Do not forget firearms security when you are building. I built a small walk-in vault in my home. I purchased a used fire vault door for $1500 and the contractor charged me an extra $1000 to add the two walls and roof to my vault room. I wound up with a 4'X8' vault with a 36"X80" combination lock fire door. I wish now I would have gone 6'X20' but I am still way a head of the game. I did get the chance to examine the same brand and style door I have that had burned. The structure was a total loss, but the interior of the vault suffered only very minor smoke damage. Papers on the counter were still in good shape. It is a rather pricey addition to a new home, but it is almost impossible to add after initial construction.