Hokay..... I'ma' go out on a limb here with some stuff. Going to throw some random brain-fodder out. Some things to consider maybe?
I've actually lived with underground vaults in my home for 25 yrs as well as having friends with them and building more than 20 others ranging from 8X8 to 20'X60' and several with shooting lanes extending further underground.... and some with living quarters for surviving Armapocalyptigeddon with 2yr nuclear winter.
Some a' ya's gonna' hafta' remember THESE ARE MY OPINIONS!!! These are things I've actually experienced. They may be completely irrelevant to others....and
I'm not arguing with anybody.
GUN vaults.....
-#1, "waterproofing" the walls does little or nothing to prevent rust. Nor does heat. In My World.....
AlWorld...... I want the "relative humidity" to be kept under 35%. Cuz it works.
Note the word "relative."
And the room's gonna' breathe. The same way water gets into your Obamafuel while it's in the gas tank, water will breathe into your vault. I recently burnt up my twohunner'dollar dehumidifier unit and am currently running a new one, a new brand, into the bucket on the unit because I was without for 3wks....and I'm a curious guy....... I've pulled 3 QUARTS of water in a couple days..... Once it stabilizes I'll hook up the hose and stuff it out thru the hole into my footing perimeter drain system...... IMO it's imperative the room have an electric dehumidifier unit. One with a permanent drain.
#2, Poured concrete or block? Once you've established just WHAT your goals are (gun storage? Ammo/powder? Hideout shelter? Food/valuables? etc etc) you will decide on a door. One thing you'll consider is
width of this door. Doors weigh anything from a couple hunnerd pounds to tons. Mine, in my home weighs 1700lb. An acquaintance of mine bought a salvage bank door for cheap, basically hauling, and it was heavy..... REAL heavy. We've moved, hung and adjusted a lot of doors and believe me a 1000lb door is no joke. My point concerns the wall itself and how the door is fastened at the hinge side. And just how much pressure is on that upper hinge when the door swings open. In simple terms, I wouldn't hang my own door into a typical homeowner-filled CMU wall. Nor even a poured cell, grout-filled w/pre-mix CMU wall unless the header was side-reinforced.... just sayin'
#3, Air management. HERE'S where the money goes. Especially if you consider the room to be a "Safe Room" for the helpless ones when the boogeyman cometh. I say, "forget the boogeyman and make a gun-storage room." Unless you're rich. Bottom line, for gun storage YOU DON'T WANT AIR INGRESS!!!!! We just did a vault in a "Homes For Heroes" project and I was PISSED! The designer (backed by architect/engineer/etc etc, basically every JAFO on site) drew it up with the home HVAC system plumbed into the room. Basically wrecked the room..... heat and AIR are required for sustained combustion and damage. seal out the air and fire becomes a non-issue.....
But I digress, lest this become a funding diatribe
Point is, it is my considered opinion that for GUN STORAGE and including paper valuables (records/recpts/certificates) and photo/digital you want air ingress kept at minimum. I pour my wiring conduits in, pour my door-frame and drill out any drainage holes. AND..... because I'm weird, I personally drill some extra holes leading into a box of screen with a piece of scrap pipe running out. And plug the holes.... so if the house is burning down and I'm IN THE ROOM, or if the zombies come and WE DO hide in the room, I can pull the plugs and breathe (suck air) thru these tubes but without compromising the integrity of the room.
#4, drainage..... drainage drainage drainage. And protection from flooding. The room MUST be isolated from water table, flood table, storm water etc and never believe that "water-proofing" will stop water. Shucks, (from actual experience) if you DO SUCCEED with your boat it may well pop right out of the ground like a coffin some day....... just make sure the floor of the vault is ABOVE any water by surrounding the footers with free-draining material/pipes etc. PERIOD!!
Whewww, sorry.... I get carried away.
I'll stop now but offer these points of thought/discussion;
GUN vaults with AMMUNITION STORAGE..... self-contained oxidizers, HEAT is the problem...
HIDEOUT rooms or "Safe Rooms"....... Time frame?? Air?? Air-tight gun storage inside??
FOOD/FAMILY HEIRLOOM storage......dry-dry-dry. My family dries and keeps wedding/bridal flowers hanging in the rafters....
LONG TERM underground shelters..... for instance toilet facilities and gravity-flow water or hand pump (seriously)