1. Missed the live Ask the Expert event?
    Not to worry. Check out the archived thread of the Q&A with Ken Hutcheson, President of U.S. Lawns, and the LawnSite community in the Franchising forum .

    Dismiss Notice

Geogrid is it necessary?

Discussion in 'Hardscaping' started by LawnMan883, May 13, 2007.

  1. LawnMan883

    LawnMan883 LawnSite Member
    Posts: 85

    i know this has probable been asked before but i did a search and could not come up with a solid answer. I am buinding a 32 foot long wall, highest section is about 2.5 feet high, and it will taper off to about 2 courses on the other end.. the soil has a sandy texture and will be backfilled with black dirt. In this type of application is geogrid necessary? I do have fabric to put behind the wall, and a load of 1" crushed stone for drainage. Is the 1" crushed stone also ok for under the wall or would something else be better?
    i have built only 1 other wall before and it was not as large so I di dnot use geogrid or fabric, but a lot of stone and it seems to still be holidng well. I am just concerned to be sure i do this one right.
  2. Lite4

    Lite4 LawnSite Gold Member
    Posts: 3,112

    Most manufactures will spec. geo-grid when the wall heights start to hit around 3.5-4' tall. Check with the engineering specs for the type of stone you are using. To answer your question, Most walls under 2.5' are ok without. However you will need to provide drainage behind the wall to eliminate the wall bulging in the winter due to the freeze/thaw cycle, and to keep any hydraulic pressure off the back of the wall from rain and irrigation water. Use a good road mix base 6" deep and compact well. Then use a sand or fine pea gravel to use a leveling medium for setting your base course. Also Put a layer of quality non-woven geo-textile fabric directly behind the wall. This will keep any debris from flushing through and will keep the front looking clean and neat. my $.02
  3. Mike33

    Mike33 LawnSite Bronze Member
    Posts: 1,649

    Im not going to mention ncma standars for grid because i disagree and build stronger. How ever my man. says every 3 courses so that is what i do and allow that in my price structure. Follow the previous post on stone for backfill. A wall that size i would backfill completly with clean stone.
  4. DVS Hardscaper

    DVS Hardscaper LawnSite Fanatic
    Posts: 6,417

    I do not think there is a single person here that can answer your question.

    The 4' rule is for a *perfect world*. And thats a fact! If everything was *perfect* then a wall would not be needed.

    I have only had one wall fail ever.

    And that wall was 3-feet high! And we did NOT use grid initially.

    Wanna do it right?? Consult with a retaining wall engineer.
  5. etwman

    etwman LawnSite Bronze Member
    Posts: 1,466

    Geogrid is never necessary. You can build any wall without geogrid, It just depends on how many times you want to re-build the wall in the same spot and how much free time you have.

    Every job is different.

Share This Page