How To Build a Concrete Bunker Under Your Bedroom
For a lot of preppers, one material prep that is probably at or near the very top of their wishlist is an actual, honest-to-goodness bunker. But this is one prep that tends to cost a fortune if you have it professionally installed.
And though preppers typically have a strong DIY bent, this is an intimidating project, one that most will not be willing to undertake themselves.
And that’s a shame because it is actually entirely possible to install or even build an underground bunker yourself if you have some basic construction skills, a good plan and pay attention to what you’re doing.
Although a true bunker is always an expensive and time-consuming undertaking, it is a lot more achievable than you might think if you do it yourself.
If you’ve been dreaming of the day when you can own and outfit your own underground bunker, take heart because it might be closer than you think. This article is a step-by-step outline on how to accomplish it…
A Word of Advice
I’ve embedded below a video here that is a great step-by-step documentary of one man’s endeavor to install a DIY bunker in one of his buildings.
It shows off some seriously good workmanship, and is a great example of maximizing returns while working within limitations.
Read through this article entirely before you get started, then watch the video. Then come back and go through the video and article again, pausing as needed.
I guarantee you’ll catch plenty of little things that will save you tons of time, money, and grief during your own build…
Step 1: Plan Your Work
When building a DIY underground bunker, planning is the most important part of the entire process. A lack of proper planning can lead to costly mistakes, delays, and even deadly accidents.
Firstly, it’s important to plan the location and size of the bunker. Consider whether the bunker will be installed under your home, next to your home, or elsewhere on your property.
You must also address the material of the bunker (wood? concrete? metal?) amount of space you have, the number of people who will be using the bunker, and the equipment and supplies that will be stored inside.
You also need to keep in mind the soil conditions, water table, and groundwater flow, which can affect the stability, safety, and condition of your bunker.
After the bunker’s location and size are determined, you need to create a comprehensive list of materials and equipment needed for the project.
Without an accurate list, you risk delaying the project or even failing to complete it because you may run out of money, materials or both!
Planning is the tedious but critical element to the success and safety of building a DIY underground bunker.
By taking the time to plan each step carefully, you can ensure that your bunker is a safe and secure space for you and your loved ones and also better guarantee that all of the following steps go smoothly.
If you are following along on the video, you’ll see that our preppers have chosen to site their concrete bunker under a building, with the entry concealed in an office or workroom.
Pay attention to the work being done, and you will see that it is all the result of skilled labor and sound calculation during the planning phase.
Step 2: Perform Safety Assessment
Now, gut check time. Even the simplest and shallowest bunker install will entail some danger. The larger, more elaborate and deeper the bunker the greater the danger will be.
People can and have died while attempting to build their own bunkers, so before you start the project, it’s important to assess your safety.
Any number of things can go wrong: you could encounter an underground spring while digging, a gas line or a power line. You could even get hit with a landslide from the soil above your bunker, burying you alive.
You might fall into a pool of concrete and be unable to get out. You might tumble from a ladder, wound yourself with power tools or heavy equipment, get electrocuted, and any number of other ways that people get hurt on jobsites around the world.
Be honest with yourself about your skill level when considering the project. Also consider the local terrain, whether or not you have enough manpower, and if anyone will be nearby to provide help or summon assistance.
There is no shame in determining that the project is unsafe, for any reason, or that you are just not up to the task.
Pullback and start improving other skills, or go back to the planning step and approach it from another angle.
See if you have friends or associates in a MAG that might be able to lend the necessary oversight and skills to the project, if not manpower, to assist you.
Expert guidance from someone you trust is worth a dozen laborers!
Step 3: Check for and Pull Permits
The most un-fun step of all. The sad reality is that it is essential to understand the laws and regulations on all building activity in your area.
One of the most important steps in this process is obtaining the necessary permits before you start digging.
That’s the last thing you want to do if you’re trying to keep your bunker a secret, but do it you must.
The reason why it’s important to pull permits is that every local government has specific rules and regulations about construction projects.
Even for DIY underground bunkers, permits are usually required. Permits are issued to ensure that the building meets safety and environmental standards.
Without proper permits, you run the risk of being fined or even having your project halted. In a worst-case scenario, you might be forced to dig up or fill in your bunker!
It’s also important to check with your local zoning board to ensure that the proposed bunker is allowed where you plan to construct it.
There could be restrictions based on the property’s location, size, or type of underground construction.
The zoning laws could determine the maximum depth you can dig or any number of other associated factors…
Another important aspect to consider when building an underground bunker is how it could impact the surrounding area.
You should be cognizant of the environmental and geological restrictions covering man-made materials near, over, or in protected or watched zones.
It sounds like much ado about nothing, and maybe it is, but you’ll ignore this step to your own detriment.
Step 4: Excavate
Time to break ground! With this step your bunker is officially underway. The excavation process can be time-consuming, labor-intensive, and expensive, and choosing the right method will depend on a number of factors.
Digging by hand is a common method for small bunkers, those without much money, or as part of the process for more intricate bunkers.
If you have access to heavy equipment, such as a backhoe, digging can be done much faster than using hand tools.
Excavating may take place outside on your property or inside a garage or other outbuilding.
Inside these structures, a smaller or mid-sized excavator may also work effectively, but it’s vital to make sure that the basement or garage’s height, length, and width are suitable for the machinery one chooses.
If using heavy equipment to excavate, it’s crucially important to be mindful of underground sewer and water pipelines, cables and more that could be damaged by the passage of these huge machines, to say nothing of the digging itself!
You should always research and locate pipes, wires, and other types of underground infrastructure as part of your planning phase.
