Air seal the trim the first step is air sealing the finish trim and enclosure around the attic hatch.
How to seal attic access panel.
Cut 1 3 boards to fit the perimeter of the opening and nail them on with 6d finish nails.
If your hatch rests directly on the moldings add 2 1 2 inch wide stops around the opening.
Install weather stripping along the top of this ledge.
How to insulate and air seal an attic access hatch.
The access panel will rest on this trim.
Once you have the materials you can begin to seal and insulate the knee wall access door through these steps.
The trim should extend one half inch to one inch around the inside edge of the access hole forming a ledge.
Seal the attic access weatherstrip the attic access hatch or door.
Apply weather stripping to the door to create a seal.
Sealing the attic hatch or door finish up by sealing the access hatch with self sticking weather stripping.
Carefully pull down the finish trim.
The stops provide a wider surface for attaching the weatherstrip and a space to mount hook and eye fasteners.
Install wood trim pieces on the ceiling side of attic access hole framing.
Use spray foam to air seal these openings if they exist.
Pray that the installer used finish nails and not say ring shank nails.