I have a timberframe under construction with a 14/12 roof pitch, and 8" Structural Insulated Panels. I am planning on installing a cold roof over the panels with 2 X 2's on 16" centers and covered with 1/2" OSB. My roofer has questioned the attachment of the 2 X 2's to OSB on a steep pitch, with nothing "substantial" to anchor to. Are there any thoughts on the proper method of attachment in this application?