How to Build an Underground Bunker

Get Permission

Getting the appropriate permits is crucial as they guarantee safety for both you and those nearby during the project. Disregarding or failing to secure a permit can result in costly consequences and possibly pose risks if caution is not exercised.

It’s important to avoid beginning excavation and construction of an underground shelter, only to later be halted and subjected to a substantial penalty. In certain circumstances, you’ll be required to dismantle or reverse any efforts you’ve made.

In order to acquire the necessary permits, it is essential for you to visit your nearby building department or official. It is imperative that you have your blueprint (more information on that will be provided later) and a map indicating the area of your operation, as you will be required to present them your plans.

The permits required for building a bunker can differ based on your location. If you plan to build one in San Diego, CA, there are specific permits that you must obtain.

Grading Permit: Grading is required when a project may alter the topography of a property due to excavations or fillings. A preliminary evaluation is needed to make sure you aren’t building on environmentally sensitive lands and to assess the feasibility of the project you’re conducting.
Building Permit: This is to ensure the construction project complies with local, state and federal law.
Discretionary Permit: When a project has the possibility of impacting the surrounding area due to the proposed use, location or design feature, a discretionary permit is needed.
Plumbing Permit: If you’re adding plumbing for your underground bunker (more on that later), a plumbing permit is necessary.
Electrical Permit: If you’re going to install any electrical wiring or equipment, you’ll need an electrical permit to make sure everything is wired safely and correctly.

Regardless of your location, ensure you call 811 prior to digging to prevent unintentional damage to underground utility lines, which can pose a risk to your health and result in hefty expenses. Although it may take a few days, a locator will be able to identify the location of any buried utilities.

Choose the Location

After attaining the necessary permits, the next step is to carefully select a secure and private location for your bunker, taking into account the importance of maintaining confidentiality.

It’s best to steer clear of areas in close proximity to large bodies of water due to the increased risk of flooding that can compromise the stability of your underground shelter. Additionally, it’s advisable to avoid any locations that are susceptible to catching fire.

It is advisable to steer clear of excavating in areas encircled by trees and vegetation. If you trench near trees, you will have to cope with intricate root systems that are hard to sever. Additionally, damaging these roots may harm the surrounding environment.

Similarly, it is important to refrain from excavating near utility lines. By contacting 811, you will be informed of the exact location of utilities. Keep a distance of 18-24″ perpendicular to and directly above the utility line. If avoidance is not possible, you may want to reconsider the location of your bunker.

Pick the Right Bunker Building Material

Ensure that the bunker is constructed with a durable material that can withstand the pressure of the surrounding earth. Building below ground level requires different materials compared to traditional construction. Various building materials are available, but not all are suitable for underground structures.

Metal Sheeting – Metal sheeting is sturdy and water-resistant, but can also be expensive, especially since insulation would need to be added.
Bricks – Bricks, are sturdy and relatively affordable building materials that are also great insulators and incredibly weatherproof. They can also add style and color to an otherwise dreary situation.
Concrete – Reinforced concrete can withstand high loads and is relatively cheap. Self-healing concrete is an advanced building material that reduces maintenance requirements and has about a 200-year lifespan.

Avoid using wood as it is highly susceptible to weathering, decay and may attract pests. It is acceptable to employ wood for interior decoration of your shelter, but ensure it remains neat.

Even though shipping container bunkers offer affordability and ample space, there is limited room for customization of the layout. Additionally, reinforcing the containers is essential since they are not originally constructed for burial.

Once your bunker materials are prepared, the subsequent task is to determine the process of excavating the earth.

Acquire Key Living Materials

Simply burying a metal box in the ground won’t suffice; to provide lasting protection for both yourself and your loved ones, an underground bunker must be equipped to meet extended needs. It’s important to include the following five crucial components in your planning:

Ventilation and Air Filters: These filter and ventilate clean air into your bunker. An N.B.C. (Nuclear, Biological, Chemical) filter is your best bet at protecting your shelter from air contaminants and providing fresh air.
Generator: This will provide electricity to your bunker. To determine how much power you will need, add up the total wattage of everything that uses electricity. This will give you an understanding of how to choose the best generator for your bunker. Consider installing a solar generator to avoid needing to stockpile fuel, or keep it around as a backup.
Water Filters: These will keep a reliable source of clean water on hand. Any water filter can work, but for an underground bunker, a UV filter is optimal. They use different frequencies of UV light to rid the water of viruses and bacteria.
Waste Removal System: Mismanaging waste can be detrimental to one’s health. For an underground bunker, there are a few options you can go with:
- You can keep it simple with a room with a trench, like an outhouse. It’s cheap and quick, but it can be unsanitary.
- A “poop tube” is a quick way to deal with waste, and they’re easy to make, needing only some PVC pipe. They’re not great for long-term use, however.
- A composting toilet needs no water; instead, it transforms waste into fertilizer, which is excellent if you have plants, but they can be a little pricey and smelly in enclosed places.
- A wastewater pump and lift system is a popular option for controlling waste. These systems pump waste from lower to higher elevations.

Ensuring an adequate supply of bottled water and non-perishable food is imperative and should not be skimped on as they serve as protection for both your shelter and those residing within it.

Stock up on Provisions

Regardless of whether you face a nuclear meltdown or an end-of-the-world situation, you will need to stay in your bunker for a while at the beginning of the event. To survive, FEMA suggests that you provide each person with enough food and water for at least two weeks.

Always remember to follow the 7:10 rule of thumb for determining the potential radioactive hazard, regardless of the circumstances. The rule posits that for every seven-fold increase in time elapsed after an explosion, there is a corresponding ten-fold increase in the likelihood of a radioactive event occurring.

