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.
- Asphalt shingles
- Clay and concrete tile
- Metal roof systems for steep-slope applications
- Wood shakes and wood shingles
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.