I second what Trunk says.
Quite a few years ago I wanted to add a outdoor spa next to my existing concrete patio. All I needed was a 10x10 foot smooth flat floor to set the spa on. That area was presently a lawn that I thought was almost perfectly flat. One side of my square would be against the house, one side against the existing patio, and the other two would extend out into the lawn.
Being a young, strong DIYer, I decided to make my own spa base. I would use concrete planter edging on the 2 outside edges to enclose the area, pea gravel to level the area, then lay 12"x12" plain concrete pavers to form a 9x9 solid floor to set the 8x8 spa on. Once the spa was set on it, there would be no traffic to disturb the pavers & hence no need to grout, etc. Sounds sensible & easy, right? Right? RIGHT???
WRONG. Totally Wrong.
First I bought the 20 feet of edging and 81 pavers, cost about $200 in 1990. Good thing I had a truck since that all weighed about 400 lbs. I also bought 5 20 lb bags of pea gravel at the usual insane price for small packages at the big box store. But since I wouldn’t need much, the high price per bag was only wasting maybe $20, right? That was another hundred pounds to load/unload 4 times.
Set up the edging, added the 100 lbs of gravel & it looked like I’d dropped a teaspoon of sugar in a bathtub.
Got serious with my level (waay before lasers it wasnt easy for a DIY to accurately determine level across a 10 foot span). Turns out I had about a 4" slope in that 10 feet, 6" drop across the diagonal. It was very smooth & regular which is why I hadn’t seen it before. Whoever graded the yard for drainage had done a very nice job.
TO shorten the rest of the story … I had to build a dike 8" above grade at the low point to hold the gravel. I used oversized pavers buried on edge. It wasn’t as pretty as the origonal edging; in fact it looked like crap.
Then it took 1 TON of gravel to raise the bed to level. At least I was getting smarter & had a real gravel company deliver a dumptruck load to my driveway.
So after a couple hundred more bucks more into the project & 3 weeks of all weekend work & all week soreness I have a crappy looking bed for the spa.
So all’s well that ends well, right? Not really.
For the remaining 3 years we lived there we had problems with the lawn growing up through the gravel & also the bed subsiding here & there. To “save effort” I’d just buried the lawn under the gravel rather than removing it. Instead I spent all that effort & more shoring up the results.
Remember, this was a “patio” with no traffic on it. This was also in Vegas where there was no drainage or freeze problems to contend with.
Bottom line: the ONLY sucessful way to make a patio is the real way: Guys come in, remove the lawn, place a form, and pour real concrete and level it. Or they come in, remove the lawn, build a multil-layer bed with proper drainage & set real paving blocks, not stepping stone squares misleading labeled “pavers”.