Common Parts and Layers of a Roof

Not sure what makes up a roof besides shingles? Use our numbered roof diagram to familiarize yourself with the common parts of a roof and its layers so you can confidently communicate with your roofing contractor during your next roofing project.

This is a numbered diagram of a residential roof. The numbers in the diagram correspond to the numbered list in this blog post which label and define the common parts and layers of a residential roof with asphalt roofing shingles.

Diagram: Anatomy of a Roof – Common parts and layers of a residential roof with asphalt shingles

What are the common parts of a roof?

  1. Roof Ridge: The roof ridge, or ridge of a roof is the horizontal line running the length of the roof where the two roof planes meet. This intersection creates the highest point on a roof, sometimes referred to as the peak. Hip and ridge shingles are specifically designed for this part of a roof.
  2. Ridge vent: A ridge vent is an exhaust vent that runs horizontally along the peak of the roof allowing warm, humid air to escape from the attic. Use our ventilation calculator to calculate your attic ventilation requirements and determine how much exhaust ventilation you would need to properly ventilate your roof and attic.
  3. Flashing: Flashing is a metal material installed at joint openings, around chimneys, and any dormer windows or skylights to help prevent water intrusion. You may recognize flashing as metal stair steps alongside a chimney or side walls on a roof.
  4. Hip: The hip on a roof is the intersection of two roof planes that meet to form a sloping ridge running from the peak to the eave. Hip and ridge shingles are specifically designed for this part of a roof.
  5. Roof Deck: The roof deck is the structural foundation base for the roof system and is usually made of wood or plywood.
  6. Roofing Underlayment: Roofing underlayment is a layer of material, usually synthetic or felt, that adds extra protection on top of the roof deck and under the shingles. Synthetic underlayment helps repel moisture and provides protection against water infiltration. Synthetic underlayment is becoming a popular material choice over felt due to proven water-resistance performance and long-lasting durability.
  7. Roof Valley: The roof valley is the V-shaped intersection between two sloping roofs joining at an angle to provide water runoff.
  8. Laminated Architectural Shingles: Laminated architectural asphalt shingles contain more than one layer of tabs to add dimension, performance and durability to a roof. Architectural shingles are sometimes referred to as three-dimensional shingles or laminated shingles. The opposite of architectural shingles are three-tab shingles, which are produced as a single layer of tabs and appear flat or without the dimension of a laminated shingle.
  9. Roof Gable: A roof gable is the triangular section of the outer wall at the peak of the roof between a sloping roof and eave. A roof gable is sometimes referred to as a rake.
  10. Metal drip edge: Metal 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.
  11. Dormer: A dormer is a raised section of the roof. Dormers commonly contain a window that projects vertically through the slope in the roof.
  12. Ice and water barrier: An ice and water barrier is a self-adhered waterproofing material installed along eaves, valleys, side walls, and other sensitive areas to protect against ice damage and wind-driven rain.
  13. Eave: An eave is the lower border of the roof that overhangs the wall usually located in the first three feet of a roof.
  14. Undereave vent: Undereave vents are intake vents located under the eaves of the roof that help draw cool dry air into the attic. Again, you can use our ventilation calculator to calculate your attic ventilation requirements and determine how much intake ventilation you would need to properly ventilate your roof and attic.

Now that you’re familiar with the basic anatomy of a roof, you’ll start to notice dormers and gables everywhere you turn. More important, you’ll be equipped to have an informed conversation with your roofing contractor when the time comes for you to get a new roof.

To learn more about roof layers and components that make up a complete roofing system, visit our Total Protection Roofing System® site section or ask your contractor for more information. Need a roofing contractor? Find a roofing contractor near you in the Owens Corning Roofing Contractor Network.