Steep Slope Roofing Systems
There are a number of things to consider when selecting a new roof system. Of course, cost and durability head the list, but aesthetics and architectural style are important too. The following roofing products commonly are used for steep-slope structures.
Asphalt shingles- possess an overwhelming share of the U.S. steep-slope roofing market. Asphalt shingles are reinforced with fiberglass materials.
Fiberglass shingles consist of a fiberglass mat, top-and-bottom layers of asphalt, and mineral granules.
Asphalt shingles fire resistances, like most other roofing materials, are categorized by Class A, B or C. Class A signifies the most fire-resistant; Classes B and C denote less fire resistance. Generally, most fiberglass shingles have Class A fire ratings, and most organic shingles have Class C ratings. A shingle’s reinforcement has little effect on its appearance. Fiberglass products are available in laminated (architectural) grades that offer a textured appearance. Zinc or copper-coated ceramic granules also can be applied to fiberglass products to protect against algae attack, a common problem in South Florida. Asphalt shingles also are available in a variety of colors.
Regardless of their reinforcing type and appearance, asphalt shingles’ physical characteristics vary significantly. When installing asphalt shingles, NRCA recommends use of shingles that comply with American Society for Testing and Materials (ASTM) standards. ASTM D 3462 for fiberglass shingles. These standards govern the composition and physical properties of asphalt shingles; not all asphalt shingles on the market comply with these standards. If a shingle product complies with one of these standards, it is typically noted in the manufacturer’s product literature and on the package wrapper.
Tile Roofing System- Clay or concrete tile is a durable roofing material. Mission and Spanish-style round-topped tiles are used widely in South Florida, and flat styles also are available to create French and English looks. Tile is available in a variety of colors and finishes. Tile is heavy. If you are replacing another type of roof system with tile, you will need to verify that the structure can support the load.
Metal Roofing System- Metal, primarily thought of as a low-slope roofing material, has been found to be a roofing alternative for home and building owners with steep-slope roofs. There are two types of metal roofing products: panels and shingles. Numerous metal panel shapes and configurations exist. Metal shingles typically are intended to simulate traditional roof coverings, such as wood shakes, shingles and tile. Apart from metal roofing’s longevity, metal shingles are relatively lightweight, have a greater resistance to adverse weather and can be aesthetically pleasing. Some have Class A fire ratings.
Synthetic roofing products simulate various traditional roof coverings, such as slate and wood shingles and shakes. However, they do not necessarily have the same properties.
Before making a buying decision, NRCA recommends that you look at full-size samples of a proposed product, as well as manufacturers’ brochures. It also is a good idea to visit a building that is roofed with a particular product.
Steep Slope Roofing System Breakdown
All steep-slope roof systems (i.e. roofs with slopes of 25 percent or more) have five basic components:
- Roof covering: shingles, tile, slate or metal and underlayment that protect the sheathing from weather.
- Sheathing: boards or sheet material that are fastened to roof rafters to cover a house or building.
- Roof structure: rafters and trusses constructed to support the sheathing.
- Flashing: sheet metal or other material installed into a roof system’s various joints and valleys to prevent water seepage.
- Drainage: a roof system’s design features, such as shape, slope and layout that affect its ability to shed water.
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