Steel, one of the strongest building materials around, is the best material for storm shelters in today’s unpredictable and extreme weather events. This is why Survive-a-Storm Shelters uses 10 gauge steel for all of its residential units and 1/4″ steel plate for its community safe rooms. Why do we believe steel storm shelters are the best choice? Below are just a couple of quick reasons: Steel isn’t porous, which means moisture in the air or soil surrounding it cannot penetrate its walls. This is important, because a porous material, like concrete for instance, will hold moisture…which expands when it’s cold and retracts when it’s warm. This causes cracking and crumbling in the concrete. A crumbling concrete structure is not very safe against high winds and flying debris. In a steel storm shelter, however, especially one powder-coated or covered in coal tar epoxy (methods which deter rusting), there is none of the expanding and contracting. The steel remains intact, no matter what.