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Height of Sand After Compaction

Discussion in 'Homeowner Assistance Forum' started by Nullqwerty, Jun 14, 2010.

  1. Nullqwerty

    Nullqwerty LawnSite Member
    Messages: 37

    Hey folks,

    Working on my first big paver project. Using my own home as a guinea pig, by installing 700 sq feet of pavers around my in-ground pool. Two quick questions:

    1) I'll be putting in the standard 1" of sand on top of the base, but how much should I anticipate the height of the sand to be after I lay the stones down and compact them? It's gotta meet up exactly with the pool coping pavers, so I gotta make sure I get this right.

    2) Most areas will be getting 6+" of base...but there is an area that will be getting only 4.5" - 5" of base, because I screwed up during excavation and didn't get enough out (forgive the first-timer here). Before I go out and rent the BobCat again, will I be ok with 4.5" of base in some areas? I'm going for a 1" pitch. This is in Massachusetts.

  2. Paver Gangster

    Paver Gangster LawnSite Member
    Messages: 144

    1. The final thickness of the sand setting bed will be 5/8" if you everything to ICPI standards.

    2. If this is an in ground pool, you may be in for a world of hurt, as typically poured concrete is the preferred base around the pool deck because of lack of compaction of soil around a pool. My advice would be to consult with a ICPI certified installer to complete this job, lest you risk damaging your pool shell with compaction equipment.

    If you aren't going to follow the advice, which you really, really, really, really should if you don't want a big crack in your pool, rent the bobcat, and go 6" all around. May as well since you have not added base.

    Otherwise with differing depths of base you invite areas of the pavement that will settle differently from others, and will be unhappy with the results years later. And, the area around the pool will probably sink 1-3". Not only will your pavement be botched, but all the water in your pool will start leaking out of the crack you made when you put the plate compactor too close to the shell of the pool.

    Hire a professional for this, I beg of you. If that is too costly, then just pour a concrete deck all around the pool, and forget the pavers. You will save yourself tens of thousands of dollars in repairs, trust me.
    Last edited: Jun 15, 2010
  3. ajslands

    ajslands LawnSite Silver Member
    Messages: 2,238

    Isn't 8" for a driveway and 4" for walk way, and 6" for municipal walkway?
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  4. Nullqwerty

    Nullqwerty LawnSite Member
    Messages: 37

    For a pool area they usually recommend the 6". I assume it's because of the extra water traffic. But maybe because of all the plumbing below and the vibrations can loosen the soil/sand surrounding the pipes. Totally guessing here... I think the importance is just because you want to ensure the drainage doesn't get diverted around the perimeter of the pool potentially causing some big issues.
  5. shovelracer

    shovelracer LawnSite Silver Member
    Messages: 2,008

    base thickness is dependent on the subgrade makeup and the area. 4" is not going to last around here with the average subgrade, but each is different. I have needed to go 2' for a simple walkway and have gotten away with 4-6" for a similar in a different location and it held up great. As a rule we now start at 8" and work our way up based on what we find. Each area is different. Driveway minimum here is 12", but better if you work off an additional base of 2" stone under that. Up north they start at 2'. Assuming compaction is right the rest is about loads and how they transfer to the subgrade. In theory your loads drop down at 45* so the deeper the base the larger the area that the load is displaced on. Your subgrade is usually the weak link.
  6. 2low4NH

    2low4NH LawnSite Bronze Member
    from NH
    Messages: 1,890

    4.5" base might not be up to par for mass. Nt sure what the base was if its sandy or clay or just crushed gravel. you should be fine but learn how to use geotextiles they can be your friend here. how long has the pool been in? what type of pool? if its a gnite pool you will be all set but if it was back filled you will have settle around the whole thing up to 15% which could be inches.
  7. Nullqwerty

    Nullqwerty LawnSite Member
    Messages: 37

    Thanks for the help! The pool is a vinyl liner steel pool. It was installed 30 years ago. It had a concrete patio before that I pulled up.

    The subgrade soil underneath was certainly well compacted after 30 years, but I did have to dig 24" deep trenches through it to lay some new plumbing and electrical so it was loosened up. The soil was pretty much fill (dirt with a bunch of rocks). Not sure of the exact makeup of it.

    I compacted the soil and then laid the fabric (figured that would only help). Due to timing and other issues, I hand dug some more around that area and had to go with what I got, so one side will have only 4.5" - 5" base along the last 5 or so feet closer to the edge. It sucks and I'm a little annoyed/stressed about it, but the show must go on. I'm compacting in 1" layers though just to further help the situation and also dampening the base when I do it. Also going with the 1"+ pitch rather than 2" so that I have more base. And again...the pool is 30 years old and had concrete on it that whole time, so maybe I'll be ok.

    If anyone has any further suggestions on how to strengthen those areas to help make good of a not-so-ideal situation, please let me know.

    Last edited: Jun 21, 2010
  8. Nullqwerty

    Nullqwerty LawnSite Member
    Messages: 37

    About 95% complete. Pitch looks like a lot in the attached pic, but it's only an 1.25" over 10'.

    Be gentle here...first paving project. Any constructive comments/suggestions on the attached picture?


  9. 2low4NH

    2low4NH LawnSite Bronze Member
    from NH
    Messages: 1,890

    Is that stone dust? :nono: no stone dust under pavers they will settle over time as the particles break down to fine.
  10. Nullqwerty

    Nullqwerty LawnSite Member
    Messages: 37

    No, that's the base. It's just damp in that picture so it looks dark. I'll be putting an inch of sand over that and then pavers.

    Decided to go with Unilock Brussels Block 80% Sandstone, 20% Terra Cotta, and thin Terra Cotta border around the sandstone coping and perimiter of the whole area.

    Fences will be replaced as soon as the stone is down (most likely this weekend).

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