I just finished gutting my 13' Scamp
. The older ones had vinyl-covered Ensolite foam, whereas the new ones have "fuzzy stuff" over reflective bubbles, like your rig. I'm going to try attaching 3/16" cork sheet. The plan is to stain it with whitewash stain, then cover it with three coats of polyurethane.
Besides cost and availability, there's another reason those reflective bubbles are there. Heat from sunlight goes right through fiberglass shells. Before the cork goes on, I'm going to paint
the inside with white reflective roof paint
. I'm not familiar with all of the various formulations of that stuff, but most are heavy-bodied acrylic paint
with either aluminum flakes or glass microspheres. (Mine contains the microspheres.)The old Ensolite-lined Scamp
can be a real oven in direct sunlight. When you can't spare an inch or more for insulation, the reflective barrier is the way to go. In fact, a reflective barrier + insulation is even better, whether in house or RV. Just my $0.02 worth.