Repairing Carbon Fiber Roof

Hey all, so yesterday I got a car wash and I came to look at my car and I was shocked. I knew there was a tiny little cracked in the roof, but this is what happened. (See picture). The crack was extremely small, as in smaller than a peddle, and now is a 3 inch scrape in the roof. The clear coat cracked and pieces of it broke off. I went to a body shop today that specializes in carbon fiber work and they said that when enough water gets into a crack like that. It works under the clear coat and breaks it. They gave me two options: replace the whole clear coat and the rubber moldings at the top of the front windshield and rear window ($2600) or have them just try and match it by spraying it themselves to patch the spot ($450). These options are pretty damn expensive for what I thought was just a tiny crack. Has anyone experienced something like this before and what's the best and cheapest way to get this replaced?

I had this same exact problem, except mine looked more circular. I claimed mine under insurance due to bird poo (which was what caused the initial break through the clear). But my other options were to try and replace the clear, where I was quoted $350 or so. Or just replace the entire roof. The entire cost of replacing the roof through insurance had they not covered it was around $2500 or so?

Youngh wrote

I had this same exact problem, except mine looked more circular. I claimed mine under insurance due to bird poo (which was what caused the initial break through the clear). But my other options were to try and replace the clear, where I was quoted $350 or so. Or just replace the entire roof. The entire cost of replacing the roof through insurance had they not covered it was around $2500 or so?

Yeah that's what I'm dealing with. I have a warranty, but I just recently had them replace my second throttle actuator which went out last week. I'm afraid they'll say something along the lines of "the crack was already there before you got the warranty." Or they'll just void my warranty because of their suspicions that I'm having too much covered in such a short amount of time. I really don't want to pay $450 for such a small, yet noticeable spot, but I also don't want to damage the roof any more than it is. I also don't want to wait so the warranty company doesn't suspect something fishy because then that part of the roof could get more damaged

RosieTheRedM3 wrote

Yeah that's what I'm dealing with. I have a warranty, but I just recently had them replace my second throttle actuator which went out last week. I'm afraid they'll say something along the lines of "the crack was already there before you got the warranty." Or they'll just void my warranty because of their suspicions that I'm having too much covered in such a short amount of time. I really don't want to pay $450 for such a small, yet noticeable spot, but I also don't want to damage the roof any more than it is. I also don't want to wait so the warranty company doesn't suspect something fishy because then that part of the roof could get more damaged

I just replaced mine!!!
Cost - $4500.00

Cbozz wrote

RosieTheRedM3 wrote

Yeah that's what I'm dealing with. I have a warranty, but I just recently had them replace my second throttle actuator which went out last week. I'm afraid they'll say something along the lines of "the crack was already there before you got the warranty." Or they'll just void my warranty because of their suspicions that I'm having too much covered in such a short amount of time. I really don't want to pay $450 for such a small, yet noticeable spot, but I also don't want to damage the roof any more than it is. I also don't want to wait so the warranty company doesn't suspect something fishy because then that part of the roof could get more damaged

I just replaced mine!!!
Cost - $4500.00

Ouch what was the reason you had to replace. Too much sun time? Something hit the roof? I park my car outdoors at my work which makes me cry so am paranoid what a couple hot summers will do to it and thinking what I can do to maintain it.

Cbozz wrote

RosieTheRedM3 wrote

Yeah that's what I'm dealing with. I have a warranty, but I just recently had them replace my second throttle actuator which went out last week. I'm afraid they'll say something along the lines of "the crack was already there before you got the warranty." Or they'll just void my warranty because of their suspicions that I'm having too much covered in such a short amount of time. I really don't want to pay $450 for such a small, yet noticeable spot, but I also don't want to damage the roof any more than it is. I also don't want to wait so the warranty company doesn't suspect something fishy because then that part of the roof could get more damaged

I just replaced mine!!!
Cost - $4500.00

Damn did you have to replace the carbon fiber too? Why so much?

m3jala wrote

Ouch what was the reason you had to replace. Too much sun time? Something hit the roof? I park my car outdoors at my work which makes me cry so am paranoid what a couple hot summers will do to it and thinking what I can do to maintain it.

