I purchased my home six years ago. The patio was poured (9 years ago) completely even with the wood siding, no space between the patio and the siding. All the trim (10..2 x 2's and 3.. 4 x 2's) is completed rotted where they have touched the patio. Several places in the siding have rotted to the point that I can poke my finger through the siding. There is no space between the patio and concrete. I attempted to caulk three years ago, but that was ineffective. I have contractors coming to look at both the siding and the patio. (The patio has sunk and slopes toward the house in a small 2 feet section). Do I need to make sure the patio is fixed to allow a space between the concrete and the siding? Should I pour a new patio? What should I ask the contractors?

Thanks