We use the term "dense pack" when we are referring to cellulose installed at densities of 4.0 lbs/cuft. The settling and moisture problems of the past have been overcome with the advent of the dense pack cellulose installation technique.
Loose fill cellulose is most often applied in areas with flat, horizontal surfaces. It is perfect for attic insulation, particularly when additional insulation needs to be added. Loose fill cellulose insulation can be added right on top of fiberglass insulation or other insulating materials.