Today there's a wide choice of roofing materials available. While all are durable, each has advantages and trade-offs. We'll take a close look at two popular choices:
Asphalt shingles and cementatious roof tiles.
Asphalt shingles are the most common roofing material, and they come in two broad categories--organic based and fiberglass. Organic base means the shingles are made of a cellulose mat saturated with asphalt and covered with mineral granules. Fiberglass shingles have a mat of woven glass fiber saturated with asphalt and covered with mineral granules.
Organic shingles have a Class C fire rating; fiberglass shingles have a Class A rating.
An important difference between the two types of shingles is that organic types are more flexible in cold weather than fiberglass types. A good deal of controversy surrounds the installation of fiberglass shingles in cold climates. Some roofers refuse to install them, while others don't install them in cold weather. These roofers cite the shingles' premature failure due to their stiffness. Manufacturers, however, say a properly installed fiberglass shingle is as good as any.
The two most common types of asphalt shingle are three-tab (also called a strip shingle) and architectural (also called a laminate shingle).
A three-tab shingle is a rectangular mat with two slots cut in its front edge. The slots provide stress relief as the shingle expands and contracts with the weather.
An architectural shingle has a heavy base mat and another mat or sections of mat applied on top of it. Aside from making the shingle heavier and more durable, this construction gives the roof shadow lines and character like a tile or wooden roof.
A standard three-tab shingle can be organic or fiberglass based. Most architectural shingles have a fiberglass mat, although some are organic.
Finally, there are regional and specialized forms of asphalt roofing, such as a highly wind resistant shingle called a T-lock. This is a slotted T-shaped shingle that locks to the shingle below and to the shingle above.
Cementatious roof tiles offer traditional looks combined with the benefit of modern materials. These products are made from cellulose fiber-reinforced portland cement or concrete. They are available in red, black, white, green and gray, and they can be molded to look like wooden shingles, barrel-shaped tiles or slate.
The strong suit of cementatious roofing tiles is their durability. Because they are a masonry material, they resist weathering, insects and fire.
Their nearly impenetrable surface also resists the formation of fungus, and because they are heavy, they resist wind uplift.