I'm building a garage that will be heated in the winter, Zone 5. I'm buying used insulation, and will have R-40 on the roof. If I'm stacking my layers like so: Metal roof Strapping Insulation Ice & Water Decking Do I need to use a high-temperature Ice & Water shield? Or can I get away with a regular temp product since it is underneath the insulation and it will moderate the temperature? Thanks, John

Regular temperature should be fine.

Thanks! I was reading some articles about bitumen bleed, and was slightly worried I might get dripping tar through my T&G.