it was rotten and had separated from the firewall. The cause was a leaking watertank, also battery acid did some damage too. After removing all the vinyl the floor looked like Swiss cheese. I replaced the part that was most damaged.
The windows were letting in water too I found out, so new acrilyc and moulding was necessary.
It took me 3 days to fix the problem. The worst job so far, but together with new sunscreens it was well worth the effort, a clear view to the outside world.
