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Retaining Wall Base

Discussion in 'Landscape Architecture and Design' started by SpringValley, May 3, 2001.

  1. SpringValley

    SpringValley LawnSite Member
    Posts: 147

    I know there was a thread some time ago about the base for a retaining wall. The general conscensus was to use crushed limestone with a lot of dust in it to get it to compact well. Has anyone ever used pea gravel? It is 95% compacted when you shovel it into the hole. As long as it is contained within the trench it cannot go anywhere and the leftover (you always try to have too much) can be your drainage rock behind the wall. I am building two walls, one 12' long by 3' high, and the other is 16' long by 4' high using Keystone Compacts (80# each). I am extending poured concrete retaining walls on a new house.

    Let me know your thoughts on the pea gravel. I am working on this project this afternoon.

  2. SCL

    SCL LawnSite Senior Member
    Posts: 543

    No no no no, to pea gravel for base. You need a course aggregate that can lock together and be stable. All wall mfgrs that I have seen say do not use pea gravel. Consensus used to be 3/8 to 3/4 chips but road rock (CA6) is spec'd now. It will work for the drainage but its expensive. Check with your rock supplier or contact me for more info. Also, look up Paul, cause this guy knows this stuff inside and out.
  3. SpringValley

    SpringValley LawnSite Member
    Posts: 147

    Thanks for the reply. I thought about it briefly and just wanted a second opinion. I will use limestone with dust so it will lock together and form a solid base. I will have to hand tamp it though about every 1-2" to make sure it is solid.

  4. Stonehenge

    Stonehenge LawnSite Bronze Member
    from Midwest
    Posts: 1,277

    Just for emphasis,

    NO on pea gravel for a base. Never.

  5. SpringValley

    SpringValley LawnSite Member
    Posts: 147

    The pea gravel was just an idea. I was able to complete the first wall last night and it went well. I used #13s (all areas of the country are different) which are 1/2 to 3/8" limestone with lots of fines and dust. I compacted it every 2-3" for a total of about 8" deep footer. It looks great.
  6. paul

    paul Lawnsite Addict
    Posts: 1,625

    I know this is late in posting but......
    take a shovel full of your pea gravel place it on a concrete side walk, now put your foot on it, it moves right! Well your wall will too and not the way the manufacture wants it to. They are like marbels rolling all over the place, and so would your wall. As for 95% compaction not likely might be ok for a large slab with out any forces on it, contained by foundation walls but not something like a retaining wall with something pushing on it!
  7. Rex Mann

    Rex Mann LawnSite Senior Member
    Posts: 621


    Do not use the pea gravel for your drainage material. You need to use a clear angular stone. We call it #57 limestone. The angles allow it to "lock" together. The backfill of the wall becomes part of the wall. And, you do not want any parts of the wall moving on you.

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