A modular enclosure, such as a shed, may include sidewalls and a roof. The roof, for example, may include first and second roof panels that are separated by a seam. The roof may also include a truss that is sized and configured to support the roof panels. The truss may include a channel that allows any moisture entering the shed from between the roof panels to be removed from the shed. In particular, a portion of the first roof panel and a portion of the second roof panel may be at least partially disposed within the channel. Advantageously, the truss may be constructed from metal, which may allow a strong and sturdy shed to be constructed, and the roof panels may be constructed from blow-molded plastic, which may allow a lightweight and generally weather resistant shed to be produced.