I'm having a log home built wth cathedral ceilings. I plan to have 1 1/2 to 2 inch closed cell polyurethane sprayed onto the interior side of the roof sheathing with blown in insulation filling the balance of the twelve inch rafter (I beam style of rafter) cavity. This wll be an unventilated roof. Tongue and groove will be used on the ceiling surface. I understand the spray foam will act as an air barrier, and the tongue and groove is very air permeable. Other than localized heat from the IC recessed light, is there any other reason to avoid these with regard to this roof design, or should they just not be used in this situation? Thanks.