Asphalt shingles are currently the most popular type of residential roof material for a variety of reasons. They are relatively inexpensive, starting at around $2.00 per square foot installed and go up from there. Things that determine cost are geographical location, slope of the roof, height of the building, ease of access to the premises, complexity of the project, the particular type of shingle and numerous other factors. They come in a variety of colors and styles, are fairly durable (some have been tested and have achieved a class IV hail rating – the highest available!), and can be easily repaired and maintained.
Asphalt shingles come in two basic types: glass fiber (a.k.a. fiber glass) and organic. Organic shingles consist of an organic felt material which is generally paper saturated with asphalt to make it waterproof. A top coating of adhesive asphalt is then applied and the ceramic granules are then embedded. Organic shingles contain around 40% more asphalt per square (100 sq. ft.) than their glass fiber counterpart which makes them weigh more and gives them excellent durability and blow-off resistance.
Glass fiber shingles have a glass fiber reinforcing mat manufactured to the shape of the shingle. This mat is then coated with asphalt which contains mineral fillers. The glass fiber mat is not waterproof by itself. Its purpose is for reinforcement. What makes the glass fiber shingle waterproof is the asphalt. However, the asphalt itself will not stick to the mat. For this reason, “fillers” are used. The fillers in the asphalt cling to the glass fibers in the mat. The asphalt then encapsulates the glass fibers, fills all of the holes and voids in the mat rendering it waterproof. After this cools a bit, an adhesive asphalt is used to cover the mat and the ceramic granules are then embedded.
The ceramic granules are there for two reasons. The primary reason is to protect the shingles from the sun. The sun’s UV rays are very damaging to asphalt and cause it to deteriorate prematurely. This is one of the same reasons that gravel is used on built-up roofs. The second , more obvious reason for the granules is aesthetics. Asphalt shingles are available in a wide variety of colors to match almost any facade or landscape.
So which type is better? By far, the more popular shingles are the glass fiber ones. This may be attributed to the fact that they are cheaper and easier to manufacture than organic shingles . This makes these shingles more cost effective to the homeowner and easier to work with for the roofing contractors.
The lifespan of asphalt shingles depends highly upon the environment. Shingles in cooler climates such as the northern United States seem to last longer than those installed in the warmer climates. Studies have shown that the average lifespan for a 20 year shingle in Phoenix , Arizona is around 14 years. In Minneapolis , Minnesota , the lifespan was 19.5 years. And in Reading , Pennsylvania , the lifespan was 20.8 years. From this data it seems obvious that the hotter the environment is, the shorter the service life of the shingles.
In addition to UV rays, Thermal Shock is also very damaging to shingles. Thermal Shock is what roofing materials experience when the ambient temperature changes dramatically within a very short period of time – usually 24 hours. For example, in Eureka , California , the temperatures during a summer day can often reach 100 degrees and at night, they’ll often drop below 50, sometimes as low as 40. Roofing materials are unable to expand and contract to accommodate such a dramatic temperature change in such a short period of time so cracks and splits in the materials start occurring. Water can then enter the materials and damage them further in two ways. The continuous presence of water will permit algae and fungus to grow on asphalt materials. The freeze-thaw cycle that results from the dramatic temperature change will also deteriorate shingles. In the cold months, water will get into the cracks and then freeze at night. Water expands as it freezes so the more this occurs, the bigger the cracks or splits become. This is why most roofing contractors and consultants are such big advocates of sloped roofs. The better the roof sheds water, the less problems it will usually experience. Still another factor affecting asphalt shingle roofs is attic ventilation. Proper roof ventilation has been known to extend the service life of a roof.
Shingle manufacturers provide product warranties against manufacturing defects ranging from twenty (20) to fifty (50) years and beyond. The warranties will cover defects such as thermal splitting, some cases of granule loss, cupping, and curling. It is very important that you ask for and receive a copy of the manufacturer’s written material warranty before making a decision on whose material you’d like to use. Warranties are generally for materials only. Labor is rarely included so if your roof materials fail, you’ll have to pay a roofer to install the new shingles. Warranties rarely, if ever, cover what are known as “incidental and consequential” damages resulting from material failure. “Incidental and consequential” damages are those that occur to the interior of the building. If anything on the inside of the building gets damaged, you or your insurance company will have to pay for it. Warranties are also commonly prorated and non-transferable. This means that if you have twenty year shingles and they fail after ten years, you’ll be reimbursed for half the cost of the materials. Non-transferable means that if you sell your house, the warranty will be voided. Some shingle manufacturers are offering NDL (No Dollar Limit) warranties for added costs of around 4.5 cents to 6.5 cents per square foot. These warranties may or may not cover all damages and labor costs. Shingle manufacturers will not warrant their products against “Acts of God or Nature” such as hurricanes, hail storms, severe winds usually in excess of 50 mph, tornadoes, earthquakes, etc. In addition, shingle manufacturers will not honor their material warranty if the products are improperly installed. If there is improper roof ventilation, equipment installation or structural changes after roof completion, or heavy foot traffic on or over the roof, the warrany will be void. For specific warranty information, be sure to ask your roofing contractor to provide a sample warranty of the materials that he installs.
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