Hello everyone, I was hoping to get some advice from everyone. Last year I built a new house. In the basement I had a "vault" room poured under the front porch. The porch is covered and is a cement slab and the vault is directly under it. The vault walls are all underground except for the wall that is in the basement. I installed a vault door in the basement. Inside the vault I have built racks for all of my long guns and I have pegboard on the walls for all of my pistols. I have a 2nd safe inside for all of my NFA items and some other misc items. There is electric inside and I have a dehumidifier running to keep it at 65% humidity. I was in the vault last night and I noticed mold on the stocks/slings of a few rifles. Not all of them, just a few. I took a closer look around and there is mold started to grow on one of the walls. I immediately mixed a 50-50 water/vinegar solution and sprayed to wall. I wiped down the effected rifles with Rem Oil as well. So what the heck am I doing wrong? Any tips on how to prevent this? There doesn't appear to be mold anywhere else in the basement but I have to check more in depth when I get home. Thanks everyone!