You can better understand your roofing quote when you know the terminology. So, it pays to learn all the basic parts of your roof system before calling a roofing professional. Then, as an informed consumer, you'll understand what your roofer means when he explains the job scope to you – and that knowledge might mean money in your pocket.
This illustrated glossary looks at 16 essential parts of every roofing system and a few that are just good to know.
A quick look at roof terminology
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Roof truss |
Wooden triangles spaced evenly across the span of the home to support the roof deck. |
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Roof deck (sheathing) |
Plywood or OSB that covers the trusses and creates a platform for the roof covering |
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Underlayment |
A fabric covering that separates the wooden deck from the shingles to prevent moisture seepage. |
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Roof covering |
Shingles, metal, or tile that covers the entire roof. |
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Ridge |
On a sloped roof, the horizontal line where two planes of the roof meet. |
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Ventilation |
Openings that allow hot air to escape the attic space or that draw in cooler air from outside. |
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Drip edge |
Metal strips at the roof's edge that channel the flow of water away from the fascia and roof structure. |
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Rake |
Edge of the roof on the gable end. |
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Eave |
The underside of the roof where it overhangs the sides of the home. |
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Soffit |
The covering that protects the eave of the roof. |
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Fascia |
The board along the long edge of the roof to which the gutters attach. |
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Flashing |
Metal strips that channel water away from areas prone to leaks. |
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Valley |
The lowest point at which two roof planes meet that creates a channel for water runoff. |
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Hip |
The uppermost point at which multiple sides of a roof meet in a hip-style roof. |
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Gable |
The exterior wall of the house that fills in the end triangle created when two planes meet. |
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Dormer |
A window that juts out of a sloped roof. |
What are the different parts of a roof?
Your roof protects your home from wind, rain, and sun exposure – and it includes multiple parts that all perform a necessary job. We can break these parts into the following categories:
- A supporting framework. Depending on your home’s style, this could include trusses or timber-framed rafters.
- Layers of covering. The different layers include the sheathing or deck, underlayment, and an attractive top covering like shingles or metal.
- Other waterproofing elements. A roof includes flashing at all seams and edges to further protect from moisture.
- Various kinds of vents keep positive airflow in the attic space. The types of vents you choose will depend on your taste and the roof style.
- A few things to dress it up a bit. The soffit, fascia, and rake give every roof a nice edge finish. But other things like skylights and dormers provide natural light and a bit more space.
Roof trusses
Roof trusses create the frame on which the entire roof system rests. They’re also what gives your roof the shape it needs. Simply put, roof trusses are triangles made of dimensional lumber spaced evenly across the span of the home.
The roof span (length) dictates what size of lumber is used–whether 2x4, 2x6, or 2x8. Trusses are manufactured in a factory and shipped to the job site. The builder orders the correct size, style, and number of trusses for the home's design.
In a timber-framed home built using interlocked heavy wood timbers, craftsmen frame the roof with individual rafters and joists instead of trusses.
Roof decking
The roof decking (also called sheathing) lies on top of the trusses and creates a foundation for the other roof materials. It's made of plywood or OSB (oriented strand board), which measures ½" to ⅝" thick. The deck's thickness depends on the span of the roof and the material used.
Underlayment
The roof underlayment (also called the roof sheathing) is a thin fabric covering that lays over the entire roof deck. Placed under the shingles, it protects from water damage and rot. There are two types of underlayment: felt and synthetic. Felt underlayment is made of paper saturated with asphalt and comes in several thicknesses. Synthetic underlayment is made of moisture-resistant, long-lasting polymers.
Roof covering
On top of the underlayment is the roof covering. Composite or asphalt roof shingles are the most popular roofing material used as a covering. But in some regions of the country, you'll find other options used. Here are the most popular types of roof coverings.
- Asphalt shingles
- Slate shingles
- Cedar shake shingles
- Metal shingles
- Clay tiles
- Concrete tiles
- Standing seam metal
- Metal panels
Ridge
A roof's ridge is the highest peak where the sides of the roof meet. A home may have several ridges, depending on the shape and design of the structure.
The ridge may include a few extra components. The ridge capping is a row of shingles that covers the ridgeline. If there is no ridge vent, they are folded over the raw edges of the shingles on either side to give the roof added protection and a finished look. If the roof has a ridge vent, the capping shingles cover it.
