Do not know your area but before you put in a base , you should first compact the dirt the base will be put upon.
If the dirt compacts easily you can probably get away with a 4 inch base but more is always better.
Obviously you will have to dig out and haul away some dirt but then put in 1 x 2 x 8 inch steaks .
Set them level and to the drop you want , 1/2 inch from the house to the edge is more than enough,
I use 4 to 8 foot 1/2 inch steel water line pipes, A: to gauge if they are level side to side B: if the drop from top to bottom is what I want.
Add crushed rock till it is to the top of the stakes, continually compacting, then lay the rods and screed dry, reapeat dry sand with them.
Remove and fill in the pipe gap as you lay.
After laying , them you must compact the bricks and rake dry sand to fill in the cracks.
They should drop about 3/8ths of an inch so take that into account when putting the stakes in.
