There is a 3'x3' opening in the ceiling of my second (top) floor. The opening leads into the unheated attic. I want to both seal and insulate this opening to keep out the cold in the winter. (I live in New York, were it can get cold.) I already have built a box around the fan in the attic using hard pink insulation, But it does not seal perfectly and is not all that well insulated.
How might I secure a 2"x3'x3' box to the underside of the opening (i.e., in my second floor hallway)? The box would contain 1.5" hard, pink insulation in this box and would have a 1/2" cover framed with 1"x2".
How might I attach this to the ceiling so that it will be a tight fit but easy to take off in the spring?
P.S. These related posts do not cover this question.
How do I insulate a whole-house fan during the winter?
Air sealing a whole house fan