How To Seal A Attic Hatch
There are two issues that need to be addressed with the attic hatch.
How to seal a attic hatch. Air seal the hatch perimeter the plywood hatch rests on a small wood strip lip. If you have pull down attic stairs or an attic door these should be sealed in a similar manner. To guarantee a good seal i paired sash locks with a gasket of foam weather stripping around the frame of the attic hatch. When the sash locks are rotated in use they form an air tight seal with the foam weatherstripping.
My apologies for the lack of photos but you can surely imagine how it works. Air sealing involves two steps. Seal trim to ceiling. Long piece from a batt of unfaced fiberglass insulation and fold it at the bottom of a 13 gallon.
Once you have the materials you can begin to seal and insulate the knee wall access door through these steps. Create air tight seal between hatch and trim. Cut a piece of fiberglass or rigid foam board insulation the same size as the attic hatch and nail or glue it to the back of the hatch. The standard air sealing recommendation is to install a compression bulb weatherstrip.
Weatherstrip the edges and put a piece of rigid foam board insulation on the back of the door. Apply weather stripping to the door to create a seal. Pre made insulated attic stair covers are also available from local home improvement centers or on the web. Plug open stud cavities.
This can also be beefed up to a sealing gasket like the one on your refrigerator door. Treat the attic door like a door to the outside. Apply a bead of caulk on the inside and outside edges of the trim and then reattach it. Plug the big holes first.
Fortunately you can easily air seal and insulate your attic hatch saving you energy and money.