Steep-slope roofs
There are several types of roofing systems typically installed on steep-roofing projects. Existing low-slope roofs can be replaced or retrofited.

Shingle/Slate/Tile

Shingle: A small unit of prepared roofing designed for installation with similar units in overlapping rows or courses on inclines normally exceeding 3:12 slope (14°)
Slate: A hard, brittle metamorphic rock consisting mainly of clay minerals, used extensively as dimensional stone for steep roofing and in granular form as surfacing on some other roofing materials.
Terra cotta: Low-fired clay, either glazed or unglazed.

Metal

Metal: Any of various opaque, fusible, ductile and typically lustrous substances that are good conductors of electricity and heat.
There are several types of metal roof systems.
Architectural Standing seam: in metal roofing, a type of seam between adjacent sheets of material made by turning up the edges of two adjacent metal panels and then folding or interlocking them in a variety of ways.
Copper: a natural weathering metal used in metal roofing or flashing; typically used in 16 ounce per square foot (0.56 mm) and 20 ounce per square foot (0.69 mm) thicknesses.
Aluminum: a nonrusting, malleable metal sometimes used for metal roofing and flashing.
Galvanized steel: steel coated with zinc for corrosion resistance.
Steel: a malleable alloy of iron and carbon produced by melting and refining pig iron and/or scrap steel; graded according to the carbon content (in a range from 0.02 to 1.7%); other elements, such as manganese and silicon, may be included to provide special properties.