Insulating exterior of 70’s-built T&G cathedral ceiling, Zone 4a — Q1: Vented or Unvented?

Long-time reader, first-time writer. Thanks in advance for your time, expertise, and consideration.INSULATION DESIGN AND APPLICATION QUESTIONIn Zone 4a, which insulation method is preferred for T&G cathedral ceiling?4″ vented polyiso… Long-time reader, first-time writer. Thanks in advance for your time, expertise, and consideration.INSULATION DESIGN AND APPLICATION QUESTIONIn Zone 4a, which insulation method is preferred for T&G cathedral ceiling?4″ vented polyiso…Read MoreGreenBuildingAdvisor