Nick Maclaren wrote:

You can take short-cuts if you know what you are doing (I did), but you
won't go wrong following that site. The main short cut is that you can
reduce or eliminate the sub-base if you can GUARANTEE no motor traffic
and your soil is mostly sand or gravel - you still need to compact it,
of course.


Regards,
Nick Maclaren.

My patio is slabs laid on sand laid on the earth underneath. They've
moved a little bit in twenty odd years but otherwise are fine. I've
got heavy clay soil where I am.