Let me start by saying I know nothing about granite. What I would like to do is lay a piece 55"L x25"W x4"D in front of my outdoor flagstone fireplace as a hearth.I have grey bricks around the face so I'm thinking it won't look too out of place with all that flagstone. I poured a 2x6 pad today at the same dimentions to ground level today and planning to set the granite on the pad once it dries and I convince my buddy to help me move 500+ pounds to my house. It seems to me it would need something between the two surfaces as a barrier, maybe thin set mortar or whatever, does not seem like 500#s would move or shift but I'm in Illinois so I want to be sure because I sure don't want to move it again once it's set. Any help appreciated