I’m going to be building a timber frame porch with exposed rafters and roof deck.

I would appreciate feedback on insulating the roof.

I plan to have a roof cross-section that looks something like this:

1×12 pine decking
Solitex Mento Plus WRB
Six inches of salvaged rigid foam insulation in 3 or 4 layers with the seams staggered and taped
1/2″ Advantech or plywood
Ice and Water Shield for the first two feet, then 30 lb. felt
Standing seam metal roof

Do you see any problems with this installation?

Thanks,

BC