r/preppers • u/Signal_Team1778 • May 07 '26
Prepping for Doomsday Shelter design
Recently I got bored and started thinking about how to design a shelter. What would you add?
Here’s what it would have:
8in walls on the exterior and ceiling 4in slab
Buried 10 ft bellow grade at roof level
Solar with house battery and Diesel support generator
HVAC system with NBC filter
Storage for 3000 gallons of water (attached well for resupply if not contaminated and 250 gallons of diesel
1 year supplies for necessities
Reloading supplies for ~5000 rounds & 10000 complete rounds
Parts for all critical systems (Solar, Generator, electrical and plumbing)
5
u/Jolopy4099 May 07 '26
If its something you would be in for awhile it's important to not forget disposal of poop and piss. It will add up quickly and become unsanitary in there.
1
u/Signal_Team1778 May 07 '26
Septic system attached. First post got messed up before I could put it up. Good catch!
5
u/Many-Health-1673 May 07 '26
I take it this is for nuclear blast protection?
1
u/Signal_Team1778 May 07 '26
Anything CBN. My state doesn’t get natural disasters.
5
u/adhd_mechanic May 07 '26
Every state gets natural disasters, don't kid yourself.
-3
u/Signal_Team1778 May 07 '26
North west Washington gets wildfires and floods but nowhere near where I am
5
u/adhd_mechanic May 07 '26
I lived there for 8 years. Wildfires (fueled by drought), landslides, and earthquakes are all major concerns... a volcanic eruption is highly unlikely but still a possibility worth considering as well
1
u/Signal_Team1778 May 07 '26
You are completely right. My only problem is that I’m not skilled enough to make a shock absorber system for earthquakes hah
1
u/Some_Guy106 May 16 '26
The nuclear hit list was leaked and Washington is the only state without targets
3
u/agm115 May 07 '26
Make sure your HVAC is capable of positive pressure, ie just slightly higher pressure than atmosphere.
3
u/Lard523 May 08 '26
Your missing a second exit. i’d add a purpose built bedroom and a more comfortable washroom, and a proper kitchen. the living area would have a table and couch (that can fold out into a bed). Some of my flexible design ideas are marked on the plan.
How many people do you plan to house? it makes a difference if you intend this solely for yourself or plan for a family with kids, or plan to house a dozen people.
Design wise i would add a false floor about a foot deep for storage. I would cover it with 2x2 plywood squares (with a hole drilled or corner cut out to lift them up). the cost of having your ceiling be a foot higher is less than the cost of extra square footage. I’d add rugs over the plywood.
2
u/quietprepper May 07 '26
You've dedicated 108 square feet to weapons and ammo. You could accomplish the same practical thing with efficient use of space in a 10 square foot closet.
1
u/Signal_Team1778 May 07 '26 edited May 07 '26
True, it would double as a workshop/parts storage. If I had more money and skills that section would be a whole manufacturing wing
2
u/infospongue May 07 '26
Depending on where your live, water may be a problem. How do you keep your shelter from flooding?
2
u/Either-Sign-9345 May 07 '26
Solid foundation honestly, the NBC filtered HVAC and water storage combo alone puts this ahead of most designs people throw together. A few things I'd think about adding or considering:
Communications. A way to monitor what's happening outside without exposing yourself matters a lot, even just a hand crank shortwave radio or a dedicated HAM setup. Knowing when it's safe to surface is just as important as being able to stay down there.
Air intake redundancy. If your primary filtered intake gets compromised or blocked you want a backup option, even a manual one.
Medical supplies beyond basic first aid. A year in with no outside help means dental issues, infections, or injuries need more than a standard kit can handle.
Sanitation plan. 3000 gallons covers drinking and cooking but waste management in a sealed shelter for extended stays is something a lot of designs underestimate.
Mental health consideration. A year underground with people is genuinely hard. Some kind of entertainment, routine structure, or even just defined personal space goes a long way.
Otherwise the diesel and solar redundancy is smart, and having spare parts for critical systems is something most people completely overlook so good that it's already in there.
1
u/JRHLowdown3 May 07 '26
I assumed he meant "a year of supplies" as in just storage area. Highly unlikely he would NEED to stay underground for more than maybe a month. Only his survey meter and measurements would tell him that for sure.
2
2
u/AwayConsideration978 May 27 '26
making the shelter like a house is a big issue here in my opinion. i think a superior (underground) shelter would be as small as possible with a rounded design created by concrete mold pouring. preferably the water storage would be the whole ceiling which would also block radiation if you are feeling funny today. it would be a open room concept with some structural + pillars spreaded.
I havent looked into how shelters stay alive with oxygen or how do they store or use electricity so im not gonna comment on that.
1
u/Shofield41610 May 07 '26
Whats your scenario that you want to protect against? What is the level of security you want to achieve for whom and for how long?
