Original under carpet soundproofing?

[Clifford3051]

Good morning all
I know people have used various soundproofing when restoring their cars but what was the original floor soundproofing under the carpets when it came out of the factory?
Thank you.
C

[WestonE]

It was water holding felt with a bitumen layer to hold it together. It is a disaster once it gets wet because it holds water against the floor that then gets through the cracked factory anti drum sheets and rots the floor inside out. It can also go spectacularly moldy make the interior small nasty. Use it for a template on closed cell foam under the carpet and save yourself a lot of trouble.

Eric