Your thoughts on a underground hide

Discussion in 'General Survival and Preparedness' started by xls, Feb 26, 2014.

  1. xls

    xls Monkey

    Ok I have several things I have built with great success, this however I am unsure.

    The size in question is 8'x8x8'
    in size.
    I plan to place 2"x4" at every joint and spacing them on 16" centers.
    The catch is I plan to coat inside and out, along every edge with the black tar uses in waterproofing a basement.
    After all sheets are covered I plan to do all the bracing.
    Once every spot of wood is covered I will then screw the structure together and the coat the seams again in hopes of preventing or slowing water between the planks and the plywood .
    Once it's assembled I plan to set it off into a hole with a foot of 3/4" gravel,create a 3'x3' opening from the top for access, cut planks to stiffen the opening then simply join a hinged plywood door.
    Once in the hole it will rest just under the surface. At a depth that the door is almost flat , yet above the level of rain run of the ground, then I will bury the unit as intended , packing a bit as I go.

    Now I ask, will it leak? I fear it could . It will be along the edge of woods as well.

    Changes? Ideas? Comments? Thanks guys/ gals
  2. VisuTrac

    VisuTrac Ваша мать носит военные ботинки Site Supporter+++

    I'd say create a grave marker as well.
    do you know how much a half a yard of gravel weights? let alone nearly 2.5 cu. yards.
    I'm betting that if it holds up that much weight (doubtful)
    that as soon as you step foot on the roof, it's going to collapse, you are going to drop in and the walls will collapse in on you. Thus the reasoning for the grave marker.

    If you are going underground, go strong. 2x4's and plywood aren't going to cut it.
    get a shipping container and bury it or go poured wall or block.
    you are going to need to reinforce the roof way more than you think if it's going to be totally underground.
  3. xls

    xls Monkey

    No,no the depth under ground will just be 1.5" deep. The foot of gravel is under it to help water move off the wood itself. Sorry my fault.

    Also I agree if underground a foot depth of soil would likely way 80 pounds a square foot.

    Not my intentions to be underground just the door being flush with it.
  4. ghrit

    ghrit Bad company Administrator Founding Member

    Slope the top. Wood will sag and puddle. Make sure the soil under your below floor gravel will drain. Even if only 1-1/2" of cover, 2X4 on 16" c-c will not make it. Someone will run over it with lawn mower (tho' with only 1-1/2 inches of soil, it'll be bare) and you can imagine what that will do. Design for at least 200# per square foot roof load.
    chelloveck likes this.
  5. cdnboy66

    cdnboy66 Monkey++

    Check a framing table for weight loads for structural members. I.e. Floor joists, then double it
    If someone walks over it and it bounces, they're going to investigate
    I agree with the marker theory as that will give you and anyone that you need to know, a reference point
    The bitulithic coating for parging may not help you, it may cause the wood to rot faster.
    Not sure if you can still get creosote, but even that has a lifespan before wood rots
    I would go with steel stud and double wall with polystyrene insulation externally if I couldn't do block walls

    Concrete is forever
  6. xls

    xls Monkey

    Got it . I wanted to try something different and wasn't sure , now I am thanks guys.
  7. chelloveck

    chelloveck Diabolus Causidicus

    why not research FEMA underground fallout shelter designs for materials point in reinventing the wheel. They will have design features to deal with drainage, weight and stress loadings etc.
  8. Snake_Doctor

    Snake_Doctor Call me Snake...

    IMHO why not just use cinder blocks and insulate with blue board. Or buy a bear den? They are expandable and drop in the hole. The manufacturer suggests encasing it in concrete so you know it's strong. And it's waterproof.
    Yard Dart and VisuTrac like this.
  9. ozarkgoatman

    ozarkgoatman Resident goat herder

    Last edited: Feb 26, 2014
    chelloveck likes this.
  10. kellory

    kellory An unemployed Jester, is nobody's fool. Banned

    Then there is also that inflatable concrete bunker ( complete with locking end doors.) Just add water, and pump it up. Should be able to bury it after it sets up hard.
    Inflate it in the ready dug hole.
  11. KAS

    KAS Monkey+++

    shipping containers need to be reinforced also ...
    The load are ment to be put on the corniers ...
    And they also need to be tarred !!! and laid in some sort of gravel
    VisuTrac likes this.
  12. VisuTrac

    VisuTrac Ваша мать носит военные ботинки Site Supporter+++

    I agree. I saw a root cellar made from a small container. Walls and roof were caving in due to the weight of the soil. They had to dig it out after a while.

