Exterior Metal Spiral Staircase The exterior metal spiral staircase is including staircase steps, balusters, handrails as well as accessories for installing. It can be installed both indoor and outdoor, It's easy to install. just make sure the center post is firmly connected with the ground, then install the steps and balusters piece by piece, the last step is to weld the handrails with the balusters. then the whole staircase can be done. So whether your application is internal or external and you favour the traditional, just take a look at these well-made individually cast spiral staircases from ShengHongYuan. Advantage A wide variety of metal options are available to you, such as cooked iron, galvanized iron, aluminum, bronze, and stainless steel. A wide range of colors and finish types are available. Provide you with high quality customized exterior iron railings with long life and low maintenance.