A paver project can be a lot of work for a patio or sidewalk so you don't want your paver bricks to become uneven or loose. It is not a comfortable feeling knowing that you will have to redo sections of the patio or sidewalk so it is wise to place as much thought into the foundation as it is into which paver bricks look best around you home.
The paver base should be applied next to the ground. Allow enough depth for the paver base and the leveling sand that will be applied on top of the paver base so that the finished patio or sidewalk is leveled properly. The amount of paver base material needed for your project will vary depending on the thickness. I applied a thicker layer of paver base when I built a patio for my home. I figured a little extra cost up front would provide a solid foundation. I install the patio at my home in 2008 and it has not shifted at all.
The paver base material looks and feels similar to ground up paving material used to pave roads. I would imagine that the material over time will harden to become a rock solid foundation, although I am not going to dig up the patio just to find out. What I do know is I am glad that I took the extra time and expense to prepare a solid foundation.
I used Greensmix paver base material for my patio project. You may not know that I installed a paver base foundation under my patio project when you are standing on it but chances are you would know it if I did not. Install a paver base layer under your patio or sidewalk project for a solid foundation and peace of mind.