    Another note, make sure it's well above the water table.
  13. Dunerunner

    Dunerunner Brewery Monkey Moderator

    Under Ground... I gave this some consideration a few years ago. I thought, I'll light it with oil lamps, No; CO2 and soot. Then I thought, DC.. three or four car batteries! No way to charge them or vent them. Ooo! Vents! I'll need a fresh air vent for air!

    That is when I realized a bunch of burning paper and wood or a tear gas grenade in my fresh air vent would flush me out.

    Gave it up completely and just bought more ammunition!!
  14. Gator 45/70

    Gator 45/70 Monkey+++

    Underground is a no-go for me, I hit water at 3 feet.
    VisuTrac likes this.
  15. kellory

    kellory An unemployed Jester, is nobody's fool. Banned

    um, er....I thought Gators liked water.....
  16. Gator 45/70

    Gator 45/70 Monkey+++

    Only when it's warm. The rest of the time we like laying up in lounge chair's by someone's pool.
    ditch witch likes this.
  17. Tevin

    Tevin Monkey+++

    Why are you trying to reinvent the wheel? It would be easier and cheaper (and safer) to get a prefabricated bury-able fiberglas storm shelter and adapt it for your purpose.

    Also, look into using a length of galvanized drain pipe, or a length of preformed cement drain pipe, both of which are designed to be buried.

    Burying shipping containers is do-able, but there are a lot of caveats that make it difficult.

    Do not make a plywood box and pile literally tons of dirt and gravel on top of it unless you are a professional engineer and have done the proper math. You're not building a tree house. This is not something you can guess at.
  18. Airtime

    Airtime Monkey+++

    Shipping containers can't even handle being buried.
    Look at the walls caving in and supports to keep the roof up in the pictures here:

    2x4s on 16 in centers is not even close. I have read about wood foundation techniques and those were like 2x8 and 2x10s on 1.5 inch centers (ie stacked together). You might research that a bit.

    On the topic of tar coatings. It is very old school and has been around for decades and it is crap for waterproofing. The tar usually continues to outgas and gets bridle, cracks and then leaks at the cracks. Lots of 10 year old houses whose dry basement now leaks when it rains. It isn't bad for sealing concrete to keep moisture from permeating through the concrete but won't bridge cracks when dried. For good water proofing several things are needed: 1. Very good perimeter drainage on both sides of the wall's footer, 2. Drain paths down wall sides to the footer drainage 3. Plastic (usually HDPE) membrane, rubber membrane or rubber coatings that will stretch to bridge cracks. A couple products I have used and liked are Platon and Blue Seal but there are others I've considered but haven't use called Bluemax and Blue Skin.

    I really like Platon and it's not real hard to install.

    If going underground, several things to consider:
    - always have at least 2 exits and a brute force egress method or two such as a sledge hammer and a spot where concrete is thinner and not rebarred.
    - consider making the structure circular. The inward force on the walls will put them in compression which most building methods and materials handle rather well, especially concrete. Large flat surfaces don't like heavy loads - why you see arched and domed ceilings in old large rooms and buildings.
    - you need multiple air vents to extend (usually buried) far away from structure with descret openings and means to force air circulation (pump) and ways to valve any one off and ideally to filter incoming air as well.

    Be careful.
    chelloveck, VisuTrac, kellory and 2 others like this.
  19. Dont

    Dont Just another old gray Jarhead Monkey

    There was a thread in the archives here on this subject... When have time will look it up and put a thing or two in resources on this subject..
    ozarkgoatman likes this.
  20. Snake_Doctor

    Snake_Doctor Call me Snake...

    I'd like to see one of those Kellory
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