Chances are that you currently use your cell phone in metal roofed buildings regularly. If you currently have very, very weak or spotty cell phone reception inside of your home, a metal roof may be the “straw that breaks the camel’s back.” Adding a cell phone signal booster in your house would have been helpful before the metal roof and certainly would be helpful after your metal roof is installed. However, if you have fair to excellent cell phone reception now, the metal roof should not have any noticeable effect.