My 100+ year old house has an unfinished attic with no attic insulation at all. The floor is covered with old tongue & groove floor boards - there is no insulation betwen the floorboards and the ceiling below. The ceiling is just exposed rafters and roof deck. I know I need to insulate but do not want to pull up the attic floor so am looking to insulate the roof. Fiberglass batts or foam or cellulose seem messy and expensive. I recently read about SuperTherm ceramic insulation that can be sprayed on or applied with a paint roller. It's only a few mils thick and one coat supposedly gives an R-20. Has anyone ever used this material? Can it be used on the interior of an unfinished attic? This seems like a great product. Are there any disadvantages?