In essence, the rate of exposure to radiation is 400 roentgens per hour once two hours have elapsed since the explosion. However, after 14 hours, the rate of radioactive exposure is reduced to one-tenth of that value.

Ensure that the food is both nutritious and long-lasting. Some examples of the most nourishing non-perishable foods are:

Dried/canned beans
Dried/canned fruits and veggies
Dried/canned meats
Peanut butter
Nuts/seeds
Grains
Protein bars
Canned soup
Non-dairy and dry milk

It is important to regularly replenish and swap out your food supply to avoid consuming expired items in the event of an emergency.

It is recommended to have a microwave or alternative cooking methods for emergencies, such as canned heat or a portable butane stove. Candles can serve as a reliable source of light and slow cooking by placing a can or pot on a stove and positioning a candle underneath.

Since radiation can rain down for up to 24 hours after detonation, it’s crucial to prioritize water. Additionally, it’s advisable to have an ample supply of vitamins and other supplements.

In the same manner, your subterranean refuge need not be a bleak and dreary space. You ought to make every effort to avert any psychological harm resulting from seclusion. Cabin fever is a commonly used expression used to describe unfavorable emotions arising from isolation. This may lead to:

Restlessness
Irritability
Difficulty concentrating
Lethargy
Depression

Be occupied by hanging pictures or putting in a sound system for music or even setting up a space for exercise to keep yourself engaged. It is imperative that you also prioritize your mental wellness as important as your physical health. Hence, always remember to take care of your mental well-being.

Underground Bunker Plans

#1 Septic Tank Design

A fundamental underground shelter can be installed inexpensively and relatively quickly using a durable concrete septic tank as its foundation.

Approximately one-fifth of homes in the US currently have a septic tank in place, however, that fact is not beneficial in terms of shelter. Even if your septic tank is functioning to detain and purify your bathroom effluent, it cannot be utilized as a living space, but you may choose to build a custom bunker in your backyard instead.

A septic tank with a capacity of 1,500 gallons, which is commonly used, has an approximate size of six feet in width and ten feet in length, providing about 60 square feet of floor area. With a requirement of 10 square feet of space per individual, this size would be adequate to accommodate up to six individuals in a bunker.

You have two options for creating an underground bunker with a concrete septic tank: purchasing a pre-made tank from a reliable vendor or constructing your own.

An average of $1,590 is the cost for a 1500-gallon pre-cast concrete septic tank, which is significantly less expensive than an average underground bunker. For perspective, an 8′ x 12′ small bunker is priced at $45,500!

Although transforming a septic tank into luxury underground accommodation may be difficult, it is possible to make it secure and habitable.

Adding insulation and ventilation to the bunker can be achieved with ease by using polystyrene insulation panels and 12v computer fans. These measures are essential to ensure the safety of the bunker.

To enhance your underground experience in terms of comfort, it is possible to set up a rudimentary plumbing arrangement and lighting.

#2 Root Cellar Bunker Plan

Root cellars are not just suitable for fruits and vegetables to thrive in, as they can also provide shelter for humans for prolonged periods. In our past article about root cellars, we have shared valuable suggestions to aid in planning and have discussed the advantages and disadvantages of different structures.

Useful plans for a root cellar can also be found here.

By utilizing your creativity, it is possible to transform a simple root cellar into a shelter located underground or in the backyard, which can provide a secure haven in the event of an emergency.

#3 Below Ground Corrugated Steel Culvert Shelter

The US Department of Defense designed a steel bomb shelter plan in 1962 that included eight distinct shelters for families without access to community shelters.

This shelter is designed to provide “fallout protection” and withstand radiation after a nuclear attack, as well as being fireproof. Although intended for three individuals, it could potentially house a family of four for a few days.

Learn how to locate the fallout shelter closest to you by reading further.

The design incorporates a pre-made steel culvert similar to those produced by Atlas Survival Shelters. However, the cost has significantly increased from the 1962 price of “$150 or less” and now amounts to approximately 10 times more.

To construct a steel bunker, you can utilize a 48″ culvert pipe, but it must be of top-notch quality to handle the soil weight that you will use to cover it up.

#4 Concrete Underground Shelter

If you want to ensure adequate shielding against radiation, fire, and the impact of explosions, a subterranean bunker made of concrete would be a smart choice. However, the thickness of the walls must be between one to three feet to make the bunker effective, which will considerably raise your expenses.

Ensuring protection against a nuclear attack requires constructing an underground bunker that is approximately 10 feet deep, which is a considerable task.

To tackle a project of such magnitude, it’s advisable to maintain simplicity in your plan.

This presents a simple blueprint for a concrete underground shelter that serves as an excellent model. It is comparable to the readily available pre-made bomb shelters on the internet, but building it should be significantly cheaper than the $80,000 estimated cost.

#5 Wooden Underground Shelter

Even though this video is not recent, it offers valuable tips on how to create a wood underground shelter. To ensure durability and staunchness of the structure, a concrete foundation is essential while the sidings can be reinforced by wooden stud walls.

After being finished, this subterranean shelter can accommodate four individuals, yet it is likely that they would not wish to remain inside for a duration of more than one or two nights.

#6 Brick Underground Shelter

This is another product presented by the Department of Defense, which consists of a combination of bricks and blocks made of structural clay.

If properly constructed, this subterranean shelter, intended to be constructed alongside a new home, has the capacity to house six individuals and remain functional for a maximum of three decades.

#7 Steel Bunker

These step-by-step videos were made for British television and are about the construction of a stainless steel bunker, which is quite unusual.

The material utilized for its sides being stainless steel sheeting and the reinforced support for its roof demonstrate how a survival bunker, considerably safer than an underground shipping container, can be constructed.