The Key Components of an Asphalt Shingle Roofing System

Aug 12, 2020Roofing

Asphalt shingle roofs take up as much as 80 percent of residential housing in the United States. It is because the primary roofing material itself is easy to install and offers flexibility during installation. However, the beauty, health, and performance of these roofs don’t just hinge on the covering seen from the outside.

An asphalt shingle roof has components that complement one another, making the sum of all parts greater than the whole. Having a basic understanding of them is important so you can better take care of the whole roof and communicate with your roofing contractor effectively if ever you need to have it repaired or replaced. Here’s an in-depth look at each one of them:

Asphalt Shingles

Asphalt shingles remain a popular choice of roofing material ever since they were introduced before the turn of the 20th century. Attractive and versatile, you can find them in a wide assortment of colors and styles. Some even imitate the look of wood shakes and premium slate. Also, thanks to modern innovations in manufacturing, asphalt shingles now have high fire and wind resistance ratings. What attracted homeowners, however, is the cost—they’re relatively inexpensive in terms of aesthetics and the durability they provide to the structure.

In terms of importance, asphalt shingles provide a water-shedding surface that protects your home from precipitation, wind, and other elements. Depending on your choice of color or style, the resulting outer covering for your roof creates a genuine appearance that sets your home apart from the others in your neighborhood.

There are two types of asphalt shingles mainly used in roof construction—three-tab and architectural shingles. Three-tab shingles are named as such because of the cutouts running along the bottom edge that make them look like three different shingles when installed. Architectural or laminated shingles, meanwhile, are not as thin as their three-tab counterparts, have extra asphalt, and provide better waterproofing as long as they’re installed on a steep-sloped roof.


The underlayment acts as a secondary water barrier for your roofing system, particularly for the decking or sheathing and the asphalt shingle covering. Despite being concealed between these two layers, it nevertheless helps create a better-looking and longer-lasting roof. At the same time, it protects the inside of your home from the damaging effects of moisture damage, including leaks, mold, and rot.

The following are the three types of underlayment used by roofing professionals:

  • Asphalt-Saturated Felt – Before the arrival of synthetic underlayment alternatives in the market, every roofer relied on it during roofing projects. It is composed of a flexible base material made of either cellulose or fiberglass and then saturated with asphalt for water resistance.
  • Non-Asphalt Synthetic Underlayment – It is the preferred underlayment used by many roofing contractors today, with a fiberglass addition that gives it superior tear resistance and stability.
  • Rubberized Asphalt Underlayment – It tends to be more expensive because of its high asphalt and rubber polymer content. Rubberized asphalt is waterproof, while the other two choices are water-resistant.

Ice and Water Barrier

Also known as ice and water protector or shield, it is a type of waterproof membrane developed to protect vulnerable areas of the roof such as the overhangs and valleys from the threat of wind-driven rain and ice dams. Made of rubberized asphalt, it has an adhesive back surface to ensure a firm attachment to the roof deck and form watertight end and side laps. The bitumen and polymer composition forms a watertight seal around the nail penetrations during the shingle installation.

During a thunderstorm or hurricane, strong winds can push rainwater beneath the shingles. During harsh winter, melted snow flowing down to the unheated soffit area of the roof freezes, resulting in ice dams. When this happens, water can also be forced under the shingles and into the attic. With the ice and water barrier installed together with the entire underlayment, you can minimize roof leaks and other moisture problems that may damage your home’s interior.

Starter Strip Shingles

Starter strips are long, narrow shingles that come first before the first course of the finish shingles, which are the visible parts of the roof. Manufacturers design them with a perforated line that runs horizontally so roofers can have the option to separate them depending on the installation needs. If the pros are installing larger shingles, they can leave the starter strips whole to ensure greater support. Starter strips also come with a line of adhesive to bond the shingles installed above it and create a firm seal.

These components are crucial for proper asphalt shingle roof installations because they adhere to the shingles on the roof edges and protect them from the elements. Without these, expect a gust of wind to easily cause a shingle blow-off. If there’s wind-driven rain, the lack of starter strips makes the roof even more vulnerable to water infiltration even with flashings and ice and water shields.

Hip and Ridge Cap Shingles

Hip and ridge cap shingles don’t just protect against leaks but also add finishing touches to the roof’s entire appearance. They are installed on the high-stress areas of the roof where two roof surfaces meet at an angle. They also tend to have a high-profile design, making them thicker than the rest of the shingles already installed along the roof slopes.

Standard applications require the hip and ridge caps to be installed and lapped one at a time. Some roofers, however, install them with the top about ¾-inch higher, giving the appearance of richer and thicker hip and ridge cap. The double-layered appearance matches the thick architectural shingles, resulting in a more solid and robust roofing structure.

Roof Ventilation

An asphalt shingle roofing system won’t be complete without a balanced ventilation system to keep the attic dry and cool and ensure indoor comfort year-round. During winter, a well-ventilated roof helps prevent ice dam formation and moisture accumulation inside the attic. During summer, it helps expel hot air from the attic, which then stops the premature asphalt shingle deterioration. Ideally, the air within a well-ventilated attic must not reach more than 15 degrees warmer than the outdoor air.

Roofing contractors install a system of vents to meet the recommended amount of ventilation of about a square foot per 300 square feet of attic area. This facilitates continuous airflow by bringing fresh air into the attic and taking out warm, moist air to the outside. Below are some of the most common vents found in asphalt shingle roofs:

  • Soffit Vents – These are perforated soffits that encourage air intake, ensuring better airflow for your roof in the summer and protection against ice dam buildup and moisture in the winter.
  • Baffles – These are chutes that can provide a channel for fresh air to flow from the soffit vents into your roof’s attic. Also, these components are installed to keep attic insulation off the roof decking.
  • Ridge Vents – These are installed along the roof ridge to provide better and more uniform roof ventilation than turbines and gable vents.

Of course, roofers must address other things to make sure the roof is well-ventilated. Insulation, for instance, must be of the correct R-value and installed correctly over and around attic penetrations. Proper sealing is also vital, especially if there are ductwork and other protrusions, to prevent unwanted airflow, heat, and moisture from finding their way into the attic.

If you are looking to replace your current roof with a new one, make sure to work with a reliable contractor like Home Remedy USA. As a GAF-certified local roof replacement company, we take pride in installing the GAF Lifetime Roofing System, which comprises all of the roofing components discussed above. With this combination of products, you get a roofing system that offers better weather protection, energy efficiency, and long-term value compared to regular roofs.

To learn more about the GAF Lifetime Roofing System or ask for a roof inspection, give us a call at (828) 222-0706 or fill out our contact form.