I have a old single-story home that has exposed floor joists on the first floor. Because of this architectural feature my attic has a flat floor on which I would like to put insulation. With the winter season approaching I need to put insulation in now because there currently is none. My concern is that I will have to walk up there from time to time as we renovate different areas of the house. Would it be better to put fiberglass down that can be moved out of the way if necessary or dense packed cellulose? Which one can I walk on?