Building my own bunker soon and need help

Discussion in 'General Homesteading & Building' started by punkwaffen, Feb 27, 2010.

  1. punkwaffen

    punkwaffen New Member

    I am lucky enough to be able to build a house on my future mother in laws land. I have not convinced my fiancee of this yet, but I want to build an underground house for us. I told her I would build a house above it later if she wanted, but we will see. Anyways, I am looking for personal stories,tips,experiences,etc from you guys. I have looked online alot but there isnt anything satisfying enough that I have found yet so I want more personal info.

    The things I am basically hung up on are;

    -Ventilation. I want to have two systems available. One manual/passive type and one mechanical/electric. I know alot about electronics and such so I have a system planned for the fans and such so that all of them are independently controlled with the ability to blow in both directions. Nothing fancy. Ducting/pipes,the fans, some switches all on a board with labels. That way I can adapt to any future issues like being smoked out or something. This also brings up another issue. Concealing air intakes and outlets.

    I am thinking PVC pipe will do right for ventilation needs. I think I could put the pieces right into the concrete walls before it dries and then just work with it when its all dry cutting and gluing to make it work right. I was thinking 10 inch wide.

    For fans, I was thinking about some of these linked below:
    With a blower to pull air in and push air out at the end of the run if needed:
    Vortex Inline Fan -

    -Plumbing/sewage. I was gonna try to build so that I used the hills/slope of the land to my advantage cause of gravity and all of that. I have NEVER dealt with sewage and wanted some input on gravity or low energy systems that are simple and durable.

    For water, I was going to bury a tank uphill and/or use the many small streams nearby via filtration.

    -General construction. My plan is to find a spot. Either flat or sloped land. If flat I will;
    Dig. Keep all passages and rooms narrow with alot of untouched earth for more support. Leave one foot spacing outside of where I plan the walls to be. Lay down one foot or so of stones of random sizes. Ideally, all small pebbles. Lay concrete slab for floor. Start building walls with wood for supprt and concrete as the finished material. The roof is a bit tricky, as are the ventilation specifications. Ideally I would want to run the vents far away from the bunker itself and hide them, but I do not know how to go about that effectively and most importantly, on a budget. So build roof, fill the one foot gap around bunker with ideally pebble stone and then cover with dirt.

    If the chosen area is sloped;
    I will dig a "step" of sorts into the hill and basically build several linked concrete boxes and cover them with dirt. Ventilation will be a tab easier as I can just make vents in the walls facing away from the hill high up out of reach. Same basic plan. Dig, pebble the bottom, pour slab, erect walls and roof, cover top with dirt and back wall outside with pebbles.

    I will use the french drain method as I think it is called. Long ditches filled with rocks and PVC pipe with holes and rocks inside to drain water away from the bunker.

    For the walls, I plan to use concrete, scrap steel I can find or buy cheap, and a strange idea I have. They sell this stuff that is metal pieces to put in the concrete to help reinforce it better. I am basically going to shred all of my spare electronics and wire to do the same thing on a budget. I dont know how effective it would be, but I have alot of crap to shred so it is worth a shot. Finally a use for my dozens of computer cases, hell yeah!

    I plan to cover the outside faces of the wall with roofing tar and then tarps for extra water and moisture protection of the concrete.

    -Electricity. I plan to roll with solar and generators. I basically want to build a separate connected room for the generator(s) and fuel storage. This room or one close will also probably house the ventilation system parts and the water/sewage pumps if needed. I also want to have power from the normal grid for use until I need the generators. As in; use the power until it isnt there anymore because of whatever reason. Maybe an old military diesel engine fashioned to create my power and maybe run it on biodiesel! That would be pretty awesome and worth the work/smell! I hear those deuce and a half engines can run on anything. Maybe one could be turned into a generator? I am not sure.

    -Heat. I was thinking a wood stove for a very backup method. Like when I am out of fuel. I think the earth, body heat, and the generator(s) will heat the place nicely.

    -Security. Guns and gun ports inside only for choke points and exterior door areas. I just purchased a Cypher industrial grade remote keyless door entry system. Essentially two boxes. One with the 8 button keypad and the other with the brains of it. You can choose ac or dc and what voltage it all runs on. Also some other spiffy extras. It is straight up sexy and will go awesome with a steel door of the DIY persuasion.

    This shelter is going to be a several year project not all at once. I need help from you guys to start planning so I can get materials and start building when the weather is better. Cheap/DIY is what I am going for here. While it is not a good idea to do things cheap when it comes to this, I am not an idiot and have alot of experience in some of the areas involved, just not all. I am pretty resourceful and can make something of nothing. So I would rather buy the parts for something than go for the commercially made equivalent. Also, MILITARY SURPLUS stuff is always a good recommendation to me!!!!

    Thanks in advance guys and gals. I look forward to getting some useful advice and will SURELY post pictures and keep you updated when stuff starts happening. Once I pick a spot to build and get advice on the ventilation and stuff I will be creating a 3D virtual model of the bunker before I start building. So that will be awesome!
  2. GroovyMike

    GroovyMike Well-Known Member

    At the very leat since you are alredy planning before you build I'd plan in a basement "safe room" / "storm shelter" / aka fall out shelter with apporpriate plumbing and ventilation....

