alohart
Well-known member
The clear coat top layer of an i3's CFRP roof degrades when exposed to solar ultraviolet (UV) radiation. Solar infrared (IR) radiation heats the black CFRP roof reradiating IR radiation down into the passenger cabin where it is detected as heat. These problems are most serious in climates with intense sunshine. Reflecting solar UV and IR radiation from the roof would decelerate the degradation of the CFRP clear coat and would reduce the cabin's temperature. Changing the color of the roof to a light color would solve both problems.
I just had the roof of our 2019 i3 wrapped with silver metallic vinyl film, a close match to the Frozen Gray highlights of our Imperial Blue Metallic i3 and the decal along the sides of the roof. Local shops won't order vinyl film for such a small job, so my color selection was limited to what shops had on hand. I found a shop that had just enough silver metallic film left over from a larger job to wrap the roof.
There's no warranty on wrapped horizontal surfaces due to the same UV radiation that degrades the CFRP clear coat. If our car were exposed to our strong tropical sunlight much of the time, I was told to expect this film's appearance to become chalky within a year or two with it degrading so much that it would be difficult to remove because it would fall apart. So wrapping probably isn't a good solution for i3's that spend a lot of time in sunshine unless one is willing to replace the vinyl film every couple of years. A light-colored paint would probably be a better CFRP clear coat protectant.
The roof of our 2014 i3 which we bought new looked good after almost 8 years. I don't know how much southern California solar exposure our used 2019 i3 experienced, so I wanted to do something to protect its roof. It won't spend enough time in direct sunlight to degrade the vinyl film rapidly, so vinyl film should be a good solution for us.
Of more importance to me is the reduction of IR radiation into the cabin which is quite noticeable from the underside of the roof. Replacing the black CFRP surface with a light gray surface should reflect some of the solar IR radiation and make the cabin slightly cooler.
Members of the Facebook BMW i3 Worldwide Group can see a photo of the wrapped roof.
I just had the roof of our 2019 i3 wrapped with silver metallic vinyl film, a close match to the Frozen Gray highlights of our Imperial Blue Metallic i3 and the decal along the sides of the roof. Local shops won't order vinyl film for such a small job, so my color selection was limited to what shops had on hand. I found a shop that had just enough silver metallic film left over from a larger job to wrap the roof.
There's no warranty on wrapped horizontal surfaces due to the same UV radiation that degrades the CFRP clear coat. If our car were exposed to our strong tropical sunlight much of the time, I was told to expect this film's appearance to become chalky within a year or two with it degrading so much that it would be difficult to remove because it would fall apart. So wrapping probably isn't a good solution for i3's that spend a lot of time in sunshine unless one is willing to replace the vinyl film every couple of years. A light-colored paint would probably be a better CFRP clear coat protectant.
The roof of our 2014 i3 which we bought new looked good after almost 8 years. I don't know how much southern California solar exposure our used 2019 i3 experienced, so I wanted to do something to protect its roof. It won't spend enough time in direct sunlight to degrade the vinyl film rapidly, so vinyl film should be a good solution for us.
Of more importance to me is the reduction of IR radiation into the cabin which is quite noticeable from the underside of the roof. Replacing the black CFRP surface with a light gray surface should reflect some of the solar IR radiation and make the cabin slightly cooler.
Members of the Facebook BMW i3 Worldwide Group can see a photo of the wrapped roof.
