Most roof shingles consist of asphalt. Metal roofing also exists, but is typically sold in sheets or panels, and not in shingles. In the world of asphalt shingles, two varieties dominate the market: organic and fiberglass. To confuse matters even further, organic shingles come in both standard and laminated varieties. The laminated organic shingles are heavier and more durable, containing a dual-layer design, and are therefore preferable to standard organic shingles.
Laminated organic shingles offer excellent wind resistance, high tear strength and strong protection against highly frigid weather conditions. If you live in an extremely cold climate, you may want to consider the climate, and not the roof slope, as your primary deciding factor. Both organic and fiberglass shingles can suit a standard slope roof, but they do not offer the same level of resistance to cold and inclement weather conditions. Also, some organic shingles naturally contain layers of copper or tin, which reduces the problems of moss and algae that love to grow on sloped roofs.
Though organic shingles have the advantage when it comes to temperature, fiberglass shingles have the advantage when it comes to rain. Fiberglass shingles are more resistant to rain and moisture as well as fire. If you live in an especially wet region or in an extremely dry climate subject to brush fires, fiberglass is the preferable choice. Make sure to have these shingles professionally installed, however. Fiberglass shingles may crack in cold weather if not properly installed.
Whatever type of shingle you choose, do your homework first. Make sure that the shingles are in full compliance with the American Society for Testing and Materials standards. As long as the shingles are in full compliance, they should fully suit and protect your standard slope roof.