How to Build a Root Cellar on the Slope of a Hill

Across the upper Midwest, little doorways peak out of hillocks, reminders of another time, when farm families made their own cheese and stored autumn vegetables for use during the cold winter months.
Keep root vegetables in their own cool cellar.Keep root vegetables in their own cool cellar.
Root-preserving humidity stays high, and temperatures range from the mid-30s to mid-50s, depending on season and management of these buried cellars. Use the slope of a hill near your home to build an energy-saving, food-preserving room. Recycle railroad ties for the framework of your old-fashioned cool root cellar.

Step 1

Dig a 12-foot semicircle into a hill. Dig deeply enough to make the cellar height about 7 feet deep under the surface of the hill -- dig down on the exposed side if necessary. This larger hole gives you room to work around your cellar as you build it.

Step 2

Level the floor of the cellar with a hand shovel and check it with a large level. Tamp the floor down firmly.

Step 3

Lay out a wall pattern for an 8-foot-deep and 8-foot-wide cellar on the floor, marking corners and snapping a chalk line between them.

Step 4

Lay railroad ties around the perimeter of the cellar, beginning with the back wall. Cut the ties so edges overlap and attach each layer to the one under it with 12-inch tie nails. Leave a 3-foot opening on one side of the front of your cellar.

Step 5

Lay ties around, overlapping, and nailing ends on each course, until your cellar stands tall enough to walk into.

Step 6

Cut to fit and nail an 8-foot-long 2- by-6-inch header across the top of the front wall. This header will tilt the roof back slightly so that water drains away from the doorway.

Step 7

Cut two pieces of 2- by-6 to form the upright frames on either side of the door and nail them into the ends of the ties on either side of the doorway. Fit another piece of 2- by-6 between the frame sides and knock it into place as a threshold.

Step 8

Nail two sheets of plywood across the top of the cellar to make a roof. Nail the plywood down with 8-penny nails. Staple roofing tar paper over the roof, overlapping the seams between the plywood and down around the railroad ties.

Step 9

Cut a hole through the wall near the floor on the open face of the cellar and install a 2-inch PVC pipe through the wall. Drill a second vent on the top of the roof, ending 6 inches above the roof to vent warm air.

Step 10

Backfill the space around the cellar with 2 to 3 feet of gravel. Then backfill with subsoil, leaving 6 to 8 inches space for topsoil.

Step 11

Nail exterior grade foam insulation panel to the roof and cover the roof and sides with topsoil.

Step 12

Fill the inside floor with 3 to 4 inches of gravel, so humidity can percolate up through the soil but can’t muddy the floor. Cut a piece of plywood to fit the door opening and mount it on strap hinges.

Things You Will Need

  • Shovels
  • Fluid or digital level
  • Chalk line
  • Plumb line
  • 60 to 70 6-inch-by-8-inch-by-8-foot railroad ties
  • 12-inch nails
  • 8-penny galvanized nails
  • Hammer
  • Chain saw
  • Circular saw
  • Sledge hammer
  • Foam insulation board
  • 4-penny galvanized nails
  • 4 sheets 1-inch-by-4-foot-by 8-foot plywood
  • Roofing tar paper
  • Strap hinges
  • Galvanized wood screws
  • Gravel

Tips

  • Rent or borrow a little excavator to make short work of digging the cellar. Save the dark topsoil to use on the finished cellar. Seed the covering with grass or native plants to hold the soil in place.
  • Cover the walls inside your cellar with exterior-grade foam board and install deep shelving along the back and sides to store wood or wire baskets of produce.
  • Exterior-grade engineered woods such as LVL may have the same strength as railroad ties but are more expensive. Re-bar might be substituted for 12-inch nails if you have a heavy-duty drill with long, 1/2- or 5/8-inch bits and a metal blade for your jigsaw.

Warnings

  • If you plan to dig deep into a steep hillside, consider renting trench shoring plates for a safe work site.
  • Root cellars can become an attractive nuisance. In addition to sealing the vents with screening or vent covers to discourage rodents, secure the door with a hasp and padlock for security against larger critters.
  • Use preserved lumber for cellars to forestall rot. Railroad ties, available from railroads, generally contain preservatives. However; ask what chemical preservatives have been used and refuse any lumber or ties treated with formaldehyde or arsenic-based preservatives.

About the Author

An avid perennial gardener and old house owner, Laura Reynolds has had careers in teaching and juvenile justice. A retired municipal judgem Reynolds holds a degree in communications from Northern Illinois University. Her six children and stepchildren served as subjects of editorials during her tenure as a local newspaper editor.