Share 'Polyiso, roxul & reflective insulation combination'

I am working on solutions for a cathedral type ceiling rehab project in a century home in Northern Ohio. The challenge is that there is limited space for insulation and limited ceiling height. There is no viable ventilation in the application (timber frame construction). I am considering a layered application (see attached illustration) -- from the exterior sheathing down of 2" polyiso foam (r11)…