metal-shed-protection-from-emp
EMP

A Metal Faraday Cage Garage – Will It Protect From EMP?

I was asked if this would be effective as a ‘Faraday cage garage’. “I have a very big workshop/Garage and it is 95% metal. Would it protect in the event of an EMP attack?”

The question was from way back during 2012, which inspired this original post. I just read through the article comments. Good stuff in there. It’s a good topic. One which we do not have definitive absolute answers to.

I’m re-posting this and will add more to the original content below (I’ve learned more about the topic since back then).

To get you started, you might want to read this article:
Nuclear EMP Components E1, E2, E3, and what they mean…

Faraday Bags for EMP
(view on amzn)

Faraday Cage Garage

Will a metal building protect from EMP?

An enclosed metal structure will certainly provide some amount of protection (attenuation) in the event of an EMP (electromagnetic pulse). However…

There is one potentially very big caveat though… that is, there can be no big ‘leaks’ in the structure. A 95% enclosure will still allow electro-magnetic radiation to get in, provided that the opening(s) is larger than the wavelength of the electromagnetic radiation. More on that in a second…

An ideal Faraday cage would be an enclosed metal ‘box’. ALL (6) sides, including the floor. Conductive mesh screen will work too.

Maybe you have a metal garage or shop building. And you’re wondering if it’s EMP proof. A sort of faraday cage garage. A metal roof. Metal walls.

But… do you have windows? Those are big openings! Is the door made of metal? And, what about the floor? Will an EMP get through the floor? This is all debatable.

Any of these could be the Achilles heel for EMP protection.

Sol-Ark

Electromagnetic radiation from an EMP, if strong enough, will be conducting through the top surfaces of the ground and may find its way in through the ‘open’ floor (in the sense of ‘electrically’ open). A well constructed and grounded floor ‘may’ suffice though – poured concrete with re-bar that is well grounded for example.

The E1 pulse of an EMP will do the most damage to electronics. It happens faster than the blink of an eye. The pulse may rise to its peak value (up to, possibly 50KV per square meter) in about 5 nanoseconds (0.000000005)! To put that in perspective, ‘the blink of an eye’ takes about 300 milliseconds (0.300000000).

Research papers indicate that it’s the very high frequencies (up to around 1 – 2 GHz) that are of most concern regarding electronics damage from EMP.

“The electric field strength of an EMP remains fairly constant in the 10 kHz to 1 MHz band and it decreases by a factor of 100 in the 1 to 100 MHz band and continues to decrease at a faster rate for frequencies greater than 100 MHz”.

Excerpt from QST August 1986, “EMP and the Radio Amateur” and condensed from NCS TIB 85-10

I mention this because it has to do with mesh size (‘holes’, gaps, openings in the structure) as it relates to frequency / wavelength. Obviously a solid metal enclosure is not issue. But it’s good to generally understand what you might ‘get away with’ with regards to openings.

It appears that EMP field strength decreases by at least an order of magnitude for each decade of frequency above 1 MHz.

So with all that said, the frequency wavelength up around 2 GHz is somewhere around 5 inches or thereabouts.

That means a gap that size will allow that frequency right on through. Not good…

However the smaller the gap, the more it will attenuate that frequency. Long story short, without getting into all the math… For EMP protection, it appears any typical conductive screening (e.g. aluminum window screen) should do a good job of attenuating. There’s more to it, but that’s the general concept.

[ Read: Thoughts Regarding Faraday Cage Techniques For An EMP ]

EMP Shield

So, what about that metal Faraday cage garage? If I had a metal building with a metal roof and no windows, setting on concrete with rebar, I would feel pretty good about EMP protection to an extent. Hopefully we never have to find out.

As a side note, I do have a 40 foot metal shipping container on the property. However those things have wood floors. So maybe it will help with EMP (somewhat), or, maybe not.

Better yet, in either case, keep a homemade Faraday cage (galvanized can with lid – with interior lined with non-conductive material) inside the metal building or shipping container (sort of double protection?)…

[ Read: How To Decide What To Keep In A Faraday Cage ]

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74 Comments

  1. If the nearest FM broadcast transmitter cannot be received on the car radio with the doors closed, it is a pretty good bet the structure will provide some protection. The closer and more powerful the transmitter tuned in, and not heard, the better…

    1. Yes, the pulse could be induced along external wiring (street pole wiring, etc.) and enter the building along the wire and zap whatever is connected to the electrical circuits inside. If the wiring is held within metal conduit (which itself is grounded), then the pulse should not escape into the air inside the building, but only fry electrical circuits on its path.

