Hellooooo FABO! I have a 20x20 metal shed roof that I have purchased some heater wire to affix to the under side as last winter there was a snow.....then rain that put a lot of weight on the structure making it deflect about 16". The pitch is slight so snow tends to hang on pretty good. What would the smart people of FABO use to stick that wire under? Magnets? Foil tape? Or.....should I lay it on top?????? Thank you!!! EDIT: it is open underneath. carport over driveway. no insulation but easy access.