If your hatch rests directly on the moldings add 2 1 2 inch wide stops around the opening.
How to seal attic access hatch.
Affix foam insulation to.
The insulation will both slow heat loss and add ballast to the hatch to improve the seal at the weatherstripping.
From inside the attic check for any openings holes or fenestrations into the knee wall surrounding area.
Air seal the trim the first step is air sealing the finish trim and enclosure around the attic hatch.
How to insulate and air seal an attic access hatch.
Apply self adhesive foam weatherstrip tape to the top edge of the stop.
Seal the attic access.
Pray that the installer used finish nails and not say ring shank nails.
Cut four pieces of polystyrene rigid insulation about 1 2 inch smaller than the dimensions of the hatch.
Remove your existing attic hatch and measure its size.
Use spray foam to air seal these.
Cut 1 3 boards to fit the perimeter of the opening and nail them on with 6d finish nails.
Apply weather stripping to the door to create a seal.
Carefully pull down the finish trim.
Weatherstrip the attic access hatch or door.
How to seal knee wall doors.