  2. I have a 2 story 4 bay metal garage I am planning on using chicken wire on all the interior wood surfaces as well as the fiberglass doors, the main areas for car and truck have 1/4 diamond plate on the floor areas should this be enough?

    1. The diamond plate will acct as a conductor not the sixth wall of a Faraday cage which must be mesh. The physics involved are not complicated but more then appropriate for this venue. Please look it up for the details. This will provide you enough understanding to perform DIY work. You may want to put the mesh in the floor then thick rubber over it to insulate it from your Diamond plate

  3. I have an all metal garage with hog panels in the concrete floor and metal window screen over the one window ,will this work? or would it be better to build a cage out of 2x4s and cover it with metal window screen inside the garage to protect my vehicle , like a window screen stall.

  4. Will a grounded 20 or 40 ft shipping container also work to prevent EMP damage for items stored inside?
    I also have 2 10 ft diameter stainless steel tanks 20 ft long each for storage fully grounded that I would have the same question about.

    1. Carl – a well-grounded shipping container sounds like a good idea. Ensure that the items inside are well insulated from the metal surfaces.

      1. Yes walls floor and ceiling as well as end panels, doors are 1/2″ plywood covered already

    1. The problem may be the windows – an EMP will still get in through the windows, unless you have metal screens. Additionally, the floor (as well as the ceiling and walls) would have to be all metal (as opposed to a wood floor sitting on metal support beams).

  5. When you say “Screen” I am thinking of aluminum screening used in windows to keep insects out. Will this type of screening protect from EMP? Obviously, one has to be careful not to use plastic screening.

    1. Yes, the metal screening (for windows) will work. The hole size is apparently small enough. However, if part of a structure, the screening will need to be electrically bonded to the rest of the conductive material that is being used to enclose the space.

  6. I have a 40 x 60 metal shop. The side panel do not touch the concrete floor, with is surrounded by treated wood. I also have appox 16″ light panels at the top of the side walls. I would like to use a galvanized wire mesh to bridge roof and side wall panels. What size mesh and does the connections have to be bare metal, it seem to me that at those volts and amps, that the current should make it. Does the walls need to be grounded and is the concrete floor an issue, have no idea of the metal content, thank you

      1. Thank you Blackjack, that is awesome, I think I will double it up for redundancies sake, thanks again

  7. I have a wooden garage. can I jack my car up on wooden blocks and wrap my entire vehicle with metal screen and still be able to use my vehicle afterwards? if not what can I do inside of a wooden structure?

    1. “jonny” Your car might start, but, you won’t be going very far because, the gas station pumps won’t be working to fill your car with gasoline. And, the only thing you might be able to do with a “wooden structure” is burn it for heat because your furnace won’t be working; the lights in your house won’t work either. And, if you have a well for water try using bottled water because, that won’t work either. Even your wrist watch will stop. In other words, we will be going back to “the stone age”; well, almost.

      1. I get that. I live in town and don’t have room to build a metal building on my property. I will be prepared with gas. I already have been taking gas from a can and refilling my cans. I just want to be able to get my family out of this city in the event of an emp. are there older cars that would not need any protection? I wont be burning my garage. lol

        1. @jonny
          Most pre-1980 vehicles will need slight repairs to become running, you will need things such as a new condenser and coil. There are a lot of good references to this on the Blog, and on the net. There are a few vehicles that “should” run after an EMP, you need to do a little research for those tho.
          NRP

          1. Jonny, please get out of Dodge NOW. A running vehicle is going to be a huge target for the powers that be and anyone else. Expect heavily armed road blocks and police confiscation of your vehicle and everything that is in it.
            I have an older diesel pickup that might be able to run after an EMP but I wouldn’t attempt to run it until everything settles down. I also live at my bug in location.

      2. Ugh no, why do we still have analog watches in the military? Your digital watch won’t work. Many analog devices have a good chance of not being affected.

      3. Would it be safe to use a lead box to put your electronics in to prevent the emp strike from being able to kill the electronics that you are looking to save?

