I am in the process of building large spec homes in Montana and was wondering if there were benefits to using these tiles to enhance a cold roof design?
Properly installed tile roofs actually create a sort of cold roof by the way they are installed. The space created between the tile and the roof deck allows for ambient air to cool any heat loss that may escape the roof system. This is one of the reasons that tile roofs are the preferred roofing material in alpine regions around the world. The method of installation in severe winter climates however is very important and I would suggest that you reference the NTRMA / WSRCA Design Criteria Manual for Cold and Snow Regions for more specific information regarding your roof.