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Big stone in raised patio

Discussion in 'Hardscaping' started by ZX12R, Oct 17, 2007.

  1. ZX12R

    ZX12R LawnSite Senior Member
    Messages: 787

    My neighbor had his deck removed and is having a raised patio installed.The patio will be about 4' off the ground.The contractor used 1-3" stone as fill.He said it won't settle as much as 3/4" clean stone.On top of that,he put 3/4" clean stone and ran a vibratory plate over it.

    My question is,do you think this was the right thing to do using the larger stone as a base? By the way,he used a solid 3' of it ,and none of it was compacted.Will it settle and move over time?
  2. LB1234

    LB1234 LawnSite Gold Member
    Messages: 3,208

    You can do the larger stone on the bottom. Only problem I see with it is that the smaller stone will tend to mitigate into the larger stone over time (i.e. settling)...especially if a seperation fabric of some kind was not used. So yes, the stone will most likely settle over time. And if he didn't compact the large stone that may settle as well. Not sure what size the larger stone is/was. As for the 1-3" stone, it depends on the size of the compactor that was used and how many lifts he had done the compaction with.

    You could have a nuclear density test done to see what the compaction is. This will give you a real good idea of how "compacted" it is.

    I'll be interested what others with more experience with this have to say.
  3. McKeeLand

    McKeeLand LawnSite Senior Member
    Messages: 681

    its my understanding that 3/4 is almost fully compacted when it is just dumped in place. fill a 5 gallon bucket up with it and see how far you can compact it down, not far. but my thoughts are similar to LB1234". I am sure it can work, just seems like it is unnecessary and difficult to work with.
  4. cgland

    cgland LawnSite Bronze Member
    Messages: 1,929

    This is one of the biggest wives tales around. There is no way you can measure the compaction of clean stone.....no way! There are no existing tests that can prove such a statement. I have seen 6" lifts of clean stone that compact 2" and I have also seen 6" lifts that barely compact at all. It all depends on the gradation, sizes, etc. Let's not fuel this misinformation any longer.

  5. McKeeLand

    McKeeLand LawnSite Senior Member
    Messages: 681

    like i said this is my understanding as it was presented at MAHTS this year in a raised patio seminar. i would never not compact 3/4 clean no matter what the circumstance. but i do think in general that you will get far less movement in 3/4 than in a modified or QP, this is why EP Henry specs it as the back fill in there over dig stabilization which is 40" deep.
  6. cgland

    cgland LawnSite Bronze Member
    Messages: 1,929

    Actually, the reason is two fold , clean stone will not put as much pressure on the foundation wall as modified will, plus clean stone will drain better.

  7. zedosix

    zedosix LawnSite Silver Member
    Messages: 2,653

    We have on numerous occasion used 2" minus for the base of driveways or over digs. Always compacted it in 1' layers with a diesel vibratory plate (1100lb unit). As I recall it certainly did compact. I think the contractor may of been rushing things.

    Not the way I would of done it.
  8. Mike33

    Mike33 LawnSite Bronze Member
    Messages: 1,649

    we have washed and unwashed clean stone , i have seen the difference there. I have heard that clean 57's was supposed to be like 99.3% self compacting thats bull crap. I use at times 57's in wall base and they sure drop when the plate tamper runs acrossed it. Funny thing 1 time at my wifes apartment complex she manages, they had a cont. excavate for broken sewer line. They dug around 18' deep when fixed the guy said he was going to dump it full of 57's since they was self compacting then he could replace black top right of way. i had to advise my wife on compaction and he about shiped his pants when my wife stood and told him how to correctly do it.
  9. ChampionLS

    ChampionLS LawnSite Bronze Member
    Messages: 1,066

    You can use any larger stone under smaller stone. It's called a Sub-Base. The larger stone don't really need to be compacted as their naturally larger size don't tend to settle. The smaller the particle size (I.E. Sand) will compact the most. It's not that common in every day hardscaping to use a sub-base, but you will find them in the I.C.P.I Tech Specs and are more commonly used in the building of roadways.
  10. ZX12R

    ZX12R LawnSite Senior Member
    Messages: 787

    "It's not that common in every day hardscaping to use a sub-base, but you will find them in the I.C.P.I Tech Specs and are more commonly used in the building of roadways."

    The contractor did say that the larger stone was for "roadway" use.

    He put 3/4" clean stone on top of that.....compacted that....put a fabric over that......put stonedust over that....compacted the stonedust.......screeded that.......and applied pavers.

    He did not fell the need to run a vibratory plate over the pavers.

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