Behind retainer wall

Discussion in 'Hardscaping' started by Redbear, Oct 14, 2006.

  1. Redbear

    Redbear LawnSite Member
    Messages: 28

    Using Navastone wedgestone & wallstone combination along a driveway. The wall is no more than 15" at it's highest point and most less than 12". The engineering drawings for this stone suggest that compacted B gravel behind the wall 15" width behind is all that is required. I'm used to putting clear fill in fabric behind walls and drainage if necessary, not so for this wall. Can anyone reason for me why the engineers would be putting compacted gravel behind the wall, no fabric. This is suggested for many of their wall constructions even up to 3 ft in height. I am in a climate of heavy frost and winters. Could it be that the compacted gravel will not have the voids for frozen water to expand and push on the wall?? I'm certainly no engineer but would like to better understand the reasoning on this one.

  2. Mike33

    Mike33 LawnSite Bronze Member
    Messages: 1,649

    I think that is there reason. Also i have many walls out here varing in height and even if it is only 2 courses i put clean aggregate behing them. You could get some mud seaping thru from fill.
  3. RockSet N' Grade

    RockSet N' Grade LawnSite Silver Member
    Messages: 2,454

    The simple answer to me would be to call the engineer and ask them their reasoning.
    The idea of installing a fabric membrane to keep the gravel clean over time, from my point of view, is the right thing to do and I would prefer to do it that way.
    We just had a wall (2500 sq. ft.) and the engineering at first glance looked absurd, so I hired an engineer who specialized in walls to review and reccomend and then redesign the retention system. After it all shook out, I found out the first engineer had never been to the site and it was his first job that he had ever designed. By paying the second engineer $700 for his new stamped drawings, we ended up saving over $8,000 in labor and material, and had a better end product. You just never know......give a call to the engineer, they should be willing to talk to you and answer your questions.

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