Abstract: A cover for closing an access opening that leads to an infrequently used space within a building, such as an attic, provides thermal and acoustic insulation at the access opening. The cover may be in one or two portions, including a closure alone or a closure and a frame having an aperture that can be closed by engagement between the closure and the frame. When the cover is used alone it engages a frame or a wall circumscribing the access opening. The cover is sized and shaped to close a stairwell, or the opening at one end of a stairway, or an opening in a generally vertical wall that is not necessarily associated with a stairway. The closure and frame are each made of one or more components.