Hot and cold risers making a closet musty
I posted this on the plumbing forum but got no response.
We live in a 1927 Bklyn co-op apartment. The bathroom risers have shutoff's in the adjacent closet. When we moved in, I could feel the warm and cold parts of the closet wall. We had our contractor re-do the wall a couple of inches away from the pipes for air circulation. The floors / ceilings are concrete slab. The 2-2 1/2" risers are most likely hot- brass and cold- copper. The door frames are steel and the one leading to the bathroom is rusting from the inside out. The tile is turning rust color as well. The closet in question is starting to smell musty and one bottom corner of the wall is deteriorating so I put in two buckets of damp rid.
When we remedy this, what is the right way to do it? The building manager says we should insulate the cold riser. Is this enough? I'd would like to repair the rusting door frame as well. What should I use for the new wall material? Cement board or green board? I don't want to have a mold/or any issue in the future.