Thread: Extending R-value for cathedral ceiling
View Single Post
  #4   Report Post  
Posted to alt.home.repair
Chris Friesen Chris Friesen is offline
external usenet poster
  
Posts: 1,185
Default Extending R-value for cathedral ceiling
wrote:
Chris wrote:

The roof rafters are 2" x 8". For that size, I should use R20
(6") in order to keep 2" for ventilation on the top of insulation.

Why not put up a good plastic film vapor barrier under 8" of insulation?

You're supposed to leave space for airflow between the insulation and
the underside of the roof.

Chris
Reply With QuoteReply With Quote