    2. Picture this: All roads plugged with dead cars. You will NOT be able to get out. Ditches along roads might be guarded to keep people in. Either way, if you try to walk (and carry your wife or children because they are not suited to walk so far – PLUS any supplies) you will not get far because EVERYONE will rob each other carrying anything of value. Simple things like water, flashlight, good walking shoes, coats, sunglasses, hats, sleeping bags, blankets etc will be very valuable and stolen. The best place is a small town in a very rural area. A solo farm is vulnerable.
      Cooking and keeping warm without someone knowing you’re doing it is impossible. Wow, what’s the future then? Nuclear water, plants and animals will all be radioactive to eat. Your stored food will be fought for. Hopefully you can get home. It’s best to live and work where you want to be.
      If you are concerned move rural now. However Artificial Intelligence will eventually monitor us ‘wherever we are’. Prayer and a relationship with God is the best weapon. Being willing to die for a righteous cause is honorable in God’s eyes and weighed against the devil towards his downfall.

      1. This is where you need a bicycle. The Chinese rode bicycles for decades. That is a good way to get rid of fat. Most Americans are too too fat. We Americans are the fattest people in the world. Check it out on the internet.

  8. Pretty much anything older than 1970. Beyond that point depends on the make and model. I think they started putting electronic components in the cars in the early 1970’s.

  9. I have been seeing a lot about the double sided aluminum radiant barriers products that have small perforations in it. Would this product work when making a Faraday cage?

  10. I’m building a 10×8 metal shed. I laid footings and the floor will be elevated about 5 in off the ground with a wooden plywood base. Will the screws in the floor create a problem?

  11. @ Justin

    If you are planning the shed for a Faraday Cage you MUST line the floor with steel sealed to the walls and roof. NO gaps anywhere even the door

    NRP

    1. Does it matter the thinkNess? And can I use aluminum foil for the gaps or should I rivet a metal flap over the door seem

      1. @ Anonymous

        Nopers, thickness makes little difference as long as ya have 0 (or very very very small) gaps.

        NRP

        1. In radio engineering and testing a Faraday cage is an essential. The door seals are made using brass or copper “finger stock”. That’s a length of flexible material with one side cut into conductive fingers. It’s attached to the door frame, also metal, and makes good contact with the metal door when the door is shut.

  12. I live in a 1975 mobile home that is aluminum sided and has a metal roof. I’m concerned primarily about cell phone and smart meter frequencies as my entire mobile home community has smart meters and there isn’t much distance between houses. I’m getting mine removed but would like to know what kind of protection I might be getting from my aluminum siding from RF pollution.There seem to be a number of answers both in support of this idea and against, & the purpose seems to be making a tight faraday cage rather than reducing the kind of RF I’m referring to. Not sure I understand about the screening on Windows needing to be attached to the primary conducting material- does this mean for screens on Windows to block RF/EMF/magnetic/electrical radiation it might be connected to the aluminum siding? Also I had (husband has it now) a 1981 Dodge Ram van, one of the reasons I wanted it was I thought vehicles pre-’83 were pretty EMP resistant. i also want to get a good meter to use for testing my appliances and home for leakage/fields/pollution but my mind seems to melt a little when reading all the specs . Different kind of radiation, frequencies, measurements, devices… And I don’t have $$ to waste. Thorough but affordable testing is needed & maybe an “electrical and magnetic energy for dummies” manual lol Thanks

    1. i have a spare iphone, laptop, inverter,cb, world band radio etc to wrap in H.D. alfoil and put in a metal lined garbage bin and leave them there. phone towers and power /solar as well will go out but may be fixed in a few months i figure. i have a backup hard drive with music, videos, wills,photos. I have a 2kva gen ill keep in a metal container in a air-cell lined shed. i feel i’m getting paranoid but the threat at present is very real 16/10/16. all this besides the cheese and crackers.. I have a small bar frig i’m thinking of making a sarking cover for (all sides and lined) might work and preserve some foods.

  13. An old Mercedes or Volvo diesel with a generator and electro mechanical regulator would be the cats pajamas. The Russians were slow to adopt solid state electronics during the cold war. They had tube type equipment for quite a while. I assume it was because it also was tolerant of emp. I have badgered friends in the military and government regarding how we can protect against EMP but they have all been very tight lipped about such things. Apparently they still think its some sort of state secret. Nope cat’s out of the bag.

