Exterior staircases used for Utilihab decks and walkways are largely the same as the basic stairs employed in interior applications with side or underside stringers supporting open steps and attaching to the perimeter profiles of the deck/walkway structure. Exterior use steps will usually be made from standard aluminum stair/mezzanine planking or polywood, stone, or light concrete planks bolted to supporting underside profiles or riser blocks. Walkways can integrate side supporting stringer beams into the walkways side beams, creating a continuous look. Decks can support very wide stairs between deck terrace levels using multiple underside stringers supporting very long step planks.