Underdecking systems are made up of panels and gutters that are placed underneath the deck to keep the space dry. It solves the issues of drainage and stability by using gutters, downspouts, ceiling panels and support braces. This enables you to create a more appealing or more usable under-deck space. The benefits of underdecking include protection from moisture damage, aesthetic appeal, and increased usability of second-story patio space. Inside Out Underdecking by Quality Edge provides panels, a system carrier, g channel, and side caps to meet your underdecking needs.