Attic ventilation and insulation

[Carey]

Daniel, we used the Reflectix radiant barrier in the attic (it is fire rated....I used to inspect for UL, so I am a little over the top on checking that roofing materials are fire-rated...), it is still very reasonably priced, but not as cheap as snagging used balloons and coffee bags (but that is a very environmental stewardship thing to do with mylar waste...)
Some mylars do de-laminate, esp with the thermal swings & UV in the attic