Currently, my 6'x10' back porch sits 3' above the ground and shares it's foundation on two sides with the house, a third side is poured and the fourth totally open. The porch floor is slats (like a deck) and has a roof over half of it, but the sides and staris are open. I plan to completely remove the porch, steps, roof, etc, build a new fourth side for the foundation and build a new room from there. My goal is to enclose the porch, making it into and entryway, or coatroom, giving us a place to take off our shoes and coats before stepping into the kitchen. My concern is that this new finished part of the house will be built over dirt, and under it will not be accessable fom the basement. The floor will be insulated, but the room not heated, and it will have a decent door separating it from the kitchen. I'm guessing moisture will be a issue from the bare dirt under the floor and I want to prevent any problems this may bring. My first thoughts are to lay down plastic over the dirt and install a vent,or even a small access door, on my fourth foundation wall for ventillation. Should I even enclose this porch over dirt? What can I do to prevent damage from moisture? Any other thoughts?