Some very well intentioned advice but unfortunately some of it is just incorrect or based on outdated concepts. I've studied this myself and I think
I can help you somewhat.
Let's start with misconceptions:
1. You need to be deep underground
- For "blast" protection this is true, but in all honesty if you need protection from a near direct hit you simply won't be able to build a shelter
capable of surviving yourself. If you're within the blast radius of a known target you should look into a pre-built shelter.
The bad news is they are very expensive. The good news is they are very, very nice with battery power enough for 6 / 12 / 32 / 64 / 128 people
depending on which unit you can buy. They also have water, waste disposal, radio / tv masts, tamper proof hatches with gas and projectile defense,
tamper proof and biological / radiological proof air supply, etc, etc.
Here they are - the "Radius" fallout shelter
You should take note of just how large the 25 person "condo" shelter is. It's really, really big.
The truth is as long as you are outside the blast radius you simply need fallout protection. This can be accomplished using a variety of improvised
means, most of which consist of putting enough dirt in between you and the radiation. 6 feet of earth is enough for the worst possible radiation load,
this doesn't factor in blast proofing, however. The owner of the Radius shelter co authors the definitive book on nuclear fallout and blast shelters,
you can find information on the book on their website.
Building a direct hit blast shelter or one within a certain blast radius will be difficult as you have overpressure to deal with. The human limit is
around 20 psi - this means you need any air vents, exhausts, etc to be big enough to supply your population but small enough to prevent the
overpressure wave from equalizing in the shelter. This usually means using just enough total ventilation volume and splitting it among several small
pipes rather than one large one. The commercial shelters add a baffling system to prevent this as well as keep possible intruders from suffocating
you, drowning you or smoking you out.
2. You need a lead lined shelter
See end of number 1. In addition, modern nuclear weapons are "different". They create an intense radiological energy on ignition and leave behind a
type of fall out which disperses faster. While the traditional precautions will still be a good idea the worst of it will be manageable with safe
habits after 2-3 weeks to 30 days or so, (depending on distance from ground zero). There is a radius within ground zero which will be uninhabitable
due to penetration.
3. You need concrete and lots of it
This depends on how deep underground you go. There is a type of underground construction which is cheaper than you might think. I bought the book
"The 50 dollar and up underground house book"
The author has a variety of plans which make
use of his own devised and long tested methods. They make for very inexpensive and fast construction which solves the typical humidity issues. He's
designing permanent houses for living which include an area in them to serve as a bomb shelter. The techniques could be easily adapted to build a
cheaper and more livable shelter.
I actually plan to buy a huge parcel of land in the country and build a residence using these techniques as well as others. His designs usually
include underground greenhouses, a huge bonus in a post nuclear home.
Now that all said, the deeper "underground" you go as opposed to alternatives involving building into a natural or artificial hillside bring the
problem of soil pressure. If you notice, most govt and commercial shelters are built extremely strong, not just for direct hit survival but so they
can withstand the enormous pressure of the soil around them.
You have a variety of options.
You could build partially above ground by creating an artificial "hill" of rocks and soil, even concrete and support beams, etc. Your main concern
would be having enough space for your plans. If you decide to go "deep" you're going to need some consultants to avoid collapsing your neighbors
property or damaging the foundation of your own house.
My first recommendation would be to buy a radius shelter with installation if you can afford it.
The next would be to look into "hacking" your own radius shelter by using a pre-built structure of some sort you can adapt. Following the design and
concept of a radius shelter would serve you well, as would looking into some of the modern architects who design extremely small living spaces.
actually has links to a number of these, a google search for architect+small+houses or
efficient+living+spaces should help you design a living space for 30 people using as small of a shelter as possible.
Another good reference is a civil defense site with plans and data on building shelters, it was updated in 2005 last I can see:
(Those key chain Geiger counters are pretty nice, though you can build your own if you have electronics ability).
Good luck, if you go forward be sure to update us with pics and details. If I manage to build mine before TSHTF I'll do the same.
[edit on 13-10-2008 by nfotech]
[edit on 13-10-2008 by nfotech]