How to Make a Root Cellar When Building a New Basement

Site the root cellar in the northeast corner of the basement, in front of a window, if possible. This location does not receive direct sun, except in the morning, which will help moderate the interior temperature of the root cellar. The window will make it easier to vent the root cellar; such venting is necessary to keep the root cellar's temperature in the correct range.

Draw a line on the concrete floor, using a marker, indicating the placement of the interior walls and door of the root cellar.

Glue pressure treated 2-by-4 studs on the floor at the locations of the root cellar's walls. Orient the 2-by-4s so the wide, flat side is against the floor, using construction adhesive. Attach another 2-by-4 to the corresponding spots on the ceiling studs using 3-inch wood screws. These are the top and bottom plates, respectively, of the root cellar's interior walls.

Build the interior walls of the root cellar, using standard 2-by-4 lumber set 16 inches apart. Although the studs can be farther apart than is normal in standard construction because they are not load-bearing, a 16-inch space between the 2-by-4s will make installing the insulation easier. Measure the height of the gap from the floor to the ceiling plates for each 2-by-4 before cutting. Insert the stud between the bottom and top plates you installed in Step 3. Nail the 2-by-4 to the top and bottom plates with 3-inch nails driven in at an angle so they secure the wall studs to the top and bottom plates.

Install mold-resistant drywall or blueboard (used instead of drywall in showers and bathrooms) to the interior side of the root cellar's walls. Attach the drywall or blueboard to the studs using galvanized drywall screws.

Remove the glass from the root cellar's window. Glue a piece of plywood to either side of a piece of rigid foam insulation the same size as the glass you removed from the window. Drill two holes in the window, evenly spaced, in which to run the ventilation pipes. Make the holes the same size as the outside diameter of the polyvinyl chloride (PVC) pipes you will use for the root cellar's ventilation system.

Insert a 12-inch length of PVC pipe into one of the holes you drilled in Step 6. This pipe will draw warm air out of the root cellar. Attach a shutoff valve to the inside end of the pipe.

Insert a second 12-inch length of PVC pipe into the other hole in the plywood-insulation sandwich you made in Step 6. Attach a 90 degree turn to the inside end of the pipe. Attach another PVC pipe to the other end of the 90 degree turn. Cut this pipe so its end will be about 6 to 12 inches above the floor. Put a shutoff valve onto the end of the pipe that is nearest the floor. This pipe will draw in cool air from outside, as long as the outside air temperature remains colder than the temperature inside the root cellar.

Insulate the interior walls of the root cellar by putting rigid foam insulation between the studs on the side of the root cellar's interior walls that faces the basement. This will also help prevent mold from forming on the insulation because the air in the basement will be less humid than the air in the root cellar. Glue the insulation to the back of the interior walls' mold-proof drywall or blueboard, between the studs, using construction adhesive.

Glue insulation to the outside of the root cellar's door, using construction adhesive. Cut out the areas for the door's hinges and doorknob before gluing the insulation to the door. Install the door for the root cellar by attaching the hinges first to the door, then to the doorjamb.

Insulate the ceiling of the root cellar (which is the underside of the subfloor of the dwelling's first level). Glue rigid foam board insulation between the ceiling (floor) joists using construction adhesive.

Seal all small cracks, holes or other gaps in the root cellar's walls, ceiling and door using expanding foam caulk. Also apply caulk to the vent pipes where they are attached to the plywood window insert.

Hang metal shelf brackets from the ceiling of the root cellar. Position the shelf brackets to leave a gap between the back of the shelves and the wall of approximately 1/2 to 2 inches when the shelves are installed. This gap will help air circulate around the shelves, extending the storage life of the produce you store in your root cellar. Attach shelves made of 2-by-12-inch lumber to the metal shelf brackets.