Question
Sean,

The driveway on the property I just purchased reaches quite far into the middle of the property.  The driveway is composed of  crushed, course rock and bordered by grass.  I would like to reclaim some of the driveway space for a patio area and am considering installing 20inch X 20 inch concrete pavers.  The pavers would be installed about seven inches apart in a basic grid pattern and I would keep the existing course rock as the filler for in between the pavers.  The area is about 12 feet x 23 feet in total.

Since the oringal driveway was already prepared to accept the course gravel, I am thinking that all I would have to do to lay the pavers in place would be to dig out the gravel and place the paver down in place.

Does this sound like a good plan, or would you still recommend using sand?  The thing is that since the pavers are not going to be butted up against one another, and the sand would only be under the individual paver, it seems to me that that wouldn't be very effective.

What would you recommmend?

Thanks!

Thomas

Answer
Thomas:
It is really hard to evaluate the base preparation just from this description. I suggest your use a shovel and check a few places to be sure the gravel and base is fairly uniform and well compacted. If you find that it is thin in places it may not make a good base. However, if it is good then you can use it as a base.  Sand is used as a leveling course. It allows you to place a paver on the sand and then tamp it into place. The sand helps lock the pavers in place when placed adjacent to one another. So in your case sand is not absolutely necessary but it may still make leveling the pavers easier. If you don't use sand I suggest adding a 1 to 2 inch layer of decomposed granite (AKA granite dust, granite fines or M10)over the gravel base and then compact and level it with a  hand tamper. You can make a hand tamper by cutting a 12x12 inch piece of 3/4 inch plywood and screwing it to the end of a 2x4.
You can then place the pavers on the granite fines and tamp into place.
One thing I would caution you on is having part of the patio over the old driveway and part over a new area that has not been prepared in the same way. This is because it is almost certain that one will settle more than the other resulting in a warped patio. So I would strongly urge you to dig out all the old driveway to the same base grade and treat the sub-grade for the patio with the same base preparation across the entire patio area.
I hope this helps.

Best of Luck
Sean J Murphy, RLA, ISA, LEED AP
Please check out my landscape websites for more tips and ideas on landscaping.

http://www.seanjmurphy.com
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