We are planning a new deck and patio for next year’s spring project. Our contractor suggests installing the stones over the current concrete patio (and expanding it with more concrete as a base) while the stone supplier says the old patio should be removed and a bed of stone etc should be the foundation for the new patio. We live in the northeast where every kind of weather will be a factor. Who has had a successful experience with this kind of installation? We’d love opinions on this debate.