Understanding your roof

Hover over the beacons to learn more about each component of your roof

An open cross-section of roof that shows all the layers of a roof

Roof coverings: The visible, overlapping weatherproof roof covering that sheds water, protects the underlying structure, and adds style to your home. Common roofing covering materials include asphalt (composition) shingles, clay tiles, concrete tiles, slate tiles, solar shingles, metal roofs, silicone and acrylic coatings.

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Attic vents allow air circulation in the attic space to remove moisture and prevent premature roof deterioration. Proper ventilation is crucial for roof longevity. Attic vents with ember-resistant mesh screening are important for fire-hardening in high fire hazard severity zones. 2 of 7 Underlayment: A water-resistant or waterproof material installed beneath the roof covering to prevent leaks if the outer covering is damaged or deteriorates over time. Premium underlayments also provide additional energy efficiency. 3 of 7

Decking: The solid base, typically plywood, that provides a nailing surface for the roof covering.

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Fascia: Horizontal boards attached to the rafter ends along the roof perimeter, providing a surface to mount the gutter system.

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Gutters: Channels that collect and direct rainwater away from the roof and foundation to prevent water damage and soil erosion around the building.

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Attic insulation: Material in the attic floor or between rafters that reduces heat transfer, improves energy efficiency for your home, and acts as a barrier between the unconditioned air in your attic and the conditioned air your family is breathing.

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Most people don’t know all the parts of a roof, what each part does, and why every component is important. That’s normal.

Roofs often get taken for granted until there’s an issue. Many homeowners have never had to purchase a new roof before, as they can last 20 years or more with proper care and maintenance, and many of us go up on our roofs rarely, if at all.

Despite this, your roof is actually one of the most critical components of your home as it protects your greatest asset and investment – your home – and all of your belongings and memories within. 

Understanding the components of your roof will help you make more informed decisions when it comes time for roof repairs, roof replacement, gutter installation, or attic insulation.

This interactive tour will walk you through the key parts of a typical roof and attic space.

As you explore, you’ll learn the purpose of each element and how they work together to provide a weathertight, well-insulated, and long-lasting roof over your and your family’s heads. 

Want a free roof assessment? LocalRoofs’ roofing specialists will come to your home and take you on a guided drone tour of your roof, explaining and making recommendations. Contact us now for your free, no-obligation roof checkup and estimate.

Roofing Terms Explained

Term Explanation

Asphalt shingles

Asphalt shingles (also known as a composition roof) are the most common type of roofing material, popular for the wide range of colors and styles and because they are less expensive than some other roof types. Compare asphalt shingles with other roofing types.

Attic insulation

Attic insulation is the material in the attic floor or between rafters that reduces heat transfer, improves energy efficiency for your home, and acts as a barrier between the unconditioned air in your attic and the conditioned air your family is breathing. There are different types of attic insulation, such as fiberglass blow-in insulation, fiberglass batts and rolls, and cellulose loose-fill insulation.

Attic vents

Attic vents allow air circulation in the attic space to remove moisture and prevent premature roof deterioration. Proper ventilation is crucial for roof longevity. For high fire-risk areas like Southern California, attic vents with mesh screening help prevent embers and burning debris from entering the attic space during a wildfire. These vents have fine metal mesh covers that allow airflow for ventilation, but block entry of airborne hot embers that could ignite materials stored in the attic or start the structural components smoldering. For homes in high wildfire risk areas, attic vents with ember-resistant mesh screening are an important fire-hardening measure.

Clay tiles

Clay tiles are durable tiles made from baked clay, popular in Southern California for their heat resistance. Compare the pros and cons of clay tiles with other roofing types.

Concrete tiles

Concrete tiles are a type of roofing material made from a mixture of cement, sand, and water that is molded into flat or curved tiles. Concrete tiles are very durable and resistant to fire, rot, and impact from hail or debris. They are heavier than asphalt shingles and can give a roof a decorative, Mediterranean-style look. Compare concrete tiles with other roofing types.

Cool roof

A cool roof is designed to reflect more sunlight and absorb less heat, suitable for hot climates like Southern California.


Decking is the solid base, typically plywood, that provides a nailing surface for the roof covering. We typically see wood rot on this layer if the roofing materials above it have deteriorated, cracked, are missing, or otherwise aren’t watertight.


A downspout is a pipe that carries rainwater from the gutter to the ground or drainage system. In combination with the rest of your gutter system, downspouts help channel water away from your roof, walls, and foundation.


Eaves are the edges of the roof that overhang the walls of your home. Eaves help to protect your home from water damage by preventing rainwater from running down the exterior walls.


