Will the foil affect cell phone reception?

Modern-day cell phone won’t be effected by radiant barrier foil. An easy way to test is to use a piece of our foil and cover your cell phone with it. Then, call the cell phone from a different phone. If it rings, then the phone should work find after installing foil insulation in the ceiling of your building.
Since radio waves enter a building in all directions, just having foil on your roof should not interfere with your signal. If you’re planning on adding it to all sides, we recommend you order a sample pack and test it out using the method above.