As you may know, there are two basic types of asphalt shingles. Each consists of a core material that is coated with asphalt, and then covered with granules. This core, or base material may be either fiber glass mat or organic felt. Shingles made of each type of base material possess specific characteristics and attributes that recommend them for particular situations. Fiber glass shingles carry a Class A fire resistance rating from Underwriters Laboratories (UL), the highest fire rating available. Thus, fiber glass shingles are the best protection against the spread of flame on a roof. Fiber glass shingles are so called because they are built on a core, or mat, of fiber glass reinforcement. Asphalt coating is applied directly to this mat, and protective, colored granules are embedded into the coating. Since the mat does not need to be saturated with asphalt, fiber glass shingles are lighter in weight than organic shingles and are more resistant to heat and humidity. Perhaps the most important factor that influences the quality of fiber glass shingle performance is the quality of the mat used in the construction of the shingle. Throughout the roofing industry, the quality of fiber glass mats varies widely. The American Society for Testing and Materials (ASTM) has established a standard of performance for fiber glass shingles, ASTM D3462, "Standard Specification for Fiber Glass Asphalt Shingles." This test measures the force, in grams, required to tear a shingle in a specialized measuring device known as the "Elmendorf Tear Tester." As measured this way, the minimum tear strength required by ASTM is 1700 grams.

Organic shingles have a thick, organic felt base reinforcement. In the manufacturing process, the felt is saturated with a soft, flexible asphalt. It is then completely coated on both sides with tougher coating asphalt and then covered with granules. The result is a tough, durable shingle with excellent durability in extreme cold weather and good performance characteristics in extreme heat. Organic shingles carry a Class C fire resistance rating from Underwriters Laboratories.

Characteristics that equate to high or low quality in an organic base shingle include tear strength, flexibility and cold weather handling. ASTM does not provide a standard test for tear strength in organic shingles. Nevertheless, a good organic shingle with tear strength well over 2,000 grams typically will demonstrate excellent cold weather, high wind performance. One measure of the flexibility of a shingle is an "Uplift Flexibility" test, in which the shingle is bent in the same direction as it would be by the action of the wind. The load required to bend the shingle through a range of angles up to 90 degrees is recorded and used to calculate the flexibility index expressed as a percentage. A good organic shingle will have a flexibility index of 50% or greater. A high value is one indication of a shingle's toughness (especially at low temperature), its resistance to blow-off and damage in handling, and its ability to resist cracking as it ages in service on the roof.

In the end, it must be said that either fiber glass or organic shingles can be manufactured to withstand extreme performance standards. Clearly, fiber glass-based shingles have the edge in warm weather areas. Both types of shingles can be made to perform excellently in cold weather. But fiber glass shingles must be manufactured to the most stringent performance standards to perform reliably in the far north. Not all fiber glass shingles meet these standards. So, it is a case of buyer beware.

Both fiber glass and organic-based shingles are asphalt shingles although because organic shingles were developed before fiber glass shingles, the term "asphalt shingles" is often used to reference organic shingles only.

The same thing as an asphalt shingle; basically, any shingle constructed of a base (fiber glass or organic), asphalt and granules.

Since it is probable that defects, should any be present, will appear during the first three to five years of the life of the roof, a longer warranty does not necessarily mean as much as it would appear to.

In certain moist areas, algae can grow on shingles. Although the algae has no proven effect on shingle life, it does stain or discolor the shingle. Commonly (and usually incorrectly) called fungus, this algae staining can be unattractive. The algae-containing stains can be dramatically reduced by the use of special copper granules. Copper-containing granules are mixed with colored granules during the manufacturing process. The effect is to produce an environmentally safe cuprous oxide wash which is dispersed by rain or other moisture. The wash inhibits growth of algae and the resulting stains.

Moss is not fungus. Moss is the green spongy stuff that grows on the north side of trees and on the ground in shaded, damp areas. And, in some areas it also grows on roof shingles.

Mosses reproduce via airborne spores. If a roof is covered with moist organic matter or soil, and if there are minerals and fixed nitrogen present in the dirt on the roof, mosses can grow from the spores that are carried there. It is obvious that if there is no dirt on the shingles, moss cannot take root. But, even when dirt is present, it is possible that the copper used in most fungus-resistant shingles today will prevent moss development in its early stages.

The typical ice dam is a buildup of ice that forms near the eaves or gutters as the result of interior heat escaping into the attic and through the roof decking. The heat melts the snow and ice on the upper areas of the roof resulting in melt water. This melted water runs to cold, lower areas or eaves and, depending on  conditions, can refreeze. Leaks occur if the water finds its way under the shingles or behind fascias or cornices.

No, metal roofs will not attract lightning. Lightning is typically attracted to the highest point in an area, not exclusively metal objects. If lighting should strike a metal roof it may be safer than traditional roofing products, since a metal roof will help conduct and dissipate the electrical charge of lightning. Also, a metal roof is non-combustible so it will not burn if struck by lightning.

Metal roofs are very strong and durable. In most cases, metal roofing is not damaged by hail. It will not crack, or break when struck by hail, as would other roofing materials. Also, formed profiles that look like shake, tile, slate, or asphalt will hide minor cosmetic damages that may result from severe hail storms.

The fire safety aspect of metal roofing is a definite benefit. In fire prone areas of the country or where houses are built close together, fires are often spread by sparks and embers landing on the roof from a neighbor's house, Steel is non-combustible; therefore, it does not burn or support combustion, A metal roof may even lower your homeowners insurance premiums.

Pre-painted metal roofs will not crack, shrink or erode and are a long lasting alternative to conventional roofing materials. With a wide color selection, attractive life cycle cost, and minimal maintenance, you can look forward to a truly dependable product for 50 years or more. Metal roofing is most cases will last the lifetime of the house.

The myth of rain being noisy on a metal roof is not evident if insulation is used and the roof is properly installed. Roof noise over a living room at night, with no radio or television on, is less than 30 decibels (the same as asphalt, wood, or tile).

No matter how many layers of composition or large amounts of tar you put on a low pitched roof the leaks keep coming back every few years. A standing seam, metal panel roof system is ideal for low pitched roofs (some metal roof solutions are able to be used on 1/4 : 12 pitches), providing you with 30-50 years of worry free roof cover.