Decking Stair StringProduct Information A Treated Decking Stair String is a sturdy, pressure treated wooden component used as the framework for deck stairs. It provides structural support for the stair treads and risers, ensuring a secure and stable staircase. Made from high quality, treated wood, the stair string is designed to resist rot, decay, and insect damage, ensuring long lasting durability and minimal maintenance. This treated wood is ideal for outdoor use,