[Mikendebbie]

The black fabric bottom is probably darco fabric. The tan material is probably a piece of filon similar to the sides of the RV. Are you the original owner? If you are - maybe the day your slide was made they ran out of darco, but had a pile of scrap filon and glued it up to the bottom...just my theory - I really don't know how it got there. I think I recall one other instance recently where someone apparently had cream colored filon on the bottom of a slide.

In the FILES section (brown strip above on this page) you will find UMHV darco fix by ChuckS. You install the strips to go over the rollers and the darco will not degrade anymore due to running back and forth over the rollers. You can add them to the filon also. The screws are counter-sunk into the UMHV. The write-up shows screw sizes to use. Lots of folks here on the forum have added the strips with good results.