The Roof System Glossary: Every Part You Need To Know

Jun 23, 2022 | Roofing

Getting your roof replaced? Get to know a bit about the roofing industry lingo before you begin vetting local contractors.
We at Greenawalt Roofing Company give you a head start with a brief list of the basics. Start getting to know the anatomy of your roof now through our roof system glossary.

Parts Of Your Roof

Asphalt Shingles:

Consists of granules and layers of a tar/fiberglass mix. The most popular type of shingle in Pennsylvania, the asphalt shingle comes in a wide variety of colors and styles. There are two main types: three-tab and architectural, though many other types of shingles are available. These shingles are the outermost component of a roofing system and serve as the first layer of protection for your roof deck against the elements.


Flat material (typically, plywood or OSB sheathing) between your roof beams and insulation and the external components of your roof (ice and water shield, shingles, etc.). Also referred to as roof decking or sheathing, this component of your roof may or may not also need to be replaced during the roof replacement process. Greenawalt prefers to use plywood because it is a longer-lasting, more durable material.

Dormer, Roof Dormer:

A portion of a home’s roof that extends horizontally from the main roof, is often used to offer more space and light into the home. There are six main types of dormers. Some are barrel-shaped, others look almost like small houses themselves.

Drip Edge:

Metal flashing is designed to prevent water from sneaking underneath the external components of your roof. Without drip edge (or due to an improperly installed drip edge), rain can seep behind your home’s gutters and damage your roof decking and fascia.


The edge of the roof sticks out over the siding of a house, consisting of fascia and soffit. See “FASCIA” and “SOFFIT” below for more information on these two parts of a roof’s eaves.


Fascia aids in protecting your roof and home from moisture accumulation. The fascia also provides a clean, crisp look to the exterior of your home, hiding the ends of the roof rafters. Fascia board is installed on an angle and horizontally. One of fascia’s most common compositions is wood, but it is also made out of aluminum, fiber cement, PVC, and vinyl.

Flashing, Roof Flashing:

Flashing is a thin piece of angled metal that prevents water from entering your attic through any openings, such as where a chimney meets the end of the roof decking. It is designed to guide the water away from that area. Flashing is often installed underneath asphalt shingles around skylights and chimneys.

HIP, Roof Hip, Roof Hip Joint:

A roof hip is a vertical or diagonal roofline where two roof planes come together and create a slope. Since this is a point and not an even surface, shingles do not lay flat on a roof hip. Also known as a hip ridge.

Ice and Water Shield:

A waterproof adhesive layer of polymer-modified bitumen is installed directly on top of the roof decking. Also called ice and water protector, it is a type of underlayment that serves as the final layer of protection for your deck against water that may have snuck under your shingles.


Typically, a horizontal roofline is where two roof planes come together and create a slope. Since this is a point and not an even surface, shingles do not lay flat on a roof ridge. Most effective roof ventilation systems also feature ridge vents. See “VENTING/VENTILATION” below.


The external area of your home where the roof comes together with the siding. The soffit serves as part of your home’s ventilation system, allowing cool air to enter while the exhaust vent allows the release of hot, humid air.

Valley, Roof Valley:

While hips and ridges are the top points of a roof’s slope, a valley is the bottom point where two slopes come together. When it rains, valleys ensure the water funnels safely off of the roof and into the house’s gutters.

Venting/ventilation, Ridge Vent:

A system comprised of exhaust vents and intake vents that help maintain proper air circulation for your home–and to keep your roof in good condition. A well-kept roof has a solid ventilation system with many components. At Greenawalt Roofing, we often recommend homeowners consider Air Vent ventilation products.

Ready To Replace Your Roof?

Find a contractor you can trust. Be sure to do your research and ask the right questions when hiring a roofing contractor. Greenawalt Roofing Company serves multiple communities in Pennsylvania, from Reading to Pittsburgh. Our SELECT ShingleMaster contractors, certified by CertainTeed, use only top-quality roofing materials, and we offer a 12-year workmanship warranty. Reach out to us today to schedule your free roofing estimate and get your project started.

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