29 interior living space

How to Build a Fallout Shelter

Step 1: Design, Engineer and Research

00 8x16 Shelter Overview

We’ve designed this fallout shelter concept using an adapted rule of three for survival. We know that humans can’t survive blast pressures for more than 3 seconds, live without air for more than 3 minutes, survive in extreme exposure conditions for more than 3 hours, live without water for 3 days, or food for more than 30 days.

So in the order of priority our shelter design must provide:

  1. Ample blast protection from a relatively close nuclear blast as well as explosives that might be used by raiders during the aftermath.
  2. Air intake and exhaust vents to provide a constant flow of air through the shelter.
  3. Adequate protection from external temperature extremes without any dependence on external energy systems.
  4. Ample water for at least a 28-day stay would need to be pre-positioned inside the shelter.
  5. Ample food for a 28-day stay should also be pre-positioned inside the shelter.
  6. Ironically the last item on our list is protection from radiation. To effectively protect yourself from fallout, your shelter needs to be underground and covered with at least three to eight feet of compacted earth – more depth provides more protection.

Since fallout shelters can also be used for other things like, storm shelters, safe rooms, store rooms, guest rooms, and home offices, it’s important to consider these options when designing your shelter. For example, to make your shelter more easily accessible you might want to build a 68-degree ships ladder, true staircase, or position it adjacent to a basement. A vertical shaft, like the one shown in our design, is not conducive to regular easy access.

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24 thoughts on “How to Build a Fallout Shelter

  1. Jane

    Error msg when I attempt to access any additional pages- says there are too many redirects to make a connection.

  2. George.singleton

    Me and my mum been watching Syria on the news and were thinking could be world war 3 so I thought I really want a underground fallout shelter and also fallout new vegas got me into nukes and stuff but I want a proper birds eye view easy design anyone help

  3. jenn

    I’m thinking about building a large log home n sealed very well…log homes r considered great warm n winter cool n summer…would that b a survivable home and safe w the logs?

    1. Michael Post author

      More mass is better, so a log home would be better than a stick built home. But wood isn’t as dense as one would think.

      For comparison the following thicknesses of material provide one halving thickness: 11 inches of wood, 2.4 inches of concrete, 3.6 inches of dirt.

      Ideally you want at least 10 halving thicknesses of a material for a fallout shelter. So to get to ten halving thicknesses with those materials you’d need 9-foot thick walls of wood, 2-foot thick walls of concrete, and 3-foot thick walls of dirt.

      This also doesn’t take into consideration the roof, which would also need that amount of shielding. It might begin to make sense why fallout shelters are usually underground.

      But why 10 halving thicknesses you may be wondering? That’s really only needed if you are near a blast and subject to the initial radiation of a bomb. Fallout has a half life measured in hours, not years. So fallout decays to safe levels very quickly. So if you’re up in the woods and days away from a blast a log cabin with one or two halving thicknesses in the walls and virtually zero on the roof would provide more shielding than stick-built cabin, especially if it was raining and the fallout on the roof was washed away. But if that log cabin had a small root cellar built into a basement with concrete and/or dirt on all sides, it would provide far better protection. The occupants might need to stay inside for a few days or even sleep there for a few weeks, but the rest of the house should be fine and definitely a better place to live after the bombs stop dropping and the fallout outside continues to decay.

      1. jenn

        Thank u for the feed back I am going to build a shelter within my basement floor a plan for at least 6 people… wish me luck just have to put n air flow to it right?

      2. jenn

        Thank u for the feed back I am going to build a shelter within my basement floor a plan for at least 6 people… wish me luck just have to put n air flow to it right?

  4. jim

    Im helping a friend up north with a underground fallout shelter he wants to bury a house trailer would someone please get back to me and tell me how to do it right.and if it can be done.thanks so much.jd

    1. Michael Post author

      Sorry for the delay, I just spotted your question.

      Just my opinion, but I don’t think there is any good way to bury a travel trailer. I know that folks have done this, but the water-proofing and external forces would be just too great.

      Even a shipping container isn’t designed to take the pressure of earth pressing in on the sides and roof. It’s designed to take weight on it’s 4 corners.

      So I’d think of the shelter more like a big underground garage that you happen to have permanently parked a trailer inside – if you choose to go this route. Then engineer that garage to take the weight/moisture of the earth backfill around it.

  5. William

    Also if you do something like this take into consideration that you can double the sqft without doubling the price. Or just taking an 8×16 and adding an extra 4ft to each of the 8ft walls you can increase the sqft by 50% for very little extra cost. While it might not seem like a lot of room every little bit helps.

    1. Michael Post author

      I agree completely. The small examples I’m showing here are small to show how easy an effective shelter could be.

    2. William

      As a quick example to my above comment. Lets say a 10ft wall takes 100 blocks and a 20ft wall takes 200 blocks. So to make a 10×20 structure it would 600 blocks to get 200sqft of space. That is 2 walls at 200 blocks (400) and 2 walls at 100 blocks (200). If you were to increase the size to 15×20 using the above numbers you would only need 100 more blocks and that would give you 300sqft. That is a 50% increase in space for 1/6 of the blocks it took you to build the entire 10×20 structure.

      One other thing to take into account is that a concrete company will charge extra for half and quarter loads so it is best to build your structure if money permits to use a full load of concrete.

  6. Rick Fowler


    All of you need to look at Armor Screen as a protection for windows in earth shelter or even underground homes.

    As most of you know, one of the inherit weaknesses in building earth shelters is the windows. Unless you can afford bulletproof glass, providing real protection against high winds is a serious problem for earth shelter dwellings.

    With that in mind, consider the following:

    I have been watching the development of Armor Screen since its inception and would seriously consider it as a means of protecting the weakest part of the earth shelter – i.e., windows.

    Please check it out and consider adding it to your lists when designing an earth shelter structure.

    Here’s the link: http://armorscreen.com/

    Rick Fowler

    PS – I found out through those who have installed it on there above ground homes that they now have an “automatic” drop down system allowing the screen to robotically operate thus covering all of the windows before the winds hit the home. Is it possible to “hook up” the system with a storm warning modulator that detects suddenly changes in pressure zones warning of a potential tornado?

    Just some food for thought…

  7. William

    I was wondering what the round about cost was for you to build the size structure you talk about in this article. I’m just curious on the cost of the block and concrete to build the basic structure. I am not worried about the costs to dig the hole or beds or any of that. Just the basic structure costs.


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