I have am considering putting up 1" foam on the interior side of rafters on a cathedral ceiling, very bad ice daming going on and very difficult access to attic. Ceiling has R30 and blown 10". The attic has been airsealed and I think the T&G is a leaking mess and currently nailed to the rafters with no backing of any kind. Any thoughts would be great. If you need more detail please ask thanks in advance for your input guys.