Alright, heres my question for you all. I am finishing my backyard at my personal residence, thought maybe you guys could give me some advice on a few things. First, I am building a grill center. The body is going to be built out of cinderblocks, not sure yet what I am doing for the exterior. Anyway, I am getting ready to lay the base for this grill center using cinder blocks. Heres my question: Should I do one layer or two layers of cinder blocks? I will be staking it with rebar and am not sure if one layer is deep enough (cinder block is 7.5-8" deep). A friend told me I need to do two layers in case of frost in the winter/ ground moving. Comments???? Secondly, I am laying a patio also. For the base I had calculated 4" crushed limestone, 1" coarse sand, then pavers. Is 4" base enough? I've heard some guys on here say yes, others no. Its supporting only foot traffic/ patio furniture, no cars or anything. One last small thing. For the grill center base I am using cement, and for the rock retaining walls I am using mortar. Sound right?? Thanks in advance guys, appreciate all the input!