How a Roof Works: Layers, Parts and Water Flow
Framing, deck, underlayment, flashing and covering: how the layers of a roof divide the work of keeping water out, and how rain travels from ridge to gutter.
Roof Basics
How a roof works starts with its parts: the decking, underlayment, covering, flashing, drainage and ventilation that keep water out. These guides explain the parts of a roof, its types and pitch, and how roofs are measured.