Re: Building a new house... Gun Vault..
You want all the walls off the exterior perimeter. And the room surronding your safe room gets a system. If its a safe room for you and your family, and it doesnt look like one, well that gets a system too, independent.
Simply put, one man, one drill, one sledge and this pattern:
and your wall 10" wall "isn't."
If your looking for general smash and grab protection and general fire protection for inanimate objects, well your on the right path. Crete without rebar properly placed and floated/held off from the footing to the wall and the wall to the ceiling (4-6" only!) isn;t really much. If your building this to save lives against an attack, well that is a much higher standard and much more complex. Getting one self caught behind 10" of concrete by a 14 lug door as the final gesture of some nutjob looking for an AR and a used RockChucker is a poor way to end your day.
http://vertors.com/newsletter-concrete-rebar/how-to-set-rebar-in-a-concrete-footing/
Ten grand is nothing for a good safe room, nothing.
Most folks confuse keeping things safe from fire and theft with keeping wood and steel in the right balance between overly dry and corrossion. Keeping your room at <50% humidity and at around 65 degrees is one thing before a fire, flood, etc. But set a blaze above for an hour or too and then having two trucks pump 1,000gpm for 35 minutes and you have something all together different.
Most folks simply do not have things worth the real expense of building a safe room. If all you want is to rack your guns and do some reloading, well that is one thing. No floor drains, angled exit drains at least 24" off the exiting external surface running to a dry well. The heat from a typical dehimidifier that you buy at a department store will run a sealed room up too high. Low end builders should go with one of these:
http://www.basementsystems.com/dehumidifier/sanidry-csb.html
If your external room cannot keep your safe room at least 55 degrees you will need an internal heating system for your gun room. Got 8 or ten foot ceilings on that floor? Good pour your safe room a foot higher than the rest of the floor. Be sure you have cell service indside as well. read the materials I posted above and come back if you have questions.