Seeking footing information for deck

Discussion in 'Homesteading Questions' started by whistler, Apr 6, 2006.

  1. whistler

    whistler Well-Known Member

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    I'm building a deck for my cabin and can't find any good information regarding floating pads. I do not want to dig regular below-the-frost-line-footings for this.

    Is there an online resource that somebody knows of that can help me. Specifically I am: looking to calculate the overall size of the floating pads (e.g. sides and thickness), wondering on the necessity of reinforcment (e.g. rebar), and deciding whether I should be putting a thin foam layer under the concrete.

    Thanks in advance.

    Whistler
     
  2. stanb999

    stanb999 Well-Known Member

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    If it attached to your house it must be below the frost line. If not then you can make a standard concrete slab and attach the deck to the slab. But with that much work you might just leave it a patio. It's generally easier to put in the few posts to frost depth and be done with it.
     

  3. whistler

    whistler Well-Known Member

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    Generally I would agree, but digging a hole at the cabin is no fun at all. In digging the holes for the cabin piers we often had to winch out rocks 24-36+" in diameter. Many hundred pounds apiece. In fact several of these footings do not reach below the frostline but instead rest on a rock too big to get out of the ground.

    BTW -- There is no road access to the cabin. Everything comes in by boat or, in the winter when you can't dig anyway, over the ice. Ergo, no heavy equipment.


    Whistler
     
  4. dennisjp

    dennisjp dennisjp

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    If your dirt, or should i say rock is like that, you'll have a good footing for a deck. Scrape away any dirt you can and cut a small trench leading down hill from it. Take a hose and just wash away the soils until you are setting on the rock. Form up a 12"x12"x4-6" high form where each post will set and sense it is hard to get materials in, use quickcrete, but add a shovel of porland cement to each bag. It isn't strong at all by itself. You can use 3 or 4 inch stones that are laying around the house to make it go further but scrub them with a stiff brush in water so the concrete mix will addhere to them really well. I have built several decks like that and the inspectors around here know if I did it, it was done as well as posible. You won't need to worry about the frost line because the bottom of the rocks will be well below that.
     
  5. logbuilder

    logbuilder Well-Known Member

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    Sometimes the right thing to do is not always easy or fun but that doesn't make it any less right.
     
  6. Westwood

    Westwood Well-Known Member

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    Sometimes the right thing to do is not always easy or fun but that doesn't make it any less right.
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  7. kmaproperties

    kmaproperties Well-Known Member

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    Home depot and lowes sell the deck feet, they are made of concrete shaped like a pyramid with a slot for the 2x to fot in. I put a 16x16 barn on them 6 years ago and it is still doing fine.

    Concrete filled holes would be best but these blocks work fine.
     
  8. whistler

    whistler Well-Known Member

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    This is exactly what I am thinking except that I would like a little bigger pad than what is available commercially. Granted, a homemade pad wouldn't have the fancy grooves and such but that might not be all bad.

    Decks of this sort do meet national code requirements. I just can't find what those requirements are.

    Whistler
     
  9. kmaproperties

    kmaproperties Well-Known Member

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    you could make your own pads by nailing forms from 2x8 lumber, you can make them 2ftx2ft and stick a bolt in the center which will accept the post base.

    dig down into the topsoil maybe 6-8 inches then set the form over that. you would have 16 inch thick footer to set the deck on. Unless you have very wet conditions and severe freeze thaw ,they will not heave enough to notice.
     
  10. whistler

    whistler Well-Known Member

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    You do have a point and I would generally agree, however the floating pad method is just as viable as dug footings. It took a little over 100 man hours to dig 15 holes. I can't justify spending 20 man hours to dig three holes for a deck -- not when there exists a viable alternative.

    Whistler
     
  11. wy_white_wolf

    wy_white_wolf Just howling at the moon

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    If it is a deck only (no roof attached to cabin) than there are no national codes. May need to check state and local though.

    If it has a roof attached to the cabin then it does need to meet the same codes as the cabin.
     
  12. whistler

    whistler Well-Known Member

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    I don't know if you are engineer, but what kind of load would a pad that size be able to handle? Should I be using mesh or rebar at all?

    Whistler
     
  13. kmaproperties

    kmaproperties Well-Known Member

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    As long as the deck is not connected to the house, it can be on the floating pads.

    if you bolt one side to the house then and only then do you have to go below frost lines
     
  14. whistler

    whistler Well-Known Member

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    I did not know this. www.deckplans.com, a retailer of the precast blocks, mentions the national building code and so was basing my statement on that. sorry for the confusion.

    whistler
     
  15. kmaproperties

    kmaproperties Well-Known Member

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    Below grade, a proper footer for the center posts in your basement are 36 inches square by 8 inches thick with 2 rebar.
    Spaced every 12 feet this will cary 1/3 the load of a 2 story house.

    The point being that 2x2x16 would carry any deck you could build and put 40 people on it.

    I am a mechanical engineer turned builder 20 years ago.
     
  16. whistler

    whistler Well-Known Member

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    So 2X2X8 should carry a chunck of a deck easily then. Thanks for the info.

    whistler
     
  17. kmaproperties

    kmaproperties Well-Known Member

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    yes 2x2x8 would and 2x2x16 would be a major overkill.
     
  18. wy_white_wolf

    wy_white_wolf Just howling at the moon

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    I downloaded this from that site http://www.deckplans.com/images/pdf/CodeStatement_Bowser2005.pdf Starting at the bottom of page 2 gives a list of criteria that must be met for his statement to be true. It's just that if a deck is built to that criteria than no codes apply so thier decks "meet or exceed" national code requirement. I noticed he didn't reference any specific codes.
     
  19. whistler

    whistler Well-Known Member

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    I made some assumptions that can't be readily backed with any meaningful information. I hate when that happens. Again, sorry for the confusion.

    Whistler
     
  20. Cabin Fever

    Cabin Fever Life NRA Member since 1976 Supporter

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    Sorry. I came into this a little late. I am having trouble with the terminology that you're using. What exactly do you mean by the term "deck?" To me, a deck is something made of wood that you have lawn chairs and a BBQ grill on. Are you calling a a concrete floating slab, that will be used as the floor in your cabin, a deck? If so, I'd simply check with a garage builder on how they construct floors.

    Most cabins that I'm familiar with in Minnesota dig a perimeter trench about 12" wide and 24" deep. The floor within the boundaries of the perimeter trench is 6" thick. Nowadays, they pour the floor over sytrofoam insulating sheets and use a concrete that has fiberglass in it for strength against cracking (I would still use reinforcement wire mesh in the floor). There are 10's of thousands of cabins in Minnesota that are built on floating concrete pads.