1. Welcome to the new and improved Building Code Forum. We appreciate you being here and hope that you are getting the information that you need concerning all codes of the building trades. This is a free forum to the public due to the generosity of the Sawhorses, Corporate Supporters and Supporters who have upgraded their accounts. If you would like to have improved access to the forum please upgrade to Sawhorse by clicking here: Upgrades
    Dismiss Notice

Foundation on Barrier Islands

Discussion in 'Residential Foundation Codes' started by jar546, Feb 4, 2020.

  1. jar546

    jar546 *****istrator

    Joined:
    Oct 16, 2009
    Messages:
    7,514
    Likes Received:
    642
    I just thought I would share something that is a-typical of SFR construction in most parts of the country. In Florida, when you build near the intracoastal or on a beach that has a dune and you build on the dune, this is typical for a foundation slab. Auger cast piles go down anywhere from 40'-80' and are capped with grade beams as shown with the slab being poured over the top, although in many instances, this is a monolithic pour. The slab, however, is always above the FIRM BFE and of course the FBC DFE which is 1' of freeboard since they are almost always certainly in the special flood hazard area, including my town which is 100% either VE or AE zone.
    Comments?
    Screen Shot 2019-11-19 at 16.33.08.png
     
  2. TheCommish

    TheCommish Sawhorse

    Joined:
    Sep 27, 2011
    Messages:
    929
    Likes Received:
    159
    if wave action undermines the slab and grad beams is it still supporting?
     
  3. jar546

    jar546 *****istrator

    Joined:
    Oct 16, 2009
    Messages:
    7,514
    Likes Received:
    642
    The slab is designed to be self supporting. It is above DFE so it does not have to be frangible.
     
  4. jar546

    jar546 *****istrator

    Joined:
    Oct 16, 2009
    Messages:
    7,514
    Likes Received:
    642
    Here is what a SFR looks like pre-mono-pour.
    IMG_6958.JPG IMG_6959.JPG
     
  5. TheCommish

    TheCommish Sawhorse

    Joined:
    Sep 27, 2011
    Messages:
    929
    Likes Received:
    159
    that is some serious steel
     
  6. Paul Sweet

    Paul Sweet Sawhorse

    Joined:
    Oct 17, 2009
    Messages:
    1,202
    Likes Received:
    195
    "if wave action undermines the slab and grad beams is it still supporting?"

    That's what the piles are for.
     
    jar546 likes this.
  7. ADAguy

    ADAguy Registered User

    Joined:
    Sep 11, 2013
    Messages:
    4,236
    Likes Received:
    405
    So, why would anyone want to build, or be allowed to build in areas knowing that "eventually" it will be washed away? Can these be insured?
     
  8. Ty J.

    Ty J. Sawhorse

    Joined:
    Aug 2, 2017
    Messages:
    909
    Likes Received:
    339
    The view for one thing....

    [​IMG]
     
  9. ADAguy

    ADAguy Registered User

    Joined:
    Sep 11, 2013
    Messages:
    4,236
    Likes Received:
    405
    Is it worth the potential loss?
     
  10. Ty J.

    Ty J. Sawhorse

    Joined:
    Aug 2, 2017
    Messages:
    909
    Likes Received:
    339
    To you, sounds like a no.

    To the thousands of people that live on barrier islands and shore lines, yes.
     
  11. ADAguy

    ADAguy Registered User

    Joined:
    Sep 11, 2013
    Messages:
    4,236
    Likes Received:
    405
    Until the tide rises or the winds blow. Same can be said for why do we live in the mountains, view and fresh air. You make your choices and take your chances.
     

Share This Page