Steep-slope roofing includes watershedding types of roof coverings, installed on slopes exceeding 3:12 (14 degrees). There are six generic classifications of steep-slope roof coverings.

  1. Asphalt shingles
  2. Clay and concrete tile
  3. Metal roof systems for steep-slope applications
  4. Slate
  5. Wood shakes and wood shingles
  6. Synthetic

Steep-slope roof systems are typically composed of individual pieces or components installed in shingle fashion. Steep-slope roof assemblies usually consist of the following primary parts:

  • Roof deck: A roof deck is the structural substrate. It is most common a wood-based material such as plywood or oriented strand board (OSB).
  • Underlayment: The underlayment provides temporary protection until a roof covering is installed and provides a secondary weatherproofing barrier. Underlayment may also be referred to as "felt" or "paper".
  • Roof covering: The roof covering is the external watershedding material.