Roofing systems come in a variety of forms, from shingles and tile to steel and asphalt. In some cases, culture influences the type of roofing system, such as tile use in areas with ties to Spanish culture. In areas with extreme weather conditions, such as high winds, steel roofing may supersede the more fragile shingle. In all cases though, the roofing system plays a critical role in maintaining the integrity of the home's envelope (temperature, moisture, and air pressure control).
Shingles, according to HandyAmerican, represent the most frequently employed type of roofing system in the country. Shingles start out as a thin fiberglass sheet or paper. The fiberglass or paper sheets undergo a soaking process in asphalt and have mineral granules applied to them. HandyAmerican reports that shingles may have half the life expectancy of other roofing systems, a problem offset by lower cost and ease of installation. Wood shingles represent an alternative to asphalt shingles, but regulations, due to fire concern, limit or forbid their use in many areas.
Metal roofing comes in several varieties including, according to Consumer Reports, steel, copper, and aluminum. One major advantage of metal roofing is that it will not burn. Depending on the variety, however, metal roofing costs more than other types of roofing systems, copper in particular, and may produce more noise in rainy conditions.
A roofing system with a long history, according to HandyAmerican, clay tiles date back as far as the Babylonian Empire. Clay tile production involves molding and then firing (baking) clay. The shape of the mold determines the final profile of the tile (curved, flat, s shaped). Tiles may also undergo a glazing process to alter color or provide sheen. Clay tiles find prominent use in the American Southwest. While more expensive than most roofing systems, clay tiles can last for the life of the home, according to HandyAmerican.
Concrete tiles offer the same benefits of clay tile, but at a lower price. Made through an extrusion process, according to the National Roofing Contractors Association (NRCA), the tiles undergo a curing (set and harden) process to achieve strength. Available in the same styles or profiles as clay tiles, concrete tiles may also resemble slate and wooden shakes. The addition of oxides provide the tiles with color and surface treatments can provide textures.
More common on flat roofs, built-up roofs employ alternating layers of roofing felt and tar. According to the NRCA, the final layer of material to finish the roof can include materials such as gravel, mineral granules, and even glass-fiber. While one of the most inexpensive flat roofing methods, damage to the tar from ultraviolet light (sunlight) will require roof replacement sooner than more expensive alternatives.
Uncommon on typical homes and quite expensive, slate remains popular for government and high-end homes, according to HandyAmerican. Installation should only be undertaken by a professional crew with experience handling slate. Like clay tiles, slate can also last for the lifetime of a home.