here goes
you have the foam backed material then the board that it glues to
above that you have a cardboard based material sandwhiched between the framework and the sheetmetal .....the sheetmetal of the roof is NOT primed and when removed mine showed signs of surface rust ......removal is a pita as it was fitted at time of manufacture ,have to break it up to remove
suggest anyone that removes the lining also remove the cardbaord and treat the surface rust