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Boulder walls

Discussion in 'Landscape Architecture and Design' started by Green Grass, Apr 1, 2006.

  1. Green Grass

    Green Grass LawnSite Member
    from MN
    Messages: 163

    Hey i do lawn care and irrigation for a living. But i have to build a bolder wall next to my house i was wondering if there are any secrets that i should know.
  2. Jamesgateslandscaping

    Jamesgateslandscaping LawnSite Senior Member
    Messages: 421

    What size boulders? We did one last year, 2-4ft diameter rocks, they were huge and offset them so that they would interlock w/ each other, came out very nicely. Here are a couple pics.

  3. Jamesgateslandscaping

    Jamesgateslandscaping LawnSite Senior Member
    Messages: 421

    And another....

  4. randallwise

    randallwise LawnSite Member
    Messages: 46

    I would say it depends on the height of the wall. Can't go over 4' as you probably know. Anything over 4' and you'll have to have it engineered.
  5. Dirty Water

    Dirty Water LawnSite Fanatic
    Messages: 6,794

    If you have to go over 4', find out how far back walls have to be set back from each other in your area's code, and build two 4' walls on a terrace.
  6. olderthandirt

    olderthandirt LawnSite Platinum Member
    from here
    Messages: 4,899

    Each rock was between 4 & 5 ft. set the top course back in 12" from the bottom when there this size. They wont move
  7. JimLewis

    JimLewis LawnSite Fanatic
    Messages: 6,872

    Well, it depends on what size of boulders you are referring to. There's a big difference between building a wall like the ones in the pictures above (using very large boulders that are moved around with a large track-hoe) and a wall using 1 or 2 man boulders that you can lift and move on your own.

    See my website below. Check the pictures section. We have a section there just for dry-stack rock walls using the 1 and 2 man smaller boulders.

    Anyway, some basics; First, you'll want to prepare the ground properly where the wall is going to be placed. Excavate below grade several inches. And excavate back a foot or so from the back of the wall. This is because you'll be backfilling with gravel, for drainage reasons. Anyway, then you install and compact several inches of gravel as your base. Then you start to lay your first course of boulders. This first course should be partially buried - below grade. This stabilizes the wall. Then you start to stack and backfill. Stack and backfill. It's like trying to fit together a puzzle only the pieces are from different puzzles. So you just keep trying and trying different boulders until you find two that fit well together. After a while it becomes easier.

    Do the first course first. Backfill that course as you go along. Then start the next course, and backfill again as you go along. The backfill holds the boulders into place so they don't fall backwards.

    Also, study about the concept of batter. You want your wall to pitch back a little bit as it goes up. That keeps the rocks from falling forward.

    You'll want to have a wide variety of boulders at your disposal as you build the wall. So get more than you need. You can always return or save what you don't need. But the more options you have and the more pieces you try in each area the nicer the wall will turn out.

    That's about it.
  8. treedoc1

    treedoc1 LawnSite Senior Member
    Messages: 319

    I just stacked these with the dozer so I didn't have to keep cutting back from the house I'm building. Not much movement with these...most are at 6-8' tall. Not as pretty as the ones purchased from the quarry, but I was just trying to get the house done and use up what was on site....function first. Work from one end and go back across the face. Good batter angle is important.

  9. GreenMonster

    GreenMonster LawnSite Silver Member
    from NH
    Messages: 2,702

    I didn't know boulder walls had to be engineered if they were over 4'.

    How do you engineer a boulder wall when each boulder is unique?
  10. sheshovel

    sheshovel LawnSite Fanatic
    Messages: 5,112

    treedoc I call that RipRap

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