I have been asked to finish a friends basement, but have a unique (to me) situation with part of the basement ceiling. There is a walkout from the basement at the front of the house and the ceiling in this area is actually the poured concrete front porch. So the ceiling joists that are tied to the rest of the basement have concrete above them. I am worried about insulating this part of the ceiling and having moisture problems coming through the concrete porch. Any ideas?
Is this a wood frame supporting metal deck sheets with the concrete poured over the metal decking? Your concern on moisture is certainly valid. If you can ventilate the space between the insulation and the decking you may want to consider that.
Hard to say without some detail but venting will be extremely difficult and even more so to achieve two way (directional) venting. I would consider spray foam insulation for the entire joist cavity and not venting the space. Foam must be covered with drywall. Attention is also required for the slab wall junction at the first floor level to prevent water penetration.. Just my thoughts...