How to Build a Food Storage Cellar

A food storage cellar, or root cellar, is an underground room that maintains a consistent and cool temperature based on the temperature of the ground. In addition, the open dirt floor allows for darkness and moist air, which is ideal for most vegetable storage. In times past, it was the primary way to store vegetables and other items that needed cooler temperatures. A root cellar can be as simple as an old ice chest buried in the ground and people have used all manner of materials and methods to form the walls. This article will outline how to build a root cellar using concrete blocks.

Shovel
Excavator, tractor or backhoe
8-by-8-by-16-inch concrete cinder blocks--number determined by the size of the cellar (for a 12-by-12-foot cellar, you would need roughly 400 blocks)
Fiberglass impregnated concrete bonding agent or concrete mortar
4-by-8-foot roof beams
2-by-8-foot for blocking between the beams
Black plastic (6 mil or heavier)
9 sheets 3/4-inch plywood or OSB
6 feet of 2-inch PVC pipe
1 2-inch PVC 90-degree elbow

Instructions

- 1
  Choose where you want the root cellar located and decide how large a room you want. Dig a hole that will be two to three times larger on all sides so you have room to work. A tractor, backhoe or excavator make quick work of this project.
- 2
  Mark and square your corners. Lay out string lines and place your first row of concrete blocks. Stack the blocks to build the walls to about 7 feet, which takes 11 rows of standard cinder blocks, offsetting each row so the vertical seams don't line up. Coat the exterior walls with a fiberglass-impregnated concrete bonding agent. This provides a watertight seal and locks the blocks together more securely than filling them with more concrete. Allow the bonding agent to cure.
  
  An alternative to this is to mortar the blocks together and then coat them with a concrete sealer. However, this is much slower, and has no greater strength.
- 3
  Place 4-by-8 beams across the roof every two feet. Secure the beams to the concrete blocks using ties and concrete fasteners. Install 2-by-8 blocking between the beams at the edge of the structure, securing them by driving nails at an angle into the beams. Sheet the beams with two layers of 3/4-inch plywood. Seal the roof with a heavy-duty, foundation-type sealing compound. Then place heavy black plastic (6 mil or more) over the roof to provide an extra layer of moisture protection.
- 4
  Carefully back fill all sides of the structure, doing a little on each side, then working your way around. Keep the pressure even on all sides, or the force of the soil can actually push the structure to an angle. Cover the roof preferably to a depth of two feet of soil. Plant grass to hold the soil in place.
- 5
  Frame in the doorway and install a well-insulated door. Ideally, you would build a short tunnel at the doorway and install two doors, creating an airlock for even better temperature control; however, this is not a requirement.
- 6
  Install a simple vent to allow air flow in the cellar to prevent mold and mildew from forming and keep the air relatively fresh. Using two-inch PVC pipe, run the pipe out the top of the cellar with the air deposited at the bottom of the cellar.
- 7
  Install shelves and bins for food storage. It's also a good idea to either run a power line and install a light or place a battery-operated lantern inside the door for visibility.

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