I'm planning to rewallpaper a 1940 house that has two layers of wallpaper over some sort of gray wall felt. My cat damaged one corner of the wallpaper down through the felt. Can I just try and remove the old wallpaper and leave the damaged felt in place or should I strip all of it off? The walls are not plastered underneath the felt, just wood. Would a heavy paper made for covering up irregular surfaces work? I don't want to start until I've got a clear idea of what to do.