Ventilation
Extreme temperatures or moisture in the attic can increase energy costs and damage shingles. Adequate ventilation in the roof prevents this by moving warm or cold air out of the attic space. Several types of roof vents move air in or out.
Exhaust vents allow the attic air to escape. They include ridge, box, or turbine vents. On luxury homes, a cupola acts as an exhaust vent. Intake vents draw fresh air into the attic. They include gable, soffit, and over-fascia vents. Or for homes with little to no soffit, drip-edge vents double as a drip edge and a vent.
Drip edge
Metal flashing creates the drip edge at the roof's edge to channel water flow away from the fascia and into the gutters and downspouts. The International Residential Building Code (IRC) requires a drip edge be installed on a roof to prevent water from flowing behind the gutters and damaging the fascia and roof deck.
Rake and eave
The rake is the edge of the roof on the house's gable end. It's the same board referred to as fascia on the non-gable side of the house. The eave is the underside of the roof that overhangs along the walls.
Soffit and fascia
Often mentioned together, the soffit and fascia make up the eaves of your home. The soffit covers the eave, and the fascia is the facing on the roof's edge, giving your home a finished look. The fascia also provides a place to attach the gutters.
Flashing
Roof flashing consists of thin metal strips (often galvanized steel) that channel water away from areas vulnerable to leaks, like seams or joints, waterproofing the roof deck. You'll find flashing around a chimney or skylight, in the valley of a roof, at the roof edge, and around plumbing vent pipes.
Valleys and hips
Just as the ridge is the highest point where two planes of a roof meet at the top of the roof, the valley is where two planes meet. Roof valleys occur where the roof line changes direction, like in an L-shaped floor plan. A pitched roof design with all sides sloped toward the walls is called a hip roof. The hip is the point where two flat planes meet that aren't the highest point or the ridge. The hip end is the triangularly shaped flat plane on the roof.
Gable
A home with a gable roof includes two flat planes that meet at the ridge. The gable is the exterior wall that fills in the peak made by the roof planes.
Dormer
Dormers are jut-outs in the plane of a sloped roof. They make space for windows to provide natural light and additional headroom in the interior. Dormers come in various styles, but on the outside, most appear to be small rooms with gable roofs. Many homeowners like that dormers provide additional living space in attics or low-ceilinged second floors.
Identify the part of the roof that needs repairs
Sure, knowing roofing terminology helps when speaking with a roofer. But, understanding how roof components are put together and perform to protect your home empowers you to troubleshoot problems as they arise.
When you perform periodic roof inspections (or pay someone to do it for you), you discover signs of wear before you have a major problem. You know it's time to contact a professional roofing contractor when you see things like curling shingles or algae growth. They will let you know whether you need a roof repair or a new roof.
To help you organize your roof care, download our comprehensive Roof Maintenance and Cleaning Checklist.
Frequently asked questions
How much does a new roofing system cost?
The national average to replace a roof is from $15,159 to $27,580, with most homeowners spending about $21,000. Of course, the cost to replace your roof depends on the style of the home, the height and slope of the roof, the roof type, the materials you choose, and your geographic location.
How do I know my roof needs to be replaced?
While performing routine maintenance or a periodic inspection, if you notice missing or damaged shingles, sagging, or signs of water damage, then it's time to call a roofing professional for an opinion. They will let you know if you need a simple repair or a full roof replacement.
How do I choose between all the roofing options?
Choosing between asphalt shingles, metal roofing, slate, wood, or tile is a big decision. Some roofing materials are better suited to certain roof styles than others. Other materials are best for historically accurate renovations. And then, you have a budget to consider. Discuss your ideas with your roofing company to get a professional opinion of the best high-quality materials for your home.
Carol J Alexander is a home remodeling industry expert for Fixr.com. For more than 15 years as a journalist and content marketer, her in-depth research, interviewing skills, and technical insight have ensured she provides the most accurate and current information on a given topic. Before joining the Fixr team, her personal clients included leaders in the building materials market like Behr Paint Company, CertainTeed, and Chicago Faucet, and national publications like This Old House and Real Homes.