Expert: Bruce E. Johnson - 12/12/2008

Question
Hi, I have an area underneath my front porch accesable from my basement.  It is an enclosed area with a concrete floor, and 8x16 block for walls.  I have a steel door separating it from my basement.  The ceiling is corregated steel of which the concrete pad of the front porch was poured on.  The room is completely underground, and is not heated (except what may come form the basement when the steel door is open.)  I notice that water droplets/condensation forms on the corregated steel panels on the ceiling.  I want to frame the ceiling in an put fiberglass insulation.  My question is  do I need to put a sheet of plastic on the steel to act as a vapor barrier, or can I used faced owens corning fiberglass insulation, with the paper side facing the floor.  Thanks, Bob

Answer
Hi Bob, you need a couple of things.  If you are going to use this as a fruit cellar then you should read this article and others like it. You actually need humidity in a room like this to keep the fruit hydrated.  Why you want to frame this ceiling in and insulate it you don't say.  

http://www.floydcountyinview.com/rcbasics.html