I had a chemical cleaner spill on it. dried out and ate up the resin.
here are pictures:






new roof OEM BMW



new roof in its glory



I also upgraded headliner to alcantara

RosieTheRedM3 wrote

Hey all, so yesterday I got a car wash and I came to look at my car and I was shocked. I knew there was a tiny little cracked in the roof, but this is what happened. (See picture). The crack was extremely small, as in smaller than a peddle, and now is a 3 inch scrape in the roof. The clear coat cracked and pieces of it broke off. I went to a body shop today that specializes in carbon fiber work and they said that when enough water gets into a crack like that. It works under the clear coat and breaks it. They gave me two options: replace the whole clear coat and the rubber moldings at the top of the front windshield and rear window ($2600) or have them just try and match it by spraying it themselves to patch the spot ($450). These options are pretty damn expensive for what I thought was just a tiny crack. Has anyone experienced something like this before and what's the best and cheapest way to get this replaced?

That's repairable can you wet sand and have you ever used resin?

last1left wrote

That's repairable can you wet sand and have you ever used resin?

I spoke to BMW and they didn't recommend it, also no painter wanted to work with it. So I had to replace. Look above

Cbozz wrote

m3jala wrote

Ouch what was the reason you had to replace. Too much sun time? Something hit the roof? I park my car outdoors at my work which makes me cry so am paranoid what a couple hot summers will do to it and thinking what I can do to maintain it.

I had a chemical cleaner spill on it. dried out and ate up the resin.
here are pictures:






new roof OEM BMW



new roof in its glory



I also upgraded headliner to alcantara

That does look great! And the alcantara looks really clean too

Yeah, I've heard that a lot of places likely won't take the job because the roofs are finicky. I'd at least try and get another quote from a reputable German/Euro indie shop.

SoCalRPM wrote

Yeah, I've heard that a lot of places likely won't take the job because the roofs are finicky. Is at least try and get another quote from a reputable German/Euro indie shop.

I've considered that already so I'll try tomorrow

Sorry for the spent money but it sure looks nice now!

Cbozz wrote

m3jala wrote

Ouch what was the reason you had to replace. Too much sun time? Something hit the roof? I park my car outdoors at my work which makes me cry so am paranoid what a couple hot summers will do to it and thinking what I can do to maintain it.

I had a chemical cleaner spill on it. dried out and ate up the resin.
here are pictures:






new roof OEM BMW



new roof in its glory



I also upgraded headliner to alcantara

What shop replaced it? I have a sunroof and want to swap the roof with Carbon Fiber

Here's someone selling one off a wrecked car for $1k - https://losangeles.craigslist.org/sfv/pts/d/e92-m3-oem-carbon-fiber-1x1/6651439176.html

Don't know what kind of work is required to get that onto another car, but might be worth checking into...

You need to buy a new roof panel from bmw, it’s very difficult to seperate a bonded roof from the body without damaging it.

amrazM wrote

You need to buy a new roof panel from bmw, it’s very difficult to seperate a bonded roof from the body without damaging it.

Actually it isn’t! My shop did it and didn’t crack anything or chip any part of the old roof. I actually was thinking about selling it for couple of hundred bucks... just the shipping would be crazy because of the size... also the condition of it

Cbozz wrote

I had a chemical cleaner spill on it. dried out and ate up the resin.
here are pictures:

WOW ! But I really wonder, how can you get chemical cleaner on your CF roof ?

///M Power-Belgium wrote

WOW ! But I really wonder, how can you get chemical cleaner on your CF roof ?

It was an accident where I parked the car near a condominium which had their roof pressure cleaned and that did it. I didn’t notice right away and didn’t clean the car....

Cbozz wrote

It was an accident where I parked the car near a condominium which had their roof pressure cleaned and that did it. I didn’t notice right away and didn’t clean the car....

I see . That's really bad luck ! You didn't file a complaint ?
You could show them the pics of your roof ...

amrazM wrote

You need to buy a new roof panel from bmw, it’s very difficult to seperate a bonded roof from the body without damaging it.

I was told that they could just respray over the damaged area (the $450 option). I definitely don't need an entirely new roof. The place I went to specializes in carbon fiber and they are able to get the clear coat off without destroying the carbon fiber (the $2600 option). I'm not sure how they do it but they should me their carbon fiber repairs and creations and I trust them.

I just had a similar issue occur. A reputable body shop quoted $800 to sand off the gel coat and respray the whole roof with clear. They are aware the original is not cleared, but have experience with carbon fiber and most importantly offer a warranty. They said they are confident it will hold up. They said they've seen this issue before and unless it's an isolated issue with chemical cleaner like above or specific damage, that it's indicative of upcoming failure for the whole gel coat (root cause being sun damage). I have always taken great care of my roof with regular washes, sealant/wax, and recently ceramic coat, but it spends its whole life outdoors. I haven't made a decision yet though. Looking at vinyl wrap as another option.

And if you're really adventurous and/or have equipment on hand, you could DIY it per this thread:

https://www.m3post.com/forums/showthread.php?t=1406986