I replaced my shingle roof 8 yrs. ago with a steel roof, I laid down felt as a moisture barrier. now I noticed I get frost under the plywood in cold weather and am getting a mold problem. is this a problem with the moisture barrier under my steel or to much moisture in the attic. any ideas on cure for this problem. if it matters I have 12 inches of fiberglass insulation in my ceiling.
Your ventilation system is not working like it’s supposed to.
You have a hip roof or is there any gables?
If you have any gables
A good solution would be an attic gable wall fan.
Frost can’t form without moisture in the air. Attic ventilation problem.