need help for base of a retaining wall

Discussion in 'Starting a Lawn Care Business' started by mowermonkey, Nov 10, 2004.

  1. mowermonkey

    mowermonkey LawnSite Member
    from ohio
    Messages: 8

    This is going to be my first retaining wall by myself. I was wondering if someone could enlighten me on how to figure out how much base to use.
    Is there some type of equation of some sort. If some of you could give me an idea or an idea where to look it would be greatly appreciated.
  2. GreenMonster

    GreenMonster LawnSite Silver Member
    from NH
    Messages: 2,702

    A little more info please. Are you solely looking to figure out tonage needed for your base? The size of your base is dependent on the size of the block. The depth of your base is dependent on the height of the wall and possibly, other specific site conditions.

    Some OEM specs call for 3/4" stone, others call for 3/4" crushed gravel. Some guys here use their own special recipes for base (some of which sound pretty interesting).

    What are you using for wall stone?
  3. mowermonkey

    mowermonkey LawnSite Member
    from ohio
    Messages: 8

    the size of the block is 12''w x 4" H x 8"D, The customer is purchasing the retaining wall block from lowes. It is the oldcastle castlewall stone. The wall is going to basically be 2' h x 30' long. Basically yes i think that is what i am trying to figure out is tonage i need.
  4. GreenMonster

    GreenMonster LawnSite Silver Member
    from NH
    Messages: 2,702

    to give you a base that is 30' x 16" deep x 4" deep, 1 ton should be more than enough (actually comes to about 1/2 ton). I usually go with 3/4 crushed stone. A little concrete sand can be used to make it easier to level out the base course.

    I'm not sure, but this sounds more like a garden block -- it may not do the job as a "retaining block". You might want some drain stone and drain tile behind the wall as well, or look into a retaining wall stone product if that is truely what you are trying to accomplish. If that is the case, I would point you to a masonry supply shop, or other supplier or hardscape products. They'll also do a better job of pointing you in the right direction as far materials you need, base prep, etc.

    HTH, good luck.
  5. CuttingCrew

    CuttingCrew LawnSite Member
    Messages: 193

    I use DGA (dense grade aggregate) compacted with a vibratory plate compactor for the base of all my Allen Block style walls. Figure how much we need sq. ft. wise, L X W X H in feet. When we know how many cubic feet we need were done. Purchase 120 lb. Per cubic foot.

    We fill the blocks and back fill with “57 chips” (one to two inch chipped lime stone) for drainage.

    Anything over four feet high should get input from an experienced engineer and some Geo-Grid.

    Make sure your Bonded before doing any retaining wall work.

    Good luck, have fun. (I do love building walls)
  6. wagner17

    wagner17 LawnSite Member
    Messages: 67

    CuttingCrew is absolutely correct. I used a DGA on my wall as well. It is a very difficult undertaking if you have never built a wall before, especially if you are doing it alone. My best advice is after laying the foundation to make sure that the first row is LEVEL. That is the most important part of the project IMO. It was hard, but it is very fulfilling and a beautiful product when complete.

    JKOOPERS LawnSite Bronze Member
    Messages: 1,259

    you might wanna start at the lowest point in the wall. its easier to step up than step down .
  8. New Green

    New Green LawnSite Member
    Messages: 57

    I was looking into a retainer wall myself. Thanks for the posts and the info. I can't get enough of the Fenway celebration. Great pics GreenMonster. I still feel like I must have been dreaming. Go Sox!
  9. NNJLandman

    NNJLandman LawnSite Bronze Member
    Messages: 1,306

    I think we usually dig about 7 inches down you'll have to figure out how deep your first block will have to be burried first though. Qp about 4 inches then compact it, then sand about 2 inches. We lay out a couple of feet at a time. Screed the sand works out pretty good were able to lay about 9 block at once. Good luck, run your pipe behind the wall and backfill with 3/4 clean, for higher walls geo grid or compact the 3/4 clean.


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