Insulate roof and attic?

[Coder]

Contractor wants to insulate both the underside of the roof sheating and the attic ceiling to obtain the required R-49. Basically half and half. I don't see how this will work. Any ideas out there?

 

[steveray]

Attic is ventillated......correct?......NG.....

 

[Coder]

With the current configuration the attic should be vented. Not sure what it looks like yet. The only option for the contractor I see is creating an un-vented attic with the full R-value in spray foam on the underside of the roof sheating and making that the building envelope. Then the attic would become part of the conditioned space. The attic ceiling insulation wouldn't be usefull at that point IMO.

 

[steveray]

With the current configuration the attic should be vented. Not sure what it looks like yet. The only option for the contractor I see is creating an un-vented attic with the full R-value in spray foam on the underside of the roof sheating and making that the building envelope. Then the attic would become part of the conditioned space. The attic ceiling insulation wouldn't be usefull at that point IMO.

Correct...IMO....Why are they limited in the ceiling? Usually run into problems at the eaves, put you can keep piling that stuff on in the attic.....

 

[Coder]

I agree Steveray. Still waiting for the contractor to call me back for further analysis of the current situation. Thanks for the replys though. It is helpful to bounce ideas off of someone. I agree that they just need to add more to the lid and forget about the underside of the roof sheating.