Drainage under a deck can be performed by a structure that includes hanging components and corrugated panels. For example, a hanging component can have connected first and second portions, with the first portion being connected to hang from one of the joists and extending downward to where it connects to the second portion, which is below the joist. The second portion can be connected to support of at least one of the panels from above. The upper surfaces of panels are sloped so that drainage occurs from a high part to a low part. The direction of slope and the direction of corrugations are not perpendicular, and can be approximately the same. The hanging components can, for example, be L-shaped brackets, U-shaped, or inverted T-shaped, and can be integrally formed by extrusion of plastic or can be metal. The panels can be corrugated plastic or metal sheets.