Fascia is the horizontal boards that run along the edge of the roofline, covering the ends of the roof rafters. Fascia boards provide a finished appearance to the roofline, support the lower edge of the roof, and provide a mounting point for gutters. Fascia boards also help to protect the roof and interior of the home from water damage by preventing moisture from entering the roof structure and the attic. Additionally, they contribute to the overall aesthetic appeal of the building by creating a smooth, continuous edge along the roof.


Flashing is a thin material, typically made of metal, installed around areas of the roof where different surfaces meet, such as chimneys, skylights, and vents, to prevent water from coming into your home. It acts as a barrier that directs water away from these vulnerable junctions, protecting the roof and interior of the home from leaks and water damage.

Flat roof

A flat roof is a roofing system with a minimal slope, typically less than 10 degrees, creating a nearly horizontal surface. This type of roof is common in commercial and industrial buildings but can also be found in residential architecture, particularly in modern or contemporary designs, and often requires specialized waterproofing materials to prevent water accumulation and leakage. Common roofing materials for flat roofs include touch down roofing and silicone and acrylic coatings.


A gable roof has two sloping sides that meet at a ridge, forming a triangle. It's a common architectural feature that provides additional attic space and allows for better ventilation and drainage of rainwater.


Gutters are the metal channels that collect and direct rainwater away from the roof and foundation to prevent water damage and soil erosion around your home.


Roof joists are horizontal structural members that span across the width of a home, supporting the roof and transferring its load to the walls. Joists play a crucial role in maintaining the stability and integrity of the roof by evenly distributing weight and providing a framework to which roofing materials can be attached. Joists are particularly important for heavy roofing materials such as clay, concrete, and slate tiles. These materials exert significant weight on the structure, so the roof joists must be strong and properly spaced to support the load and ensure the roof's stability and safety.


Mastic is a thick, paste-like adhesive used in roofing to seal and waterproof various areas. It's often applied around flashing, in joints, or anywhere a strong, waterproof seal is needed.

Metal roof

Metal roofs are energy-efficient, fire-resistant, long-lasting, and able to withstand harsh weather conditions, making them an excellent choice for both residential and commercial properties. Metal roofs are currently very popular with modern architecture, which favors the clean lines. Compare metals roofs with other roofing types.


Pitch is a measure of the steepness of a roof, expressed as a ratio of the vertical rise to the horizontal span of the roof. It indicates how much the roof rises vertically for every unit of horizontal distance, usually expressed as a ratio. For example, a roof with a 6:12 pitch rises 6 inches for every 12 inches of horizontal run. Roofs with a steeper pitch are more challenging to work on, requiring additional safety measures and equipment and more experienced workers to perform maintenance, repairs, or installations.


Ponding is the accumulation of standing water on a flat or low-slope roof surface, typically due to inadequate drainage or structural deflection.


The ridge is the highest point of a roof, where two roof areas intersect.

Slate tiles

Slate tile roofs are one of the most premium roofing materials. Known for their exceptional longevity and natural beauty, slate roofs provide a timeless and elegant look that can last for generations. Compare slate tiles with other roofing types.


The soffit is the exposed underside area where the roof overhangs the house. It has vents that allow air to enter the attic and ventilate the roof.

Solar shingles

Solar shingle roofs integrate photovoltaic cells into traditional shingles, enabling homeowners to harness the power of the sun and lock in electricity costs while enjoying the aesthetic appeal of a standard roof.


A square in roofing terms is a unit of measurement equal to 100 square feet of roof area. It's the standard unit used by roofers to estimate materials and costs.

Torch down roof

A torch down roof is a type of roofing system that uses modified bitumen sheets, which are adhered to the roof surface using an open flame torch. This process creates a waterproof and durable membrane, making it ideal for flat or low-sloped roofs by providing excellent resistance to leaks, weathering, and UV radiation. Torch down roofing can be used for both commercial and residential buildings.


Underlayment is a protective layer installed between the roof deck and the roofing materials, such as shingles or tiles. It acts as an additional barrier against water, wind, and other elements, providing extra protection to prevent leaks and extending the life of the roof by safeguarding the roof deck from damage. Premium underlayments also provide additional energy efficiency to your roofing system.


Valleys are the angled intersection where two sloped roof sections join together to allow water runoff. If valleys aren't built right with proper flashing and waterproof membranes underneath the roofing, all that concentrated water flow can cause leaks to develop. Debris like leaves and sticks can also get trapped in valleys and lead to moisture problems. Valleys need extra protection and maintenance to prevent water from finding its way through gaps or cracks over the years.

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