I am putting in a shower/tub unit (fiberglass). It is going on top of a cement floor. I figured that i should insulate between the floor and the tub or if someone wants to take a bath, much heat will escape. What should I do this with? Foam I imagine but is there a specific process?

It was suggested by the Zipcode site that I need an R-49 insulation in my unheated attic area and R-13 in the wall of our unfinished upstairs of our Cape. We are currently finishing this area. We were told we could not put anything greater than an R-15 in the area between what will be our bedroom ceiling and the attic floor due to the plywood floor we put on top of our rafters above our upstairs bedrooms to create an attic floor. We were also told that we could not insulate the roof peak because it would not be a heated space. My question would be, is it true that we cannot insulate our roof peak, even if properly vented, and why? And are there any products designed to provide a higher r-value than batting insulation that would be thinner than regular batting insulation (that can be fit in between the ceiling of our to-be bedrooms and floor of the attic)? Do we use faced or unfaced batts in either walls or ceiling? Thank you for your time, Cathy