compactability of gravel and sand

Discussion in 'Hardscaping' started by Keith P, Mar 21, 2005.

  1. Keith P

    Keith P LawnSite Member
    Messages: 28

    If i want to end up with 4 inches of compacted gravel for base and 1 inch of compacted sand for paver base, roughly how many inches of uncompacted material will I need?

    Thanks for your guys' patience with my questions I new to hardscaping.
  2. Dig-it Landscaping

    Dig-it Landscaping LawnSite Member
    Messages: 108

    i remember in school we were told that 1.25" of chips and dust gravel compacted to 1". sorry i cant help on the sand
  3. zedosix

    zedosix LawnSite Silver Member
    Messages: 2,665

    Since there is very little air space between the grains of sand, it would have very little compaction.
  4. WhohasHelios?

    WhohasHelios? LawnSite Member
    Messages: 233

    It all depends on which specific type of material you are using. To say sand and gravel isnt really specific enough for the industry here anyways. 3/4" minus (road base) will easily compact about an inch and a quarter or so. So you would need that much more than your desired compacted levels.

    Sand I will assume you are using masons sand of some sort ( washed sand) it does not compact nearly as much as someone already pointed out due to less gradation in the size of grains.

    Hope that helps,

  5. YardPro

    YardPro LawnSite Gold Member
    Messages: 3,570

    STRONGLY advises against compacting the sand before the pavers are laid.
    compacting the pavers into the sand will give you a 3/8" settle, and will push sand up between the pavers and lock them together.
  6. WhohasHelios?

    WhohasHelios? LawnSite Member
    Messages: 233

    I remember my dear old dad used to do it that way when I worked with him. It was always a huge deal to screed the sand out completely evenly and then not step ANYWHERE on the prepared surface.

    When I started up, I had a few paving jobs that I did that way, and then on one of them I had a guy working with me...He stepped on the prepared base after screeding the sand a year later there was a dip in that spot...Since then I have switched to compacting the sand as well as the aggregate.

    Is the sand coming up though the bottom the only reason for not packing sand or are there other reasons we should be doing it this way?

  7. zedosix

    zedosix LawnSite Silver Member
    Messages: 2,665

    You are defeating the purpose of "interlocking" if you compact before laying the brick. Why wouldn't you of taken a few seconds to level the "dip" before laying the brick?
  8. dylan

    dylan Member
    Messages: 276

    I usually increase the amount of fill required (volume) by 20% to allow for compaction.
    It also works in reverse. When you excavate a hole, the material will get bigger by 20% when you go to take it away.
  9. YardPro

    YardPro LawnSite Gold Member
    Messages: 3,570


    why would you not just use a 12" hand trowl to fill in the dip????

    EVERY paver manufacturer will void thier warranty if they find out that you compacted the sand base BEFORE paver installation.

    also the advantage to compacting after is that IF you have any unlevel areas, they can be fixed with the compactor. just run over the higher areas a little more.

    the main reason to compact after is so that you can push sand up between the pavers and get a good LOCK. when you sweep sand in from the top, you will have a lot of areas that sand does not entirely fill the gap. the voids will be at the bottom of the pavers. with compacting after pavers are laid, this eliminates this problem by filling the bottom area with sand.
  10. WhohasHelios?

    WhohasHelios? LawnSite Member
    Messages: 233

    Of course we did !! But the rate of natural compaction in that spot compared to the rest of the sand was then comprimised. Hence the problem...Of course I did not just look at the dip in the sand build on top of it!!!

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