Step 1
Stake out the building site. Drive a stake into each corner of the planned corn crib and stretch a carpenter's string between each stake. Orient the building so the long side faces prevailing winds to aid in drying the corn.
Step 2
Dig out the sod at the corners and place cement blocks at the corners. Level the blocks, using a string level, so all are on the same horizontal level at least 4 inches above the ground. Multiple blocks at each corner may be necessary.
Step 3
Build a floor frame of 2-by-6-inch treated lumber. Build a box of the exterior frame by nailing together the 2-by 6-inch boards with two 16d box nails at each corner. Place floor joists, also 2-by-6-inch treated boards, every 16 inches between the two long sides of the floor frame. Nail the joists in place with two 16d box nails on each end.
Step 4
Cover the floor joists with exterior grade 1/2-inch plywood nailed in place with cement coated 8d nails.
Step 5
Build walls with 2-by-4-inch 8-foot-long studs. Build an exterior frame of 2-by-4-inch lumber the same length as the sides of the building and 8 feet tall. Place 2-by-4-inch boards between the exterior frame every 16 inches. Build the wall frames for all four sides but include a door opening in one of the short walls. Nail the wall segments to the floor with 16d common nails.
Step 6
Build the roof of the corn crib. Build a two foot tall extension above one of the long side walls of the corn crib out of 2-by-4-inch lumber. Build an exterior frame of the boards with studs every 16 inches. Nail in place with 16d box nails. Place 2-by-6-inch rafters every 16 inches from the high wall to the low wall creating a sloped roof. Cover the roof with corrugated steel roofing.
Step 7
Side the corn crib. Use 1-by-2-inch or 1-by-4-inch boards placed horizontally around the building. Leave a 1-inch air space between each board.
Step 8
Build a door to fit the door opening left in Step 5. Use 2-by-4-inch boards to build a frame. Cover it with the same sliding material as the walls.