Roof System Components

All steep-slope roof systems (i.e., roofs with slopes of 25% or more) have five basic components:
Roof System Components

  1. Roof covering: shingles, tile, slate or metal and underlayment that protect the sheathing from weather.
  2. Sheathing: boards or sheet material that are fastened to roof rafters to cover a house or building.
  3. Roof structure: rafters and trusses constructed to support the sheathing.
  4. Flashing: sheet metal or other material installed into a roof system’s various joints and valleys to prevent weather seepage.
  5. Drainage: a roof system’s design features, such as shape, slope and layout that affect its ability to shed water.