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Boulder formula driving me crazy help?

Discussion in 'Landscape Architecture and Design' started by allpro2009, Jul 22, 2008.

  1. allpro2009

    allpro2009 LawnSite Member
    Messages: 20

    Hey guys, ive just recently been given the chance to install boulders as a border around several beds at 2 of the properties that i service. one is commercial, the other residential. i actually sold them on boulders, rather than retaining block, blk diam, or anything else because we agreed it looked best. My problem is, these nurserys and rock yards are not even coming close to giving me a way to figure these jobs out. Since im new to boulders, i dont know how many i will need, less ofcourse measuring EVERY single boulder, which im here hoping thats not the only answer. it doesnt have to be a perfect formula, but man i cant even get a guess out of these guys. im looking to use volleyball to basketball size boulders, round and not like colors. now from what i can tell these are what the boulder industy considers 1ft (volleyball) to 2 ft basketball) boulders? Please has anyone had experience with this, and can u help me. say i need 80 linear feet worth of edging = _____2ft boulders. since they only sell by the ton, i cant just add the 2foot boulder X my linear feet right? URGGHH IM LOST
  2. White Gardens

    White Gardens LawnSite Fanatic
    Messages: 6,776

    Around here, the local suppliers have a catagory of size. Unfortunatly they aren't all the same.

    One range is 1.5 feet to 3 feet. So, I find the average and do my calculations with that. Unfortunatly you don't know how many boulders are in a ton, as each load will be different.

    So, if you got more than one job to use boulders on, start with the smallest one so you can get an idea on have many pounds = linear feet. If you have any left over, no sweat, you'll just use the excess for the next job, and you'll have a better idea of how much to get.

    It's ok to have some left over in the end, just call it inventory and try to sell them on another job, or just stick a few in your own yard.

    Another thing I've done in the past is on a few small jobs, I'll actually go hand-pick each boulder to make sure I have some uniformity and not have a bunch of small rocks left over.

    Good luck.
  3. JohnnyRoyale

    JohnnyRoyale LawnSite Senior Member
    Messages: 616

    Armour stone is 165 or 185 lbs per cubic ft. One or the other, I don't know if this would apply. But it works for cubical stone anyways.
  4. Kate Butler

    Kate Butler LawnSite Senior Member
    Messages: 640

    Granite is 167 lbs./cu.ft. Here is a link to a calculator for the volume of spheres. Once you know the volume, you can figure the weight easily.


    It would be useful to know what the composition of these boulders is. BTW, where I live, something that size would be called round rocks - boulders are bigger than 3'-4' diameters.
  5. Stillwater

    Stillwater LawnSite Platinum Member
    Messages: 4,889

    you need to go to your rock yard and become familiar with their standardized sizes, take your measurements with you. it is part guess work, if we are talking about huge boulders custom select them to meet your measurement needs. read kate butlers post again
  6. allinearth

    allinearth LawnSite Senior Member
    Messages: 614

    What are you having to pay for those granite boulders in your area? per ton?
  7. allpro2009

    allpro2009 LawnSite Member
    Messages: 20

    1-2 footers are 140.00.
  8. allinearth

    allinearth LawnSite Senior Member
    Messages: 614

    140 per ton or a piece?
  9. allpro2009

    allpro2009 LawnSite Member
    Messages: 20

    140 per ton of "1 to 2 footers" as they call them. when i asked him about how many boulders i would get within that ton, he explained he didnt have any idea...from 20 to 40. so, as you can see, its looking like im just going to have to order a few tons and sell any leftovers into another landscaping job. i will also note the amount from each ton, and keep using the same distributer so that in the future, i can have a better idea of the volume and length, verse weight.
  10. JohnnyRoyale

    JohnnyRoyale LawnSite Senior Member
    Messages: 616

    Can you go to his yard, and see what a ton will get you?

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