Before you even begin work on your underground bomb shelter you need to understand several important things about the workings of a nuclear explosion. If you are within about 10 miles of a likely target your shelter must be able to withstand the up to 2,000 mph blast wave and the bone-crushing overpressure brought with it. And, regardless of your location, you will need protection from radiation, which will arrive as radioactive fallout. Your shelter must also be sufficiently ventilated and contain certain items crucial for your survival (water, food, etc.) After you satisfy these three important concerns, it’s time to choose the style of underground bomb shelter that fits your needs.
Underground Bomb Shelter Construction Materials
The materials you use in constructing your underground bomb shelter can range from cement block or stone, wood, poured reinforced concrete, and steel. The most important factors are strength and support. The shelter must be strong enough to withstand the pressures exerting around it, while supporting the three feet of soil above it. Understand that soil becomes heavier as it gets soaked from rain and snow.
Obviously, an underground bomb shelter that is too wide while too long would need added support – a lot of added support – and could still become unstable over time. Take a “12 feet wide” by “12 feet long” shelter, for example. Unless you have expensive steel roof trussing, you are definitely going to need additional supports (such as poles or posts) emplaced along the center of the room. But, a wood-framed shelter which is short in girth can be as long as you want it to be. For example, an underground bomb shelter which is 6 feet wide and constructed with tightly placed 6″ x 6″ pressure treated wooden ceiling beams can be 100 feet (or more) in length. And, if constructed correctly it will not need additional interior supports (like poles or posts running along the center).
Wood-Framed Underground Bomb Shelter
The best (and least expensive) configuration calls for a wood-framed underground bomb shelter. One which contains enough room to not make you feel closed in, yet not so wide as to permit a cave in. A wood-framed underground bomb shelter that is about 8 to 10 feet wide, with a support post/pole situated every 4 or 5 feet along its center is arguably one of the best that can be built. The length of this type of shelter can vary. But, constructing one like this will be easy and cost effective. The simplicity of building such an underground bomb shelter is better appreciated as the length of the shelter is extended. The greatest advantage of a wood-framed underground bomb shelter is that just about anyone can build one.
Block-Framed Underground Bomb Shelter
An underground bomb shelter constructed with block offers a solid, strong frame. The costs associated with working with cement and cinder blocks can be higher than the costs of a wood-framed shelter. And, most of us are not brick masons . . . meaning we would have to hire a professional to build our shelter’s frame.