Update: Dug up rotted deck, need advice preparing soil for patio pavers

I'm trying to build a paver patio but after digging up my old rotted deck I have some new questions. Here is my original thread Looking for advice on building a ground level deck OR stone paver patio

So as I learned, and you can probably tell, the deck was built in 2 sections by 2 different people. The soil on the larger part is pretty straight forward and largely untouched. The person who built the smaller portion dumped about 6-8 inches of stone mixed with soil under the deck for drainage. I'm assuming I will have to remove all the stone and replace it with soil before I add the sub-base, correct?

That 'box' turned out to be electrical running underground to the deck in my back yard. No I haven't dug yet and yes of course I will have utilities marked first, but I just want some feedback first to see if I'm wasting my time proceeding. If I'm clearing out the rock and adding soil, will I be able to run a plate compacter on top of the utility line?

And finally, if I do move ahead, what is the correct way to slope this patio? I have attached a picture with my grading issues. Normally you would just slope away from the house, but the top part of the patio would run directly into a small hill. If I slope diagonally, I have a 30ft span from end to end which would give me a 7.5 inch different from end to end using 2 inches per 8ft? That sounds pretty extreme. Any tips?

 

You can check out YouTube videos but basically the next step is to remove 8-10" of soil and replace with limestone in 2" layers compacted with each application.

This is the critical stage, without the proper base you wont get the drainage needed or the structural support to keep it flat over the years!

 

Utilities probably will not mark the power line connecting to your deck. They will only mark utilities going to your house. Where they go after that is on you.

The whole back side of your house seems very low to the ground. Any way you can grade your back yard and get more elevation to work with? It appears you patio height is going to be very close to the siding which means wood. With a patio or ground level very close in elevation to the siding and wood structure behind it is difficult to keep the wood from getting wet.

You will need to re-grade the portions of your yard that are sloping to the deck if you want to keep that water and dirt off your new patio.

Sloping the patio perpendicular to the back of the house is the easiest to calculate and construct.
You can slope your patio diagonally though it will require more thinking and it will be harder to control your elevations.