Ole Humpback
Member
I've been researching gun safes here and elsewhere and I've seen several comments that have given me pause. Quite a few people have made a statement along the lines of "I don't need to worry about how heavy the safe is, I'm going to put it in the garage/basement. The problem is, the concrete basement or garage isn't much better than a wood framed floor when it comes to supporting weight.
A typical wood framed floor in a bedroom or closet is rated for a 20psf deadload and a total load of 30psf. A concrete basement/garage is rated for a 50psf deadload/total load or a 2000lb point load over a 20"sq area. This is from the 2003 IRC and the codes have changed since then, but the load ratings haven't changed in the 2011 IRC as far as I can tell.
http://www.aacounty.org/IP/PAC/CodeRequire.cfm
The typical 20 gun fire rated RSC with a full load is running just under 1000lbs with a foot print of 644sq" (4.47SF). A wood framed floor is only capable of safely carrying 30psf total load which for a 4.47SF area is 134.4lbs. A concrete garage or basement slab would be able to carry only 223.5lbs over the same foot print. This means that for the typical home, a 20-gun fire safe is overloading the floor 7.5 times its designed loading and 4.5 times the design loading for a concrete slab. This is for something the size of a Liberty Centurion safe that most consider as safe to keep on a wood floor. An empty Centurion weighs just under 500lbs, which is already over loading even a concrete floor.
Now, I grant you all that the slab won't fail or the safe fall through to China the moment a Centurion sized safe is placed on them, but bear in mind that even a small fire safe for even 10 guns is 5 to 10 times in excess of the designed floor loading. And most of the safes I've seen mentioned as garage or basement items weigh several thousand pounds empty and weigh more than the two cars they have in the garage.
Garage slabs are thickened under the tire tracks, basement slabs are thickened where they turn down to intercept the footer. None are designed with a several ton permanent deadload in mind. A garage slab will be about 6"-8" thick Type III 3000psi concrete and have either #4 bar mats or sheets of 1.4 WWF steel reinforcing. A basement slab will be 4"-6" of the same concrete and have a wide web of #4 bar or a single layer of WWF reinforcing it.
When buying a safe, give serious consideration to the loading it will apply to your structure. Structural repairs to wood floors aren't cheap, but can be limited in cost if the engineer & contractor know what they are doing. Structural repairs to concrete slabs on the other hand aren't cheap. It starts out with mud jacking and can end up with foundation excavation & undercutting so that the damaged concrete & soils can be cut out & replaced with extra reinforcing to support the safe.
An ounce of prevention now is worth a pound of cure later.
A typical wood framed floor in a bedroom or closet is rated for a 20psf deadload and a total load of 30psf. A concrete basement/garage is rated for a 50psf deadload/total load or a 2000lb point load over a 20"sq area. This is from the 2003 IRC and the codes have changed since then, but the load ratings haven't changed in the 2011 IRC as far as I can tell.
http://www.aacounty.org/IP/PAC/CodeRequire.cfm
The typical 20 gun fire rated RSC with a full load is running just under 1000lbs with a foot print of 644sq" (4.47SF). A wood framed floor is only capable of safely carrying 30psf total load which for a 4.47SF area is 134.4lbs. A concrete garage or basement slab would be able to carry only 223.5lbs over the same foot print. This means that for the typical home, a 20-gun fire safe is overloading the floor 7.5 times its designed loading and 4.5 times the design loading for a concrete slab. This is for something the size of a Liberty Centurion safe that most consider as safe to keep on a wood floor. An empty Centurion weighs just under 500lbs, which is already over loading even a concrete floor.
Now, I grant you all that the slab won't fail or the safe fall through to China the moment a Centurion sized safe is placed on them, but bear in mind that even a small fire safe for even 10 guns is 5 to 10 times in excess of the designed floor loading. And most of the safes I've seen mentioned as garage or basement items weigh several thousand pounds empty and weigh more than the two cars they have in the garage.
Garage slabs are thickened under the tire tracks, basement slabs are thickened where they turn down to intercept the footer. None are designed with a several ton permanent deadload in mind. A garage slab will be about 6"-8" thick Type III 3000psi concrete and have either #4 bar mats or sheets of 1.4 WWF steel reinforcing. A basement slab will be 4"-6" of the same concrete and have a wide web of #4 bar or a single layer of WWF reinforcing it.
When buying a safe, give serious consideration to the loading it will apply to your structure. Structural repairs to wood floors aren't cheap, but can be limited in cost if the engineer & contractor know what they are doing. Structural repairs to concrete slabs on the other hand aren't cheap. It starts out with mud jacking and can end up with foundation excavation & undercutting so that the damaged concrete & soils can be cut out & replaced with extra reinforcing to support the safe.
An ounce of prevention now is worth a pound of cure later.