How to Insulate Cellar Doors

Poor insulation causes higher heating and cooling costs inside your home. Keep the cold air out in winter and keep it in during the summer by properly insulating your doors and windows. Outside cellar doors can also allow cold winter air into the home. Although the doors usually enclose the unheated area beneath your house, cold air that gets through emanates through the floorboards and results in a higher heating bill. Insulating these doors, whether you have a traditional door-style cellar opening or a hatch, is done in a similar fashion as insulating any other door in the home.

Spray foam insulation
Adhesive insulation tape
Staple gun
Straw

Instructions

- 1
  Stand inside the cellar with the doors closed and the lights off during the daytime. Locate any cracks where the sunlight shines through to determine where cold air is getting in.
- 2
  Spray expanding foam insulation between any cracks between the door frame and the surrounding walls. Allow the insulation to cure for 24 hours and then inspect the area for any remaining cracks. Apply more insulation as needed.
- 3
  Stick adhesive foam insulation tape around the inside door frame to fill the gap between the door and the frame. Use a foam tape with a thickness slightly greater than the size of the gaps.
- 4
  Reinforce the tape by stapling the ends and corners in place with a staple gun. The adhesive may fail in the cold weather experienced by an exterior cellar door.
- 5
  Cover ground-based hatch-style cellar doors with a thick 6-inch layer of straw during the winter months to insulate them from the cold outdoor air. If winter access is necessary, place the straw in a bag and cover the door. Simply remove the bag when accessing the cellar, and replace it afterward.

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