New Footing Method

Discussion in 'Framing and Foundation' started by Sparky617, Nov 7, 2017.

  1. Nov 7, 2017 #1

    Sparky617

    Sparky617

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    I was watching This Old House the other day and they were using a new footing that didn't require digging down below the frost line in Mass, where it is typically 48". It is on the video at the link at around 5 minutes.

    https://www.thisoldhouse.com/watch/newton-gennext-all-decked-out

    Around here our footings only need to be 12" for most structures assuming you land on undisturbed earth. If you're on fill it can be a lot deeper. Has anyone seen these in use in real life? Looks like a neat concept.
     
  2. Nov 7, 2017 #2

    nealtw

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    They have been approved in a few states for decks and sheds, haven't seen them out here.
     
  3. Nov 8, 2017 #3

    mudmixer

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    There could be a problem if the uplift from frost is considered.

    The biggest foundation area is the concrete center-piece that will get frost under it while the lower soil could still be damp and provide no resistance for the "spider-legs" that can be raised or bend.

    Having the outer part of a deck heave upward in comparison to a house with proper footings is not very functional.

    The ground freezes from the top down, so the "cute" concept of spreading out the possible vertical support does not affect uplift.

    Dick
     
  4. Nov 8, 2017 #4

    nealtw

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    It seems to be passing that test.
    http://www.startribune.com/a-new-type-of-deck-footing-diamond-piers/211348291/
     
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  5. Nov 8, 2017 #5

    Sparky617

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    Thanks for the link Neal. TOH typically is willing to try out new products, new in this case is 10 years old. They may have just been approved in the town where the current project house is located.

    I understand builders reluctance to try "new and improved" products because they have bitten them in the a-- too many times. Great products like aluminum branch wiring, Masonite siding, polybutylene plumbing, 1980's flame retardant plywood sheathing.
     
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  6. Nov 8, 2017 #6

    Chris

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    I would think those pipes would rsut out over time? I know they are galvanized but that stuff doesn't last forever.
     
  7. Nov 8, 2017 #7

    Sparky617

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    With limited exposure to air, they should last a very long time. Certainly longer than the wood posts installed on top of them.
     
  8. Nov 9, 2017 #8

    Chris

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    But compared to a typical concrete footing, which is made to last longer? It's easy to take care of wood above ground or even replace if necessary, for most it is difficult to replace a footing.
     
  9. Nov 9, 2017 #9

    nealtw

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    How long would you expect the gal. steel to last.
    When was the last time you saw them taking down electrical transfer towers, or chain link fencing.
    The very best treated lumber with a tag that I have ever seen said forty years.
     
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  10. Nov 14, 2017 #10

    billshack

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    i think this might be O K in the usa, but here in canada where the frost goes to six feet or more , one year it went to 8 , i would not try it , also if you are a contractor until this stuff is accepted by the canadian building code you are leaving yourself open to lawsuits.
    Bill
     
  11. Nov 14, 2017 #11

    nealtw

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    Canada is a big place, our depth is 18":trophy:
     
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  12. Nov 14, 2017 #12

    mabloodhound

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    Those are only approved for decks, porch or small outbuildings. Not acceptable for whole house foundations.

    Dave Mason
     
  13. Nov 14, 2017 #13

    mudmixer

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    They are not acceptable for use on a deck that is attached to a permanent structure(home).

    The permanent structure is isolated from frost heaving, but the outer support of th deck cannot allowed to heave upward. - They don't always come back down.

    Dick
     
    Last edited: Nov 14, 2017
  14. Nov 14, 2017 #14

    mabloodhound

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    The Home show referenced did have the porch and roof attached to the house and only the outside footings were replaced.
     
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  15. Nov 14, 2017 #15

    Sparky617

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    This sounds more like regular deck blocks than the product used on This Old House. They used them for the front porch and the posts were supporting the roof over the porch.
     
  16. Nov 14, 2017 #16

    nealtw

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    I would like to see how they work. If you have added pipes to or below the frost level. That will leave the lump of concrete and 90% of the pipe is still exposed. The holding power of that bottom bit is more than frost heave.:)
     

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