# Putting 2A gravel on top of 2B gravel for better drainage?



## BrandonC_1972 (Apr 28, 2012)

Let me first start with my area calls crushed 3/4 limestone 2B. They call 2A limestone 3/4 that has the fines/dust in it. I believe others call this #57 and CA6 respectively.

I am considering using some 2A (3/4 with fines) crushed limestone on top of 2B (3/4 no fines) to help promote drainage for my paver patio. The only disadvantage I see to this is that over time the fines could work their way down to the bottom and not promote this drainage as well as affect the base and cause the pavers to settle. Should I be concerned? Is this something worth doing? Am I required to be another layer of geotextile on top of the 2B to avoid the 2A from getting into the 2B? Is any of this worth the effort?


More detail...

I am building a paver patio that has a natural grade that slopes away from my house but also ends where my pool concrete starts, so I have installed some french drain and channel drains. I've excavated so that the slope goes away from the house and away (for the most part) from the concrete to make a V.

My thought was that I would lay a 2-4 inch layer of 2B 3/4 gravel on the very bottom to help promote drainage. This layer will actually be 6+ inches around the perimeter where wall block will be placed. I would basically cover the 4 inch corrugated drain pipe that sits at the low point with the 2B gravel.

I would then put the 2A 3/4 with fines gravel on top of all of this to provide a firm/even base for the pavers. This 2A layer will be at least 8 inches and in the area where I excavated the most to make the slope as much as 20+ inches.

I will be using a plate compactor in 4-6 inch layers/lifts.


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## Bondo (Dec 8, 2007)

> My thought was that I would lay a 2-4 inch layer of 2B 3/4 gravel on the very bottom to help promote drainage.


Ayuh,.... Forget the 3/4" washed stone, 'n use the 3/4" minus from the get go, 'n Compact it every 2" or less....

You don't need drainage in the sub-base if the finish grade is pitched properly...


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