Hi, first time poster, since I just got my 75' 914-4 2.0 a month ago.
Car runs and drives, but is cosmetically ugly, it was originally copper, but one of the previous owners painted over the copper to make it look green, now the green paint is falling off.

ANYWAY!

My intention is to drive it around with spartan interiors, just the essentials, no carpets and barely any electronics to keep it simple and fewer things that can go wrong since my goal is reliability (yes, it's a daily driver).

So this past weekend I started gutting the interior and removing all the carpets, expecting to find metal panels that I would look closely at for rust damage and evaluate if I they were going to need to get replaced or repaired or what..

to my surprise, I did not find metal, I found what I believe is fiberglass or some type of cardboard panel covered in resin. It looks like one of the previous owners laid up fiberglass over the metal panels, either to protect them from rust, or to cover all the rust spots that were already there.
Click to view attachment


I tried searching for info on this already to no avail, looks like it's not common practice.
Has anyone else seen this done before? Should I be worried? what would you recommend as a path forward?

That is tar sheets over the sheet metal floors. that is from the factory, and your floors look good!

That looks like the factory "tar" coating. You can scrape it off (heat guns help) to check for rust underneath.
Lots of posts about this...

Sound proofing tar sheets, applied at the factory.

They can crack and let water through, especially near the rear firewall which results in rust under the tar.

Do a search here, there's plenty of threads on the subject ...


PS:

Thanks for the quick respone guys!
Now I feel dumb because I knew about the tar sheets, I just didn't know what they looked like.

What made me think it was fiberglass was because of what I also found in the rear trunk:
Click to view attachment
Click to view attachment

I'm pretty sure that IS fiberglass on top of rust, or is it some other kind of obvious sound deadening that I didn't know was supposed to be there?

Yep, that would be some DAPO's "fix" for a rusted trunk floor ...

DAPO's??

Dumb Ass Previous Owner(s)

Fiberglass bonds to the rust but dose not stop the rust, eventualy it will delaminate. As you can see in the trunk. Once I thought I had a rust free driver, went over a bump and the battery tray fell. DAPO, sheet metal screws don't work in fiberglass. Hole floor and half of the fire wall and passenger inner fender well was done. Driver seat rails were coming out the bottom of the floors when I cut the car up.

what color is your car? it looks like Copper Metallic(L99K)!

If it is Copper and Green just call it The Bad Penny and it.

Posted before, but if you want to remove use dry ice

https://youtu.be/Eesr-AcQzNw

Interesting approach with the dry ice and IPA.

I cleaned/removed both sides in less than 30min
with a oscillating multi tool and scraper blade (see
Link). The clean up was extremely easy and dry.

https://m.harborfreight.com/multi-tool-blad...3-pc-61827.html