Base material for Paver Patio

[poudre_lawn]

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.

 

[neversatisfiedj]

Use road base. Do a search - this topic comes up 20 times a month.

 

[DVS Hardscaper]

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.

 

[neversatisfiedj]

I use cr6 , whats the difference ?

 

[DVS Hardscaper]

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.

 

[neversatisfiedj]

ok I will have to see if my yards carry cr8 - I don't think they do - but I will ask.

 

[SharperCut]

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 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.

 

[stoneseller]

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.

 

[neversatisfiedj]

How many wet the base while compacting ?

 

[cgland]

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