How to excavate/fill/build upon this?

Discussion in 'Hardscaping' started by soopa, Apr 15, 2009.

  1. soopa

    soopa LawnSite Member
    from NY
    Posts: 135

    I'm putting together a design/bid for a raised patio to replace this...

    [​IMG]

    We already demo'd the existing structure (everything above grade, and all the slabs on the ground), and ran into a gotcha of sorts. The existing structure was built with CMU, the blocks are buried at least 4 courses below grade around the perimeter of the structure and in the entire area of the steps. Obviously, being 32" below grade, the blocks are holding onto quite a bit of water. All of the fill inside the structure was/is clay.

    Here's a quick layout of what may go in it's place...

    [​IMG]

    The red line is the foot print of what we took out.

    My question is, if I avoid placing my wall footings above the existing perimeter, can I avoid excavating/filling the existing block? If not, what should I do? Excavate just the buried CMU or excavate the entire area to the depth of the cmu/virgin soil? In either case, what should I use as fill? Clean 1.5" minus rock wrapped in textile (as we may do in the case of new construction)? Rip rap?

    The new raised patio will be 30" above grade and likely filled with 1.5" minus w/ fines (crusher run).

    What do you think the chances are the patio fill, wrapped in textile, will be stable enough to span the areas of buried CMU?
     
  2. soopa

    soopa LawnSite Member
    from NY
    Posts: 135

    Also, if I have to overdig the area of the previous structure should I then overdig the entire area of the new structure? I'll pretty quickly eat up this guys budget if so.

    Old patio was roughly 10x16, new will be roughly 13x21.
     
  3. Bru75

    Bru75 LawnSite Senior Member
    Posts: 585

    That's a tricky situation. You might very well have to dig out the whole thing. Might be a good idea to have an engineer check it out, last thing you want is all of your new work to settle.
     
  4. soopa

    soopa LawnSite Member
    from NY
    Posts: 135

    I was kinda thinking the same thing. Unfortunately. Never had to bring an engineer before... any idea of the cost? Guess I'll be hitting the yellow pages.

    Anyone encounter something like this before? What did you do? I'd hate to lose this job, customer is a great guy, but I'd hate even more if it were to fail.
     
  5. soopa

    soopa LawnSite Member
    from NY
    Posts: 135

    Where's all the usual have-all-the-answers guys? Any ideas?
     
  6. ParkviewNursery

    ParkviewNursery LawnSite Member
    Posts: 41

    Are you digging it out by hand or with an mini x? Geo isnt gonna save you here, theres another trick with the geo that i have done, in situations where i had settling problems. But all depends what you have spec'd in here for prices.
     
  7. soopa

    soopa LawnSite Member
    from NY
    Posts: 135

    mini-ex.

    what would your plan of attack be?
     
  8. ParkviewNursery

    ParkviewNursery LawnSite Member
    Posts: 41

    i think you got tooo many stairs there as well on your drawing :p
     
  9. soopa

    soopa LawnSite Member
    from NY
    Posts: 135

    there's probably one too many going up to the door, as 3 steps would put a step level with the door... but otherwise... 7" steps... thats how many i need...
     
  10. ParkviewNursery

    ParkviewNursery LawnSite Member
    Posts: 41

    Take it all out, might as well ....its gonna take 30 more mins? And run your base up. Dont worry on an over dig on this though. If you left it in your run the risk of when packing, busting up some of the CMU and some you wont..... I would however look at having a landing by the door and then maybe a step or two down, i hate the look of just steps to the door, without a landing pad.
     

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