Excavating Clay

Discussion in 'Landscape Architecture and Design' started by EDL, Nov 29, 2000.

  1. EDL

    EDL LawnSite Member
    from MA
    Posts: 110

    Today I started a patio job, i knew there would be a lot of clay, we dug down about 9" and hit sand, however there was only about an inch of sand then more clay, so we dug down another 6", What should I do, I figured I would put down landscape fabric then about 6" of 3/4 crushed stone and then hardpack with an inch of sand, Any suggestions Thanks Tom
     
  2. Guido

    Guido LawnSite Silver Member
    Posts: 2,085

    STOP DIGGING!!

    Well I'm on the other side of the world, and my paver consultant in the states counseled me a little bit on the different methods, but here goes.

    First off, clay is not a bad base, its hard, your alright. You should only dig it deep enough for your base coarse and your pavers. Now that you dug down so deep, your going to eventually have some settling, especially if you don't do a Super Duper job compacting your base coarse in lifts. (2-4")


    Now, I'm not sure you need it or not, but landscape fabric is useless for that, in my humble opinion. If anything you want to use geo, but its probobly not a must in your case.

    And for your base coarse, 3/4" stone with sand on top will not compact. REAPEAT: IT WILL NOT COMPACT!! For a good base coarse you want a good mix of large, medium and fine aggregate. If you try to compact an angular rock like you want to, you have too many spaces in between, you need the mediums and the fines to fill in the gaps and give you a quality base. We use 4-6" if it will only have walking traffic and there is a good subgrade. Make sure you spend enough time compacting your base because of the subgrade you disturbed; I can't stress that enough!

    For your finish layer, the way I'm told is washed sand. I know some people use chipstone or fine stonedust but I guess powers much higher than you or me formed an institute and they say the sand is the way to go. I'd take their word on it!

    Well, the morale of the story is, if you have a good base, don't mess with it!! Only dig until you hit stable ground.

    My paver consultant wanted me to include this link to a past thread on this subject. Thanks Lanelle!

    http://www.lawnsite.com/showthread.php?threadid=3053

    [Edited by guido on 11-30-2000 at 04:07 AM]
     
  3. paul

    paul Lawnsite Addict
    Posts: 1,625

    Follow what Guido says :)
    It will save you lots of work!

    Nice touch on that old thread :)
     
  4. Lanelle

    Lanelle LawnSite Bronze Member
    Posts: 1,361

    Yes---do as Guido says and please stop digging.
    If we dug until there was no clay, we'd have to haul away the whole state! Good Luck
     
  5. Stonehenge

    Stonehenge LawnSite Bronze Member
    from Midwest
    Posts: 1,277

    With the exception of the sand, I agree with guido and everyone who is agreeing with him. But if you peruse the old thread guido referenced, you'll read all about that. No need for me to rant about sand.

    But hey, as I read the old thread, I see that EDL started that one, too!
     
  6. Guido

    Guido LawnSite Silver Member
    Posts: 2,085

    We use stonedust or fine chipstone, whatever you want to call it, and I always have, but my "paverchic" says sand is the way to go. I guess thats what ICPI says to use. Thats why I got a little sarcastic around that area! I'm assuming this is what you do right?

     
  7. EDL

    EDL LawnSite Member
    from MA
    Posts: 110

    Thanks for the help, but the clay was very wet and unstable
    Reasons
    1) the house blocks the area of sunlight,
    2) A Hill is on the other side of it
    3) two down spouts, one from the garage, and one from the house empty into the area, plus the drive curls around it and is sloped towards the area,

    We used a lot landscape fabric, crushed stone and hard pack and compacted very well. The base is much stronger now, before you could have jumped on an area and seen the ground move about ten feet in front of you. We also put a nice grade on the patio sending half the water onto the driveway, then down it. The second half exits the other side, down a hill. We also told the homeowner to get pipe extenders for the down spouts.
     
  8. Stonehenge

    Stonehenge LawnSite Bronze Member
    from Midwest
    Posts: 1,277

    Guido - right on. I use limestone screenings - probably the same animal you're using. I don't intend to start another debate here about sand vs. screenings, because I think the thread you referenced covers that issue.
     
  9. Lanelle

    Lanelle LawnSite Bronze Member
    Posts: 1,361

    Does anyone use lime to firm up wet clay?
     
  10. Guido

    Guido LawnSite Silver Member
    Posts: 2,085

    We use Lime for moist soil and we use portland cement for sandy soils. Theres always a debate over lime or portland for moist soils, but all the books I've ever read go with the lime. I'll have to use my reference book to look up the specifics but both worked, and we've used both succesfully.
     

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