Air seal the trim the first step is air sealing the finish trim and enclosure around the attic hatch.
How to seal attic access hatch.
If your hatch rests directly on the moldings add 2 1 2 inch wide stops around the opening.
Sealing the attic hatch or door finish up by sealing the access hatch with self sticking weather stripping.
Weatherstrip the attic access hatch or door.
Cut 1 3 boards to fit the perimeter of the opening and nail them on with 6d finish nails.
Seal the attic access.
Pray that the installer used finish nails and not say ring shank nails.
Apply self adhesive foam weatherstrip tape to the top edge of the stop.
From inside the attic check for any openings holes or fenestrations into the knee wall surrounding area.
Affix foam insulation to.
Use spray foam to air seal these.
The insulation will both slow heat loss and add ballast to the hatch to improve the seal at the weatherstripping.
How to seal knee wall doors.
Cut four pieces of polystyrene rigid insulation about 1 2 inch smaller than the dimensions of the hatch.
The stops provide a wider surface for attaching the weatherstrip and a space to mount hook and eye fasteners.
Apply weather stripping to the door to create a seal.
The latch should lay flush against the frame.