  3. allen_idaho

    allen_idaho Well-Known Member

    If you want to conceal your inlets and outlets, you could build an artificial mound over it. Something similar to the image below. This would allow you to hide the vents from view from most directions while still allowing you access for maintenance or upgrades.


    Given the gravity feed system you are looking at, you should be able to build a simple ram pump to provide water to your bunker. That way, you wouldn't even need to worry about using electricity.

    Now sewage is a bit different. You have to be extremely careful there. A hydrogen sulfide leak in your bunker will probably kill you and anybody else in there.

    You should be able to use a simple septic system. And place a ball valve inside the bunker in order to isolate the sewage line if necessary.
    So, for example, if your toilet breaks you just need to flush the line, shut the valve, and repair or replace the toilet.

    I don't think you will have any problems as long as the surrounding soil will absorb sewage water, and that your septic tank is strong enough to be buried at a level deeper than your bunker.

    For reinforcing concrete, I don't think using shredded computer parts is a good idea. It just will not have the same structural integrity as using rebar. And that is not a good thing when you plan on putting copious amounts of dirt on top of your structure.

    Rebar only costs around $1.50 per 3-foot piece. The cost can really add up but for this particular project, I would advise not skimping. The scrap steel would probably work just as well though. But no computer parts.

    For waterproofing, the roofing tar should probably work well enough. The tarps will not work though. It would just be a waste of money. If you are going to spend money on anything, just get some waterproofing membrane. The tarps are too porous and will not last underground.

    The electricity plan seems like a good idea. But keep in mind that a diesel generator is very loud and produces a lot of carbon monoxide. In an enclosed space, that noise is going to be amplified.

    So what you are going to need is some sort of soundproofing for your generator room and a vent hose for your generator exhaust pipe. Safety first.

    Same with the wood stove. You don't have to worry about noise, but keep in mind that the smoke has to go somewhere.
  4. bunkerbob

    bunkerbob Supporting Member

    Thanks UncleJoe for the recommendation. Been there, still doing it. I don't have all the answers but most. By the way use 4" galv. pipe for the first few feet of the vent, then switch to ABS, much more durable and cost effective. I have large 4" steel blade valves to shut off the vents from the exterior. I'm going to use a boat pump up toilet for the sewage that will pump into my existing septic system. Don't use electronic keypads, they would be vulnerable to EMP and would fail at the most inopportune time when you need it most.
    I'm presently excavating a power room under my existing 12kw genset that will connect to the existing shelter. This will house the inverter and batteries for the shelter. My present off-grid solar system will supply the necessary DC current to charge the batteries. I will also be able to remotely turn the genset on and off from in the shelter.
    As you can see from my posted photos I have both electrical powered and hand powered air pumps. Make sure when designing the vent system you put in a particle trap below the intake surface vent, to catch not only debris but any attempt by someone pouring liquid down.
    Last edited: Jun 19, 2010
  5. bstickler92

    bstickler92 Well-Known Member

  6. broken1

    broken1 Member


    You won't live long enough to see your concrete crumble from the rebar corrosion and some roman buildings are only still standing because their walls were almost 3' thick. You need metal to reinforce concrete or you're wasting your money.
  7. JeepHammer

    JeepHammer Well-Known Member

    That's pretty funny!

    There is a highway overpass built about 12 years ago falling apart from rust on the rebar right down the road.

    The bridge over the local river is being fixed right now, it's about 20 years old, and was closed because of the rebar rusting cracking the concrete supports.

    I poured between 6" and 8" thick, used the fiber reinforced concrete with no rebar about 4 years sooner than the bridge was built, and I have yet to have a crack...

    I know EVENTUALLY it will crack, but it hasn't yet...

    I'm a FIRM believer in the fiber reinforced concrete, especially for stressed pieces, like roofs, and it works VERY WELL for me.

    You do what ever you want, I'm not selling this as a home game,
    It's just what the engineering collage recommended as an alternative to having issues with rebar rust/cracking and it's working for me!
  8. bunkerbob

    bunkerbob Supporting Member

    Re-bar reinforced concrete is fine for all but a few exceptions, Bridge Re-bar Corrosion
    Steel-reinforced Concrete Bridge
    I don't believe a thick underground slabs with re-bar will corrode like the bridges or roads that are exposed to the corrosive chloride salt factor, whether man or nature made.
    Using additional fiber and fly-ash would enhance the concrete tremendously though.
    Look at the Maginot in northern France, still viable, still a tourist attraction with inside tours.
    These present day companies recommend the use of steel reinforced concrete lids...

    Complete Underground Bomb/Fallout Shelter Kit -

    Earth Sheltered Homes design and built by Underground Home builder, Davis Caves Illnois
  9. longtime

    longtime Well-Known Member

    I was an engineer (happily retired). I will guarantee you that if you place a 10'X10'X10' piece of reinforced concrete next to a same size non-reinforce piece, the non-reinforced piece will still be around in 1000 years and the reinforced piece will be a unrecognizable pile. However, unless all you plan on doing is making a cube of concrete you need the re-bar, concrete has no tensile strength. You would have to design your structures to always be in compression, like a lot of the ancient structures. The alkaline nature of concrete will keep the re-bar from rusting in you life time.


