We often think of underground bunkers as being the ultimate survival backup plan. Whether it’s a natural disaster, civil unrest, or the zombie apocalypse, these survival shelters can prove to be pretty useful when it comes time to batten down the hatches.
However, if they are not built properly, these bunkers can quickly throw a wrench into your survival plans. Along with stocking your bunker with everything it needs, you need to ensure the structural soundness of your shelter. Read on to take a look at three of the most common weaknesses in underground bunkers and storm shelters.
Underground Bunkers | Important Things to Consider
Entrances are typically the weakest part of a structure. Debris from a major disaster could force the door inwards, in which case you are no longer protected from the elements and are exposed to broken remnants flying inside. You also need to be able to conceal yourself from unwanted visitors.
Your best option is to have a solid-core door, such as a mix of steel and plywood, which you can find here. A steel frame is also an integral part of your entrance. You may have the world’s best storm shelter door, but a weak frame will make it useless.
You may also install a 90-degree barrier outside the door to inhibit intruders from knocking the down the door. Construct a concrete or cinder block barrier with just enough room to open the door and climb inside the shelter.
Check out if your door is FEMA approved.
No Air Circulation
Air circulation is critical. I once heard of a group of folks that hid in an underground school bus. Although this is an innovative idea, the bunker did not have adequate air circulation and the group of people baked to death.
While the ground around the walls offers protection from natural disasters and most explosions, it can also be an oven, trapping heat. You not only need proper air circulation to cycle in oxygen and maintain body temperature but also to cycle out contaminants or contagions.
A simple remedy can occur with two holes and a fan, although HEPA filters can remove airborne bacteria and viruses. You can also use UV light to disinfect the air before it is circulated. Read more about air circulation at The Omega Man.
The amount of time you plan on retreating into your bunker will vary depending on the situation, but you can never count on an exact estimate of time. That being said, sewage and garbage must be dealt with, to avoid harboring contagions and diseases within the underground shelter. Depending on the terrain, a septic tank or sewage system can do the trick. You may also incinerate garbage inside the shelter, as long as there is proper air circulation.
Check out this storm shelter from Lifesaver Storm Shelters of North Alabama:
Building an underground bunker is not as easy as digging a hole for people to hide. A survival situation can last for days, which means you need to make sure people won’t suffocate or live with their own waste. Careful planning is a must before the building process takes place.
Unsafe Underground Bunker Construction Examples
Since shipping containers are made of steel, they are one of the better options for someone who is unable to provide an adequate safety structure for their family. Having said that, there are many reasons why a shipping container should not be considered your best option.
First and foremost, the steel used for shipping containers is thin and weak in comparison to the steel that are used for most bunkers. Once buried, the thin steel will become evident quickly as the roof will likely bow or collapse. Quality bunkers use a special rubberized coating on the outside of steel bunkers, this coating protects against environmental contaminants and corrosion.
Shipping containers have no such coating; therefore, you will find rust, corrosion, mold, and other factors that will risk your safety. Finally, cutting away pieces of the shipping container to allow for access, venting, and customizations further weakens the flimsy structure.
While a combination of steel and concrete can provide unmatched safety, concrete alone cannot withstand the conditions required of an underground shelter. One of the most important requirements for an underground shelter is the ability to expand and contract with the earth’s movement and temperature.
Concrete is rigid by nature; therefore, it cracks when under pressure. Although a concrete shelter may not immediately collapse because of a few cracks, you will likely find moisture related problems, such as mold, within a moderately short period of time. Due to the brittle nature of concrete, the life-span of the shelter will be much shorter than a steel structure.
For some time, there has been an off-shoot of independent thinkers who believe that a round structure is more structurally sound than a square structure. When examining the two types of bunkers, one finds that round bunkers lack the reinforced frame necessary to bear the weight of the structure. In a square bunker, each cross section reinforces the next, distributing the weight evenly and alleviating pressure points.
Round bunkers have no weight bearing joints; therefore, they are highly susceptible to collapse once put under immense pressure. Additionally, square bunkers allow more space for the necessities and custom upgrades without compromising space or safety.
From an engineering standpoint, culverts are designed for water to flow through. They are not designed to be water-tight, not to seal out toxins from the environment. Likely, each culvert will have tiny cracks that will widen and leak over time compromising your living environment and safety.
Non-Durable Underground FIBERGLASS Bunker
Fiberglass, although great for cars and boats, lacks the structural integrity to keep you safe during a life threatening event. For starters, fiberglass products are protected with a gel coating. When placed in a moist, underground environment, this coating begins to crack, giving way to moisture, mold, and pollutants. Furthermore, fiberglass cannot contract and expand with the earth’s movement, as steel can, leading to premature failure.
Other than safety, there are other factors to consider. Fiberglass structures do not allow for custom designs or modifications without costly custom molds. If a customer changed his or her mind mid-project, new molds would need cast, delaying the project and adding thousands of dollars in costs. Furthermore, the structure itself does not contain an interior. It is merely a fiberglass shell. Interior design features are most often made of wood, which can mold, rot, and catch fire.