A customer has an existing bluestone patio (aprox. 18'x 25') the pieces are all different sizes and several are cracked from a truck driving on them many years ago. she wants to pull the existing product up and redo the patio using what is still good and adding some new pieces. I am planning on excavating the base out to a depth of 5-6 inches and adding compacted RCA and then an inch of sand to set the bluestone in. is this a bad idea? any other suggestions on what I should do for a base?