Wrapping Roof with Vinyl Film

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alohart

Well-known member
Joined
Nov 1, 2014
Messages
3,081
Location
Honolulu, HI
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.

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Looks nice Art! I do worry about my roof deteriorating, as some have e xperienced, but I also like the look of the black roof on my white/black "Panda". But maybe a black wrap would be an option. Wouldn't address IR radiation into the cabin but it would probably be chaper to replace a black wrap every couple of years than to have a bubbled roof repaired. Where I live we have fairly intense sunshine (high 90's and low 100's) for only a few weeks each year, and regular summer sunshine (70's and 80's) for 2-3 months, so it definitely isn't as hard on the roof as where you live. But still....
 
Fisher99 said:
I do worry about my roof deteriorating, as some have e xperienced, but I also like the look of the black roof on my white/black "Panda".
If I had a Capparis White i3, I'd have the roof painted Capparis White to match. Like the clear CFRP top layer, vinyl film will deteriorate in strong sunshine whereas automotive paint won't. Also, a Capparis White roof would reject heat better than just about any other color. While I understand your appreciation of the contrasting colors of a Capparis White i3, the roof isn't especially visible, especially if the rear spoiler remains black.
 
My 2014 had the CF roof and I loved looking at it every time I got in the car.

The 2021 has a sunroof (which I do love) but I miss the CF roof.

While the concept of UV damage to the roof makes some kind of sense, I've been on the forum for a long time and can't recall any posts about such degradation.

As the roof is a structural component and BMW has been in the business for a while, it doesn't make much sense that they could have fouled up so badly here but I'm really interested in any available tales.

p.s. The wrapped roof does look sharp, alohart!
 
frictioncircle said:
My 2014 had the CF roof and I loved looking at it every time I got in the car.
You must be tall! I can barely see the roof unless I stand on my toes.

frictioncircle said:
While the concept of UV damage to the roof makes some kind of sense, I've been on the forum for a long time and can't recall any posts about such degradation.

As the roof is a structural component and BMW has been in the business for a while, it doesn't make much sense that they could have fouled up so badly here but I'm really interested in any available tales.
There have been several Facebook Worldwide BMW i3 group posts about deteriorating roofs and DIY repair attempts as an alternative to the very expensive out of warranty roof replacement by a BMW dealer. I've read reports of BMW M cars with CFRP roofs having similar roof degradation problems. If it occurs under warranty, BMW seems to be replacing them at no cost.

In June, there were 3 i3's parked in the shopping center parking lot next to our apartment, all with degrading CFRP roof top layers. A pre-LCI i3 had had the top layer peeled off and the CF painted black. Another pre-LCI i3 had large chunks of the roof top layer missing. A fairly new LCI i3 had blue duct tape attempting to bind the peeling edges to the roof. The sunlight is particularly brutal here in the tropics. Fortunately, our i3's haven't spent much time outside.

frictioncircle said:
p.s. The wrapped roof does look sharp, alohart!
Thanks! It turned out better than I envisioned.
 
alohart said:
In June, there were 3 i3's parked in the shopping center parking lot next to our apartment, all with degrading CFRP roof top layers.

i3s are pretty common here so I'm going to start checking out the roofs (usually I check out the lighting or am looking for the fuel filler trying to determine year or BEV / REx).

If I had a CFRP roof that was delaminating I'm not sure I'd want it replaced – the thought of a CF repair makes me shudder! :shock:
 
the roof looks great. I was going to do the same, but the shop got to the shark fin and it's riveted in place so they stopped. Did you remove the shark fin or just go around it?

thanks,

JT
 
tongsli said:
the roof looks great. I was going to do the same, but the shop got to the shark fin and it's riveted in place so they stopped. Did you remove the shark fin or just go around it?
I read the procedure for removing the shark fin and decided against doing so because it's glued to the CFRP roof. If it were removed and vinyl film installed, the shark fin would have to be glued to the vinyl film underneath it which wouldn't work. Instead, trim the vinyl film around the shark fin which is what my wrapper did.
 
thanks! I have put https://www.cerakote.com trim coat on the roof for now. But maybe when it wears off I will visit the wrap again. If I do, I'll also try a silver metallic color like yours.

the car is garaged most days.

thanks for the feedback

JT
 
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