  14. I have a tin shed with air cell completely surrounding it bar for the roller door and a window/ i will put form-board with metal facing over the window. the rolled door is the problem. should i get some sheets of iron with air-cell attached to get a better seal. I’m guessing i need to keep airtight and make a filter for radiation fall out and the dust particles 3 days after last explosion. I’m about 180 km from a major city. by the time i get it sorted the war will be over and a hand growing from my shoulder.

  15. just bought a Generac 22k emergency unit , setting on a prefab slab . any suggestions for enclosure? T Y

    1. Dick cubbeley
      Be sure that you have it set up for easy to reach the oil filter, and oil exchange, spark plugs. Read on reviews that those areas can be difficult for repairs if not set at angle for easy access.
      Depends on where you are setting this unit at in relationship to the home.

      We built a small room for our old generator placing out of the weather. It was designed so that I could access the areas for what I mentioned above. The doors were set catty corner from the unit, we also had a window so that heat would not build up in the room. At the time we did this it was our only power source. The noise level was reduced when the seller put an additional muffler(small car muffler) on it, Kohler Brigs & Straton engine 5kw.

  16. I have purchased a yeti portable solar generator with 2 sets of portable panels. What should I do to protect these items?

    1. Chris, I advise to search the blog for “EMP”. There are lots of articles, some offer potential solutions. Lots of great comments buried here too.

      In short, protection will require a Faraday cage. (search that term here too)

      Basically visualize a metal mesh or metal box (all sides, top & bottom). Electronic devices inside (isolated from touching the metal walls) will be protected to an extent – depending on other factors.

      Some suggest a metal trashcan and solid fitting metal lid.

      The sky’s the limit as to design, size, attenuation factors, form factor, etc..

      There are additional factors of the EMP itself which will affect what theoretically happens too.

      (that’s my short answer)

    1. Elvin

      Personally I would not depend on simple Mylar Bags to protect from an EMP, remembering you also need to isolate the items inside from the covering.

      The company advertised on this site “Crossbreed” has a line of such ‘bags’ that are designed to do what your asking.

      I have a simple metal 55 gallon drum set up as a Faraday Cage for EMP Protection, I have lined the inside with 1/2 inch of Corrugated Cardboard, the steel lid is removable; so I seal the lid with metal tape after adding or removing ‘stuff’.

  17. If such a senerio ever played out, the world would be changed forever. Would it even be worth trying to survive something like that?

    1. @Samuel Johnston, That’s what will make one of the differences… the will to survive under difficult conditions. Some people (many people?) just give up when confronted with challenge.

  18. My plan is to take a 20 foot shipping container. Weld a solid metal floor sealed welded. I buried it half way in the ground. Just pull in and close the doors tightly. Additional note. A rubber bladder is a good idea on the inside. Pool liners seem to work well. Double line the floor.

      1. Joe c;
        You mean Lavaman
        Aka Tommyboy
        Aka Nailbanger
        Aka Nailbender
        Aka Kalufarmer
        Not to worry, he’s just going through a slight Identity crisis 😎

        1. NRP
          ROFL
          Yes
          So.many name changes. I have no clue.
          ……. except for the sarcasm. Lol
          He’s still.my uncle….. whatever

      2. Tommyboy please go back to Nailbanger. Tommyboy evokes an image of that Obama Care Pajama Boy drinking hot chocolate and saying “lets talk about healthcare”.

        And Sir That not you dude.

        1. Oops my bad
          Chris Farley……Tommy Boy
          I was thinking.of some other actor..
          Will Farrell or whatever I believe
          And.no.
          you ain’t no Tommyboy

  19. “Rods from God” are not a new concept. They are an example of a Kinetic Energy Weapon (KEW) and work strictly on the basis of kinetic energy. The formula for kinetic energy is E = 1/2 mv^2. That is, the energy imparted is equal to one half of the value of the mass times its velocity squared. If you use something heavy and get it going very, very fast, you get a lot of energy released upon impact. Another example of a KEW is a railgun. The “Rods from God” proposal uses a long (up to 20 feet) slender (6-12 inches) titanium (for weight, strength, heat resistance) rods mounted on steerable satellites in medium earth orbit with small simple rockets motors. Once the satellite is maneuvered to the appropriate launch/aiming point, any number of rods can be released with a rotational spin for stability and accelerated toward the earth. Gravity takes over from there to continue the acceleration through the atmosphere to the ground target. Terminal velocity would be hypersonic, somewhere over 30,000 fps. A 20-foot titanium rod 1 foot in diameter weighs a little over 2 tons. Impacting at 36,000 fps, that would release about the same energy as a 1KT nuke upon impact, but with no radiation. That’s about 100 times bigger than MOAB (.01 KT). There is no EMP associated with the “Rods from God”, although some KEW launchers, like railguns, use electromagnetic pulses to launch their payloads. Those pulses can cause small localized EMP-like disturbances.

