I have a raised ranch.  At the back of the house, you can walk out of the lower level onto a patio.  Above the patio there is a three-season room.  It sits on 2×12 joists that are attached to a ledger board at one end and sit on a beam near the other end.  There are several electrical, telephone and cable/internet wires run along the joists and through holes in them.  I would like to insullate, in order to keep the three-season room warmer, and cover the joists to create a ceiling over the patio. 

Also, a small area on the underside of the three-season room’s plywood floor has sometimes gotten damp near one of the room’s corners.  I think I have fixed the problem, but it is an intermittant problem so only time will tell.

1.  What are the best options for insulating the three-season room floor, considering the wires and the, hopefully corrected, intermittent water problem?

2. What are the best options for closing in the joists to create a ceiling over the patio?  I like the traditional look of narrow boards, but it would also be nice to be able to remove section of the “ceiling” to update wiring or to check on the intermittent water problem.

I would appreciate any suggestions as to materials or methods to use.