Thank you for the post.
We live where the swamp and sand allow the sulphur from oak leaves breaking down to turn my HW heater into an acid cell battery eating the anode and heating element once per year leaving about a foot of sulphur/fluoride deposited in the inaccessible inside. The chunks...
Metal faced film with at least a 3/8 lnch air gap installed in your roof facing the sun will reflect the rays and stop them from penetrating your garage.