Fortis is extruded from an aluminum alloy (6005-T5 aluminum) that will not rust. However, as with other decking materials including wood, composite, or even concrete, steel products that come in contact with your deck surface can rust and even stain Fortis. Do not store metal objects that could rust and stain your deck on Fortis. Avoid metal working on Fortis, as well. When installing iron railings, protect your deck surface with a non-plastic drop cloth to prevent grinding dust and weld splatter from settling on the surface of your deck.