    “Rods from God” does not (yet) exist. We know that because it’s real hard to hide a satellite from either radar or telescopes. However, a lot of research has been done on KEW, and surface-based KEW weapons do exist.

  20. NEWS…. Iran launched their FIRST ever military satellite into a 200+ orbit yesterday. They claim it was successful…I pray it truly was NOT successful!!!!! 😧

    1. NEWS… Iran just launched their FIRST ever military satellite in a 200+ orbit yesterday!!!! they said it was a success…I hope and pray it was NOT a success but a duddd!!! You all best clamber to get to your daddy !!!! Your Creator GOD JESUS CHRIST. Yeshua for you Israeli’s …instead of goofin around with your cars!!!!…He just may save your buttocks here and now if you plead forgiveness for leavin Him outta your LIFE!!! Plus disobedience and surely He will save you afterhere!!!!

  21. the Rods From God are a Kinetic energy weapon traveling at such a high rate of speed between launch and gravity that when they hit the ground they possess more energy than most conventional weapons. All from the mass+speed = energy (not the exact equation) with zero eletronics or explosives, just mass and speed

  22. Was thinking of using 40′ cargo containers. Burying bottom half, with ramp type access to doors. These have. Double doors, opening from middle. I saw note about the roof. What would be good to help protect that area? And, would I need some way to seal door hinge and where they come together? If so. Suggestions?

    1. CaptainT:
      A Shipping Container is a fairly nice choice, Bury at your own risk, making sure to rust proof it.They do have a tendency to collapse when buried.
      The doors can be EMP resistant by using a secondary hinged metal strap or screen to overlay the “cracks” making sure to seal it well against the steel walls of the container.

      1. Thanks. Thought about the spray on like Rino Shield. Like truck beds. What about the top?

  23. I am about to use 3 8′ ground rods attached to 3 corners of my metal shop. The floor is concrete. I understood that the ground rods would compensate for the concrete floors as, electricity (in every wavelength) seeks the path of least resistance. Was I incorrect in my understanding?

    1. Brian,
      It certainly couldn’t hurt, so to speak. If you have the rods, you might as well install them. At worst, it won’t make a difference. At best, it will. Sounds like a reasonable precaution for what you’re trying to do.

  24. When we moved, I purchased a refurbished 20’ shipping container for storage of our water totes and larger preps.Was thinking attaching a ground strap and copper rod to one of the bottom corners. Anybody try this?

    1. California (Adam):
      No need to, the container is fully wraped in steel, the only leak for an EMP is the door seals

    2. Cali-Adam,
      Agree with NRP (sigh..again). You could do the ground rod/ strap thing, but the metal container is in contact with the ground anyway right?. The container is sealed and that makes for the Faraday cage effect. BTW any power cords or pipes going through the walls are a path for EMP frequencies to follow into your container.

      1. Minerjim:
        Dude, people are going to start talking….. LOL
        Up is Down
        Right is Left
        Front is Back
        Inside is Out
        40 Shipping Container is a heck of a Faraday Cage for sure.
        Plus it don’t need to be grounded, supposedly the “bad stuff” will travel around the surface.
        BUT all speculation. Although I’ve been inside a Cupola when it got hit by Lightning…. OMG talk about LOUD!!!
        But it did work, and saved my azz.

  25. The cage should be grounded to a cold water pipe if it is inside. Outside drive 5′ copper rod into the ground and ground your shed to that.

  26. The cage should be grounded to a cold water pipe if it is inside. Outside drive 5′ copper rod into the ground and ground your shed to that.

  27. 21 Bravo, Old Alaskan,
    Same comment at the exact same time? You two twin brothers from different mothets?

    1. No… Somehow “Old Alaskan” was in the name box, but I didn’t notice it until I hit “enter”.
      Since it was my post I originally, I corrected it by re-posting the comment under the correct name.