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  • Writer's pictureShannon George

Roofing 101: Anatomy

Updated: Apr 19, 2022

Previously, we discussed the different types of roof structures. Now we discuss the various components that make up a roof. In short, it will be an explanation of the anatomy of a roof, the layers that give it structure and protect the home. Aside from shingles, some multiple parts and layers come together that allow your roof to provide shelter and protection. Read on to learn the common parts of a roof as well as its purpose. Solid working knowledge of the roof and its parts will help you to effectively discuss roof repairs or replacements with your roofing contractor.

Roof Frame

The structure of a roof is the first stage in building a roof. The structure is made up of rafters and trusses, which give a roof its shape and form. With the shape of the rafters and beams, the roof ridge is established. It is the horizontal line that traverses the length of the roof and connects two roof planes. This forms the peak of the roof and will need special shingles. The roof structure will also incorporate the ridge vent, which runs along the top of the roof and allows warm damp air to escape from the attic. This framed structure supports the sheathing or decking layer, upon which all other sections of the roof are stacked and erected.

  • Plank decking

  • Sheet decking


Consider a chimney to understand the need for flashing. Chimneys don't have shingles or underlayment, but things are in place to prevent water from getting into the home. Chimney caps are put on the top to keep water from flowing down the chimney. Flashing is what is used to prevent water from running down the exterior of the chimney.

There are many roof flashing applications. You will see flashing installed around other residential roof features, including:

  • Chimney flashing.

  • Skylight flashing.

  • Plumbing vent flashing.

  • Roof vent flashing.

  • Valley flashing.

  • Dormer flashing.


Roofing underlayment is a substance that acts as a fabric-like barrier layer on top of the roof deck and underneath the shingles. It acts as a moisture repellent and protects against water intrusion. It is put directly to the decking and serves many purposes. It protects the shingles from any resin released by the decking, acts as a water barrier if water seeps under the shingles, and provides some fire protection.

Underlayment may be used to avoid "picture framing." This term is a way to explain how roof shingles bulge in a pattern of "frames" around panels. Expansion and contraction of the roof deck panels cause this. When the light shines on the roof, the contour of each insulated panel is easily visible. . In addition to being unappealing, these elevated patches may obstruct water drainage from the roof. There are different kinds of underlayment

  • asphalt-saturated felt

  • rubberized asphalt

  • non-bitumen synthetic

Ice and Water Protector

An ice and water barrier is a thin self-adhered waterproofing membrane used along eaves, valleys, sidewalls, and other vulnerable locations to protect against ice damage and wind-driven rain. It is installed under the shingles to protect against ice jams and wind-driven rain. It may be especially advantageous in locations prone to harsh weather, such as strong winds and hurricane-prone areas. It is crucial to remember that if the attic has inadequate and ineffective ventilation, the ice and water shield may fall short of its mark in terms of not letting moisture behind the shingles. Ice and water protectors give an extra layer of protection to the roof's most susceptible areas, such as valleys, around skylights, and the edge.


The most commonly known part of a roof is the shingles. Over the last 100 years, asphalt shingles have been the most prevalent shingle on American homes. There are three styles of asphalt shingles.

  • Traditional 3-Tab

  • Laminated Dimension (Lifetime Architectural)

  • Luxury Shingles

Roof Edge

The ultimate role of your roof is to protect your home from moisture. The protection doesn't end with the placement of shingles. You must keep water from running off the roof and down the sides of your home. Otherwise, the water can damage the home or collect at the ground level of the home and cause foundation problems for the house. Preventative measures are put in place around the roof's edge.

  • Drip edge is a narrow strip of noncorrosive metal used at the rake and eave to help manage dripping water by facilitating water runoff to protect the underlying section of a wall.

  • Fascia.

  • Gutters and downspouts.

  • Soffit.

Knowledge of a roof and its parts gives you the ability to master and recognize the layer-by-layer process that makes up the roof. With a comprehensive understanding of a roof's makeup and layers, you will have the confidence to ask the proper questions when selecting a roofing contractor for your next roofing project. If you find you still have questions or are ready to move forward on a roofing project, contact us and one of our qualified experts will be in touch to help determine what roofing system would be best for your home.


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