10 Essential Parts of a Roof Everyone Should Know

Understanding the different features of your roof is not easy – we list the essential parts you need to know.

Carol J Alexander
Updated Dec 9, 2022
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9 min read

Don’t get caught misunderstanding your roofing quote. Instead, learn all the essential 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 scope of the job to you – and that knowledge might save you a bit of money.

Here, we'll look at 10 essential parts of every roofing system, as well as a few parts of some roofs that are good to know.

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What are the different parts of a roof?

The parts of a roof include components necessary for protecting your home from wind, rain, and sun exposure. They include:

  • A framework to hold everything up. 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. To further protect from moisture, a roof includes flashing at all seams and edges.
  • Vents of various kind. Every home needs ventilation. Depending on your taste and the style of roof, yours will include some type of roof vents.
  • A few things to dress it up a bit. The soffit, fascia, and rake provide a nice edge finish to every roof. But other things like skylights and dormers provide natural light and a bit more space.

Roof trusses

Roof trusses make up the framework 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 that are spaced evenly across the span of the home. The size of lumber used–whether 2x4, 2x6, or 2x8–depends on the span of the roof. Trusses are manufactured in a factory and shipped to the job site. The builder orders the correct size and number of trusses for the home's design. In a timber frame home, typically built using heavy wood timbers interlocked together, the roof is framed with individual rafters and joists instead of trusses.

Roof decking

On top of the trusses lays the roof decking. Also referred to as roof sheathing, a roof deck is made of plywood or OSB (oriented strand board), which measures ½" to ?" thick. The deck's thickness depends on the span of the roof and the material used.

Underlayment

The roof underlayment covers the entire roof deck under the shingles and serves as added protection from water damage. There are two types of underlayment: felt and synthetic. A 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. The most popular type of roofing material used as a covering is shingles. But in some regions, you'll find other options used.

Here are the most popular types.

Asphalt shingles

Asphalt shingles are lightweight, economical, and easier to install than other types of roof shingles. They come in a variety of colors, thicknesses, and styles. Depending on the area of the country you live in, you'll want high-quality wind or hail-resistant shingles. 

Slate shingles

You may see natural slate shingles on historic homes because they are durable, and some varieties can last up to 200 years. However, a slate roof is expensive and heavy. The roof on a newer home must be reinforced before applying slate shingles. But if you want the luxury look of slate, faux slate shingles made of synthetic materials are lighter and more economical.

Cedar shake shingles

Homeowners who love the natural look of wood may choose a cedar roof covering. Cedar is a lighter-weight option but requires a lot of maintenance. It needs regular applications of fire retardants, fungicides, and algaecides. The look of moss growing on a cedar roof may look romantic in photographs, but it can damage the shingles.

Clay tiles

Clay tile is one of the oldest styles of roof covering and, if properly maintained, can last 50 to 100 years. Available in a wide variety of styles and colors, clay roofing tiles are found chiefly on older and luxury homes in hot coastal climates and southwestern communities. Clay tiles are also impervious to deterioration from rot, insect damage, and UV rays. However, they're not impact-resistant. A fallen tree branch or the weight of someone walking on the roof can break the tiles. They are also heavy and expensive.

Metal

Metal roofs are an economical option depending on the type of material used. Metal roofs come in galvanized steel, the least expensive, aluminum, and copper. Copper is the most costly. Aluminum is the most prevalent metal for residential and commercial applications as it doesn't rust or corrode and can be painted. 

To get a complete understanding of how the type of roof covering affects the price of a roof, read our roof shingles cost guide

Ridge and ridge capping

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 capping is the row of shingles that covers the ridge. 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. And, 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. There are several types of roof vents that move air in or out.

Here are the most popular vents.

Exhaust vents

A ridge vent covers an opening in the ridge of the roof. It works in conjunction with vents in the home's soffit. As the warm air rises up and out of the ridge vent, it draws cooler air in through the soffit, creating a natural flow. 

A box vent is a static, low-profile vent that allows hot air to rise and escape the home. They can be installed on most styles of roofs and are rated by the square footage they serve. Therefore, a large home may require several box vents to provide adequate ventilation.

Also called a whirlybird vent, a turbine vent moves in the wind to produce a current that draws the hot air out of the attic space. Some homeowners use them to generate electricity and possibly combine them with solar panels.

Not just a decorative feature, a cupola provides a way for warm air to escape the home. It is a static vent with no moving parts that covers an opening in the roof. The air escapes through louvers on its sides. Unfortunately, cupola vents are the most costly of these options to install.

Intake vents

A soffit vent is an opening in the soffit under the eaves that extend over your home's exterior wall. Soffit vents work with other roof vents to allow airflow in the attic space.

Gable vents are openings in the gable ends of the home. Installed on opposite sides of the structure, they allow for passive cross-ventilation through the attic. They are most effective on ranch-style homes without a complex roof line.

An over-fascia vent is installed over the fascia and behind the gutters. It allows outside air to enter the attic space and push warm air out the ridge vent.

For homes with little to no soffit area, homeowners may choose drip edge vents. Made of corrosive-resistant metal, they act as both the drip edge to shed water at the eaves and rakes of the roof and as a vent, as air travels into the attic through small slits in the material. However, drip edge vents are not recommended in cold climates, as they could lead to ice dams.

Drip edge

The drip edge is metal flashing installed at the roof's edge that channels the flow of water away from the fascia and roof structure. The International Residential Building Code (IRC) requires that a drip edge be installed on a roof because the water flows behind the gutters and damages the fascia and roof deck without it. 

Rakes and eaves

The rake is the edge of the roof on the house's gable end. The eaves are the underside of the roof along the walls or the overhang.

Soffit and fascia

Often mentioned together, the soffit and fascia make up the eaves of your home. The soffit covers the underside of the eave, and the fascia is the facing on the roof's edge that gives your home a finished look.

Flashing

Roof flashing consists of thin metal strips that channel water away from areas vulnerable to leaks, like seams or joints, waterproofing the roof deck. You'll find flashing around the chimney, in the valley of a roof, and around vents.

Other roofing terms worth knowing

Some parts of a roof are only found on some structures, but you may still run into them while researching different roof styles. 

Here are the most common terms.

Valleys and hips

Just as the ridge is the highest point where two planes of a roof meet, the valley is the lowest. You'll find roof valleys 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 flat plane that does not meet at the ridge.

Gable

A home with a gable roof includes two flat planes that meet at the ridge. The gable is the exterior of the wall that fills in the peak made by the roof planes.

Dormer

Dormers are jut-outs in the plane of a roof. They make space for windows to provide natural light and additional headroom in the interior. Many homeowners are fond of dormers because they provide additional living space in attics or low-ceilinged second floors. 

Identify the parts of your roof that need repairs

Understanding roofing terminology doesn't just help when contacting a roofer for service. Now that you understand how a roof is put together and performs to protect your home, you can troubleshoot any problems that may arise before calling for help.

If you see any signs of problems on your roof, like curling shingles or algae growth, then make sure to contact a professional roofing contractor to determine whether you need a roof repair or a new roof entirely.

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