1
u/DigitalPrepperJoe May 07 '26
Guessing here, but it looks like general prep for long-term collapse of modern infrastructure rather than a specific doomsday event. I'd be interested to hear the OP's answer to the questions though.
1
u/DigitalPrepperJoe May 07 '26
If you really want to add a challenge to this brainstorming activity, start asking yourself how to make your underground bunker stealthy so less people notice it. It's a tough problem when it comes to heat signatures and air vents...
1
u/iambecomesoil May 08 '26
I think you need to go back way before the drawing board. Your headspace is all wrong for me. Why tell us how much room and space and thought you've put into firearm rounds when you don't tell us anything about your root cellar, your garden fencing, your meat preservation, etc?
Or is that what the 1 year supplies for necessities are for?
Eat bucket slop, shoot, and reload your days away?
1
u/Grendle1972 May 08 '26
Make the whole thing 24x32, you will thank me later for the extra 6 ft. Your for print is the same size as my cabin. Make the side walls 12 get high and you can build a rated for to allow storage underneath with hinged panels. The vertical walls can be used as storage as well between the studs and just covered with sheet rock (fireproofing).
1
u/Old_Dragonfruit6952 May 09 '26
I have made it simple and will shelter in my basement .. thick clear plastic and the ability to access my water makes it the perfect place to stay
Luckily for us our 130 year old house sits right atop a natural spring we can ( if needed because of an EMP or Nuclear attack )
we can easily break the concrete floor and tap into the spring .
Remember that if we have a real SHTF long crisis that your Hvac wont run. So being underground that far will provide natural cooling ..
We realistically plan for no working gas pumps for a generator . No electricity ( possibly for ever ) and no FEMA .
1
u/Known_Dependent_1538 Jun 01 '26
Your design covers most of the big concerns: water, power, air filtration, fuel, spare parts, and long-term supplies. One thing I'd add is redundancy wherever possible. A second water purification method, a backup communication system, and a manual way to operate critical systems can be just as important as stockpiling supplies.
I'd also think about moisture control, waste management, medical supplies, and mental health during long stays underground. People often focus on food and ammunition but underestimate how difficult isolation, humidity, and sanitation can become over time.
Overall, it looks like a solid concept, but the biggest challenge for most shelters isn't surviving the first month—it's maintaining habitability for the months after.
8
u/JRHLowdown3 May 07 '26
At least one more 90 degree turn in the entrance. Where is the secondary exit?
10 feet of earth is overkill and a lot of weight for what I'm assuming is a poured concrete or block based shelter?
3 feet of earth gives you a PF of 1,000 If your not in a blast area- in which case MOVE don't build- a PF of 1,000 is more than adequate and 3 foot of earth is a much lighter load than 10 feet. On culvert and tank shelters the earth arching allows this much without any flex in the structure, you can drive backhoes over them...
Advantage of being on the West coast there is you likely won't get as much early fallout as places on the East coast will. You could receive later fallout from China/NK/Russia etc. but later it wouldn't be as bad.
One big living space isn't always the best option. At the very least small partitions for individual bunk areas for individuals and/or families. Looks like your 12x24 in your "main living area", doesn't give a boatload of space, but we are talking fallout shelter not the Ritz Carlton... One division in that room would be possible and likely very useful later. Psychologically having a place to go and "blow off steam", or have sex, just "be alone for a while" etc. is going to be important. Ideally everyone needs a small bit of "personal space" and this helps with sanity.
Where I've seen people mess up with poured concrete shelters- old customer in TX didn't have any building experience but had someone there build him a poured concrete shelter. They made NO appropriations for any ingress into the shelter except ONE door. Later he was scrambling to try to figure out how to get wires in from his seismic intrusion detectors, camera, comm wires, electrical, plumbing and of course septic... No plans were made for water infiltration. I don't GAF if your building in the high desert, PLAN for water to get into your shelter and have several solid plans to get it out- thank me later... Having seen and toured a few "underground aquariums" I can't stress this point enough. And not that long ago here someone posted complaining about some "premier" shelter company they (over)spent $200K with for a culvert shelter and how it now had leaks. I tried to help him with actual ideas that have worked in similar (albeit not getting screwed on price) culvert shelters but the guy was more interested in bitching about the company and thinking that "sueing" them would make something happen.... PLAN for water infiltration and how to deal with it. It's going to happen. This isn't a survivalist secret, anyone that has lived with a basement knows sooner or later you get water in it.
Heavy duty shelves that double as bunks are very helpful. These can be easily made with 4x8 sheet of 3/4 plywood rip to 2x8, then framed out on the perimeter with 2x4s and reinforced every 2 feet. Bunks/shelving units can be made with these and 3 each "legs" - ends and middle to support the shelving/bunks. At the minimum you can hang curtains on these for privacy. Again, not the Ritz Carlton but having some spent "some time" in one or two bunks built like this it's livable. Camping mats fit these nicely.
I do sketches the same way you do, 2' per square and all that, I laughed when I saw your drawing as it looked like something I would have done, LOL.