On the third floor of my house (attic), there is a small bedroom that has been made with two doors in it - 1 door is a closet and the 2nd door opens into the "attic" where the bulk insulation is. What is in there is wrong. The rafters are sealed up tight with fiberglass that has a black and firmer, heavier side facing the warm part of the house. There is no insulation under the floor from what I can tell by looking into a few decent sized cracks and holes. Also, the straight wall next to what is the small bedroom does not have any insulation on it.

I had Home Depot come by and take a look and for them to do everything - it would be an expense of about $2700 including the removal of all of the stuff in the rafters and to cut 4' x 4' chunks in the floor to blow in R19 (which, I don't think is enough - I'm thinking a minimum of R38 if not R76 by doubling it). We live in NJ - it gets cold in the winter and hot in the summer. My wife and I would like to do as much of this as possible but the take down and disposal of the old stuff seems to be a project which will be a royal pain.

Assuming there is no insulation of any kind under the floor, can you just lay out insulation rolls on top of the floor or does it have to go in between the joists? Is there any harm if you have insulation on top of a flat wood surface, 4-6" of space, more wood below that?

Anyone have any suggestions on what they would do? I believe the square footage of the floor was around 320 SF - give or take.