Underground shelter

[Guest Hoppy]

If you are making a storm shelter, consider taking a few extra simple steps and make it a fallout shelter too. You need at least 3' of loose soil or 2' of solid concrete to block 99.9% of radioactivity from fallout. I won't go into complete design issues such as ventilation or water, but the mass around the shelter is important. If you have one complete side open in a shelter built into a hillside, then keep enough filled sandbags inside the shelter to stack against the door or wall to create the 3' of soil needed. You can remove these when it is time to leave. Remember, cinder blocks are not the same as solid concrete. Even core filled blocks still have less dense areas that can allow radiation to penetrate through easily.

I hope this helps.