    Not wanting to start an argument, but here goes.

    Fiber reinforced concrete is not meant to replace structural steel. It is true that if you use steel fibers it will reduce the amount of steel you need, but fibers are to improve impact and abrasion resistance and freeze thaw performance as well as reduce initial curing cracks not tensile strength. If your college said to skip the re-bar in a structural member without design calculations they are wrong. If they did design calculations, I'll keep quite ( but still cross my fingers for you).
  10. Diego2112

    Diego2112 Well-Known Member

    While I was in Czech Republic, we toured some WWII era bunkers. All steel reinforced concrete. Still standing, and virtually indistructable.

    Worked for them, and they are STILL standing (some after taking HEAVY fire), and still VIABLE shelters!

    Just my 2 cents.
  11. questor

    questor Well-Known Member

  12. The_Blob

    The_Blob performing monkey

    old elevator cables make for good 'free' rebar

    our driveway is "6 1/2 sack" concrete 4"~6" thick (thicker on one end than the other) with discarded 5/8" elevator 'rope' (cable), it is almost 50 years old without any cracks & has had heavy trucks (garbage, septic, county snowplow)on it, & IMHO Ohio has some of the most screwed up structure-damaging weather & acidic soil there is ... he also put in a 6" retaining wall done the same way & being mostly buried has shown no evidence of damage

    you can't get most scrappers to even take the stuff, even for free, because it has to be cut into 12" lengths to go through the metal shredder withought causing damage & most companies are not going to pay an elevator service team $200/hr (calculated wages & benefits) to stand their with torches and cut that crap up

    as for "lasting 1000 years" :hmmm: :dunno: but then again, you won't have provisions for that length of time :sssh: so it's fairly academic...

    if you want permanency, buy land with a CAVE into bedrock & excavate that into a BOL...
  13. VUnder

    VUnder Well-Known Member

    That bridge may be in trouble, but it would not have even lasted until they finished building it without any steel in it. Plus, the hammering of traffic, water soaking in and freezint, salt, all those factors are tough to deal with. I was building an underground and came across a footing for the old governors' mansion. Footing was 3' x 3' and had rebar. The rebar was not even rusty. Still looked like new. We had to dig the part of footing out that was in our path. The old house was built some time around 1900, as it had already been gone a long time. Luckily we found somebody old enough to remember what was there. If you build underground, you can't keep concrete in compression, so you have to put rebar to give it some tensile for lateral loads.
  14. alcornry123

    alcornry123 New Member

    for sewage look into rv systems for a macerator there is a model that has a 12' lift its what im looking at for my designs go to was just reading an article about ventilation systems and experiments done by the navy they had lots of problems with body heat and humidity 20 people for 20 days go see
  15. Caribou

    Caribou Time Traveler

    I was thinking of something similar. My plan was to build a full basement with a cistern built into part of the foundation. Rain catchment is my preferred water supply but that will not work everywhere. Don't forget to insulate, with closed cell foam, under the slab and around the walls. The ground is an unlimited heat sink and raising the room temperature much above ground temperature could be a real battle.

    If you build your house above the bunker the vents can be run into the attic or through the roof like any other vent.

    If you put PEX tubing in the floor you could salvage heat from the cooling system of the generator.
  16. BillS

    BillS Well-Known Member

    I still think a bunker is a death trap. Even if the entrances are strong enough, you still have the problem of having enough air. I don't see how you could light a fire in one without suffocating. Somebody could block up your air vents and you'd be toast. Worse yet, they could pour gasoline down them and then light it.

    I've seen Doomsday Prepper shows with bunkers and almost all of them are way too small and are dependent on generators when they have very little fuel to run them.

    I think you're a lot better off building a house that looks normal but has reinforced doors and bulletproof glass.
  17. Domeguy

    Domeguy Building the World Round

    Still here . .

    Hi all . .
    i'm still around and can design/build monolithic domes. there isn't another structure that can beat this design for strength, durability, energy savings, safety, and cost effectiveness . . bury it, berm it, leave it above ground. it can stand up to almost anything mother nature can throw at it. (everything, except for a flood), and small arm fire and shrapnel. And, the technology is now avaiable to make it EMP proof too . . .

    Just sayin . . it doesn't have to be difficult . . .!! cutaway.jpg
  18. swjohnsey

    swjohnsey ExCommunicated

    How do you form up the top?
  19. Cabowabo

    Cabowabo Shooter

    Another plus side to doing the normal house but making it into a bunker is that most people will just assume that its a regular old house. That their is nothing worth taking in it.

    When I've mentally built my dream house, its been bullet resistant up to a point, looks normal, and has bullet resistant windows. I'm hopeful that it will be fire-resistant, bullet-resistant, theif-resistant. But like all things if the fire is hot enough, or their is a big enough bullet, or the thief wants in bad enough it isn't inpentrable.

    Also keep in mind if your stuck underground, they can just starve you out. And you can't return fire, or shoot at people trying to take your stuff.