I am planning a paver patio, about 40'x20'. There is some 3/4" river rock in the area now. I am planning on removing the river rock and excavating and then placing the proper base material before paving. I am wondering if the 3/4" river rock could be used as a subbase ? If not I will just haul it away, but if it will work I would use it. How deep should I excavate, can the river rock be used and how deep should the sand be. ANy other tips or advice is welcome since this is my first paver project.
Well lets go a little further and instead of blurting out "no" or "yes" lets explain WHY!!! Folks, in terms of business I am big on explaining. I explain EVERYTHING to our clients. This is what displays competency which is what closes a deal. The river gravel should be removed. And the reason why is beacuse river gravel is rounded. See, a crusher run aggregate is angular. The angular shapes lock the aggregates together. Think of a gumball machine. Push on on gumball and it will cause the other gum balls to roll around. This is NOT acceptable for a pavement. You want the aggregates to be firmly locked together. We excavate 8-inches for our pavements that are used for pedestrian purposes. We install and compact 5-inches of CR8 base, that is 5-inches after compaction. Compacted in 2 inch lifts. Which in MD CR8 is 3/4-inch crusher run. We then screed 1-inch of concrete sand. Then the difference will be consumed by the depth of the pavers.
CR6 is larger. I could be wrong but I think it is 1-inch down to dust. CR6 is what most roads and highways are constructed with. But for a pavement where you are compacting the base with a plate compactor, I have found that CR6 does not compact as tight as CR8. One way you can tell the difference is when you drive your spikes into base. I have found that I can easily pull the spikes out of a CR8 base with little effort. Where with a CR6 base, it takes some effort to pull them up. If we are doing a driveway, driveways are compacted with ride on rollers. We would use CR6.
If the CR6 has a tighter grip on the spike, wouldn't that mean that it compacts better? If the spike comes out easily, then I would think the base is not as compacted.
We sell cr6 from the travilah quarry in our rockville store. Loads of contractors use it with good results. Our frederick store sells cr8 from the genstar plant off south street. I think the genstar product packs tighter than the travilah product. I attribute this to the genstar stone being somewhat flatter shaped peices, with more medium sized chips & less fines. The genstar product seems to retain a lot less water, it won't tend to turn into mush as badly during times of lots of rain.
It depends on it's moisture content initially. If it is a dry day then yes wet mist the base, but if it is damp or rainy then no. The situation really determines when and how much water to add. Chris
