Underground survival shelters were first popularised during the cold war as a response to the threat of a nuclear attack; however they are not exclusively limited to that one emergency. Underground survival shelters can be used for a plethora of different emergencies. For example, in the middle of an earthquake the underground survival shelter can be used to avoid hazards from falling or shaking objects. Underground survival shelters can also be used as a panic room in the event of a home invasion. Building your own underground survival shelter can be costly but not impossible.
Measure your container's width and length. Dig a hole at least two feet deeper than the shipping container's height. When digging the hole give it at least one foot of length from the shipping container at all sides and at least four feet away from the door. This can be done manually with a shovel, but doing it with a back hoe will save a great amount of time.
Move your shipping container into your hole by towing it in with your truck. If you do not have access to a truck that will allow you to do this, you can hire a septic tank company to move the container into the hole for you. It should have a foot of room on the sides and four feet on the door side.
Build steps out of the concrete blocks until you've built a stairway from the bottom of the door to the top of the opening.
Use the back hoe to level the banks of the dirt to be even with the container's top. Set two eye beams on either side of the steps making sure they're level with the top of the container.
Lay at least four pieces of frame wood across the container stretching from bank to bank. Lay wood on top of those facing the opposite direction and nail them down to create a frame. Lay your sheets of corrugated metal across this to create the roof of the shelter making sure not to obscure the opening of the shipping container. Leave two 12 inch openings in between the sheets of corrugated metal.
Create bracing out of 2x4's by nailing one piece horizontally along three vertical pieces. Create three of these braces and place two of them underneath the corrugated metal on either side and place one inside the shipping container. These will act as temporary bracing.
Cut a 12 inch hole in the centre of each of the openings you left between the corrugated metal sheets on the roof of the shipping container. Place one 12 inch pipe inside each of these holes. These pipes will act as air vents.
Place concrete blocks along the sides and back of the container and place your rebar inside of them; this will add structure to your concrete. Pour concrete into the three sides, excluding the doorway and stairs. Continue pouring until each side, as well as the corrugated metal on the roof (excluding the 12 inch pipes), is covered with six inches of solid concrete. Extend your stairway to the top of the hole again using your concrete blocks.
Use your backhoe to cover everything, except for the doorway, with soil.
Pouring concrete into the blocks holding the rebar helps hold the bars in place, but isn't absolutely necessary.
Do not pour concrete into the plastic poles as this could obstruct the air from coming in and out of the shelter.