceptable. Is the only solution to use a soffit vent to allow any bulk water that gets past the siding to drain out? Or am I overthinking this (it’s shiplap so in theory there shouldn’t be much water intrusion) and I would be fine to just continue my soffit boards across this area? Maybe instead of gapped  shiplap at the soffit I use square boards with a 1/4″ gap for increased airflow? I’ve read this article https://www.greenbuildingadvisor.com/article/positioning-control-layers-in-a-cantilevered-floor but since it uses zip-r it’s not really applicable to my situation. I drew up a...