Also, keep in mind that a large fraction of the excavated soil must be disposed of elsewhere: some will be used to fill the dig site once the bunker is done, but much of it will be displaced.
If you don’t have a place on your property to scatter it or leave it you’ll need to have it hauled off.
Step 5: Lay Pad / Foundation (if needed)
Depending on the size and style of your bunker it might need a concrete pad or footer, or else a proper foundation put in before the walls and other components can be erected.
Once the site it excavated, leveled and cleared, it’s time to create a stable base for your bunker.
This will require pouring concrete or creating some kind of foundation structure — such as a perimeter of steel beams and posts — that can support the roof and walls.
This is essential if you want your bunker to last for many years without settling or shifting over time.
This is most easily done if you already have some skill with laying foundations for above ground structures, but it’s not too hard to get right with a little practice prior to the day.
Also keep in mind that some bunkers might be self-supporting in the case of certain prefabricated modules; no foundation necessary. More on those in just a minute.
Considering the stresses and forces that underground structures are submitted to, this is not a component you can afford to skimp on or skip: a good foundation is the cornerstone of a safe, stable bunker.
Step 6a: Build Walls
The next step is dependent on whether you are truly building your own bunker, or installing and finishing out a prefabricated module.
If you are building, you’ll need to build or place the wall sections, taking care to install or prep all utilities and other fixtures as needed during this phase.
Our example video is showing cinder block walls, but there are some different ways to do it, all discussed below.
The blocks can be laid on top of each other and “glued” together with mortar. For a more secure and stronger wall, rebar can be built into the blocks.
Precast concrete panels are another option for wall construction. These panels are pre-made in a factory and shipped to the construction site.
They are then connected and secured with mortar or fasteners. Precast panels offer a strong and durable wall while saving time and labor vs. laying blocks.
For an environmentally-friendly and less expensive option, stabilized earth (reinforced soil concrete) eliminates the need for concrete blocks entirely.
Special soil stabilization products are used to bind the soil for added strength and durability.
Steel structures are often used when building industrial and military bunkers, but they’re very heavy and very expensive.
Whatever method you choose, it’s critical to ensure that the walls are strong, secure, and properly placed, as they serve as the foundation and stability for the entire structure, and will have to resist enormous loads against them from the surrounding soil.
Step 6b: Install Bunker Module
If you are installing a pre-fab bunker module, this is also the time to do that according to the manufacturer’s instructions.
Step 7: Build Ceiling (if needed)
With the walls up, it’s time to build or install the roof or ceiling. If you’re using blocks and mortar, you may want to lay a concrete slab on top of the walls for added stability and protection against water seepage.
All parts of a bunker are important, and the roof is no different. It is the roof, more than most other components, which determines if your bunker is going to be a leaky mess or a watertight refuge for you and your family.
Again, take care to make way for all utilities needed in this step: electricity, ventilation, etc.
Step 8: Paint and Seal
Painting and sealing isn’t just an aesthetic choice: if done properly, it can add another layer of protection and durability to your bunker.
Painting the interior with a waterproof sealant helps keep water out, while a coat of corrosion-resistant paint on the exterior is also recommended.
Every possible place where water or insects and other pests might get in must be thoroughly and mercilessly sealed up.
Omitting this step or cutting corners could see your bunker flooded and eaten up with mold, or rendered completely uninhabitable when you can least afford such an unhappy outcome!
Step 9: Fill
The bunker is installed; now it is time to fill in the hole or cover it back up with soil. This isn’t always necessary, as some under-home bunkers might simply be capped with a concrete slab to blend them back in to a garage or basement floor.
In any case, the soil should be filled in evenly on all sides, working your way up, and gently tamped as required to prevent excess settling.
The soil should be packed down firmly to prevent future cave-ins, and take steps to protect against water seepage.
If you are using sand for backfill, it would be prudent to also add a waterproof coating or lay moisture barrier as an added layer of protection.
Step 10: Outfitting
The bunker build is done, but it is not truly ready yet. All necessary systems must be fitted, hooked up, and installed.
This can range from shelving and sleeper units to compost toilets, hand-cranked ventilators and much, much more.
You will also load your emergency supplies during this step, and test all systems to make sure that your bunker is ready for whatever comes your way.
Something to consider is that a few systems, namely ventilation and electrical installs, are best done concurrently with the build itself on an as-needed basis.
Having to dig out a wall to access a critical location is foolish at this venture, so make it a point to rehearse all elements of the build plan several steps ahead to prevent it!
Step 11: Conceal
With the build done, the hole filled, and the bunker outfitted and operational it is in your best interest to now conceal your bunker.
Bunkers attract a lot of attention in the best of times, and during the worst can become a target by the desperate, the criminal and the deranged. That makes you and your family a target during what is already the worst time of your life.
It’s best to keep its location and existence on the down-low, if at all possible. Plants, stones, bushes, and other elements of camouflage can be employed here to help blend in your bunker with its environment.
Indoor-accessible bunkers may have their hatches concealed using rugs, mats, pads and the like. Wall-mounted doors can be concealed behind swing-away shelves, tapestries, pictures and so on.
Once that is done, take a deep breath and give yourself a pat on the back: you’ve earned it!
DIYing Your Own Underground Bunker is Achievable
Building an underground bunker is a complex endeavor, but with the right planning and plenty of persistence, it can be done.
By following these steps closely your family’s safety should be assured when disaster strikes. Make sure that you are prepared for the worst by investing time and effort into planning your own DIY bunker today…
Tom Marlowe practically grew up with a gun in his hand, and has held all kinds of jobs in the gun industry: range safety, sales, instruction and consulting, Tom has the experience to help civilian shooters figure out what will work best for them.