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Terrace Wall Installation

Discussion in 'Landscape Architecture and Design' started by stelon, Dec 16, 2004.

  1. stelon

    stelon LawnSite Member
    Messages: 6

    I'm installing a series of 4 Terrace Walls on a down hill slope. It's a basement lot home, so the grade drops approx. 10-12 feet from top to bottom. The length of the slope is approx. 35-40 feet.

    Here are the specs on each wall:
    7' x 1' high, first course buried- 28 stones
    4' x 2' high, " " - 28 stones
    6' x 2' high, " " - 42 stones
    7' x 3' high, " " - 70 stones

    Crushed rock base, and I will back fill with top soil and gravel. Estimating 2-3 yards of soil.

    Wall base will be hand trenched and dirt moved by wheelbarrow and hand.

    Total cost on materials will be approx. $512.
    Labor @ $768

    Estimating that it will take a total of 12 man hours. I would like thoughts and comments on the time to complete the work and price on the labor.

  2. D Felix

    D Felix LawnSite Bronze Member
    Messages: 1,898

    Keep in mind that terraces are not an average wall.

    I believe most specs from manufacturers state that to keep an upper wall from bearing on the lower wall, it must be 2x the hieght of the lower wall behind the lower wall. In other words, if the lower wall is 2' high, the next wall must be at least 4' back from it.

    If you've got walls that are spaced closer than that, you need a lot of geo-grid, which requires a lot more than just hand excavation.

  3. kris

    kris LawnSite Bronze Member
    from nowhere
    Messages: 1,578

    Take note of what Dan is saying ....

    What type of block are you using ...curved wall, straight, access are only a few ? 's that come to mind this early on a Saturday morning.

    I believe you are low on your time estimate. Don't cut yourself short.
  4. cgland

    cgland LawnSite Bronze Member
    Messages: 1,929

    You really don't need geogrid in this application as the walls are only 2' tall and not retaining that much.(you will on the 3' one) There are a couple of things that you left out though........caps, glue, drain tile, separation fabric and clean drainage stone. This stuff will add up quick. I would hate to see you take a bath because your price is already rediculously low. Just my .02

    D Felix That spec is meant for engineered or load bearing walls, not garden walls.

  5. kris

    kris LawnSite Bronze Member
    from nowhere
    Messages: 1,578

    Chris ....the guy doesnt give enough info to give really any kind of educated feedback too. What I see is 8' total height of wall. Who knows if he is even using the correct type of block. There are plenty of wall blocks that shouldn't be used in applications over 2'
  6. D Felix

    D Felix LawnSite Bronze Member
    Messages: 1,898

    I know those specs are for bearing walls. What he was describing sounds like a classic bearing terrace situation to me, which is why I told him what I did. I didn't say he needed grid, just that if they were not spaced far enough apart then he would.

    Basing everything on the first wall he lists, he's using Windsor-type garden wall block, 12" wide x 4" tall. I don't think ANY manufacturer of those blocks suggests walls being built over 2' tall. From that, it looks like he needs to go back to the drawing board and probably use different block and do it right from the start.

  7. cgland

    cgland LawnSite Bronze Member
    Messages: 1,929

    I assumed he was using EP Henry Terrace wall(16"lx6"h), which you can install up to 3' w/o grid. It sounded to me as if he was building terraces against a house, going from the front yard down to the back. :dizzy:

  8. steve in Pa.

    steve in Pa. LawnSite Senior Member
    Messages: 294

    even if he was using terrace wall he would still need geogrid if the terrace's were not back at the LEAST 2x the height should be 3x technically. If the terrace's are not back the min. your terraces are still one load bearing wall being 8' in height. those little walls add up to one big one if not done correctly.
  9. GreenMonster

    GreenMonster LawnSite Silver Member
    from NH
    Messages: 2,702

    Dan is likely correct. These are prolly NOT retaining wall block. They are garden block for tree rings and cute little gardens.

    As some others have said, if he is not spacing the walls far enough back from each other, he is creating a load bearing wall. His garden walls will quickly become retaining walls based on the terraced dimensions, then, equally as quickly, they will fail :(

    If the 2x height set-back specs mentioned in Dan's orginal posts are not being used, then definately, consider a true retaining wall block.

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