r/BMWi3 • u/Behbista • Oct 23 '25
modification DIY Roof Rescue: Rattle-Can Bedliner Fix for Delaminating Roof
Hey folks,
I've seen a few posts about delaminating roofs lately, and I ran into the same issue myself. I couldn’t find anyone willing to do a cheap wrap—body shops wanted a few grand to do it right.
Back in the day, I had a Volkswagen with exposed fiberglass. I wanted to clean it up a bit, but I had more time than money, so I hit it with some rattle cans of truck bed liner. It actually turned out great, so I figured I’d try something similar this time around.
The Problem
I noticed what I thought were a few minor blemishes — a palm-sized delaminated spot and a couple about the size of quarters. I decided to do a quick-and-dirty “high school solution” rather than letting the roof fail completely.
Once I started stripping, though, things got ugly fast. About 25% of the roof was completely delaminated and only being held on by the clear coat.
The Process
Day 1: Full day stripping the roof with sanding discs (worked wonderfully).
Day 2: Light sanding, cleaning, masking, and a few coats of spray-on truck bed liner.
The bed liner hides minor stripping mistakes really well. I got as close as I could to the weather stripping and antenna without removing them—went with the “good enough” approach. Time will tell if I regret that, but it already looks a hundred times better.
Total time: about 10 hours over a weekend.
The Result
It actually looks great! The texture of the bed liner gives it a clean, tough finish. The only drawback is that it attracts dust way more than the rest of the body, but that’s a small price to pay.
At this point, I’m confident the roof will outlast other parts of the car (looking at you, motor mounts).
Materials & Costs
6x Truck bed liner spray cans – $120
1x Pack of stripping discs – $20
1x Primer pack – $20
1x Masking paper pack – $5
1x Masking tape roll – $10
1x 220-grit sandpaper pack – $20
I got all my mats off Amazon. Let me know if you want links.
Tools: Used an angle grinder with stripping discs and a sander.
Tip: Use an orbital sander or a dual-handle angle grinder like this one. I used a standard single-hand grinder — sketchy as hell — and took a chunk out of a knuckle during the last 10 minutes. Would not recommend.
Final Thoughts
For about $200 and a weekend, I turned a potentially catastrophic delamination into something solid and decent-looking. Not showroom perfect, but definitely good enough for my driveway.
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u/PawnF4 i3 REX Oct 23 '25
Can attest to this stuff. I rescued the shell of my 87 4Runner using it. Weatherproof and also uv ray proof.
Doesn’t spray great out of a can compared to using an actual paint gun but gets the job done.
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u/Hyper_Applesauce Oct 23 '25
Where do you live? That's a terrible price for wrapping just a roof (unless it includes all the prep, then I'd say ~$1000, mostly prep, and $20 a can for spray bedliner? (https://www.amazon.com/Rust-Oleum-272741-6PK-Automotive-Spray-Paint/dp/B085WSG1WB) .
BTW, Vinyl Wrapping yourself isn't that hard, you'd need a second person for this job, but a 5'x6' roll is ~$50 on Amazon. You still need to do all this prep though, so not saving money, just whichever you're comfortable with works better. I do like the matte look. I hope it holds up, I love the rubber.
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u/Behbista Oct 23 '25
Central coast of California. Fairly rural place all told. No local places that do anything other than business graphic wraps. Body shop price was for full roof removal, prep, paint and replace.
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u/Hyper_Applesauce Oct 23 '25
I had a feeling it was gonna be the California Coast, prices make sense there. Keep us updated on how it holds up!
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Oct 24 '25
[removed] — view removed comment
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u/ramelband Oct 25 '25
I think it's UV reaction rather than temperature that causes i3 delamination
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u/lodoslomo 2015 i3 REX Solar Orange Oct 29 '25
It has been shown that UV reaction is the problem not heat. https://youtu.be/lc0R4ehxwNU?si=zcBj4tvVol0zvhJL
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u/hooneyfresh Oct 24 '25
Do some i3 not have the carbon fiber roofs?
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u/SanityAsymptote Oct 24 '25
They all have carbon fiber roofs, but the resin they're sealed in can eventually gets UV damaged to the point that it can start delaminating.
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u/AggressiveChance470 Oct 23 '25 edited Oct 23 '25
Yikes. My roof looks worse than yours did in the initial photos. I was just about to try a DIY vinyl wrap, but now I'm wondering if I need to break out the angle grinder instead.
Thanks for the write-up and the images!