The 9 Main Parts of a Roof (Other Roofing Terminology to Know)

If you just got the news that you need a new roof, you’re about to start a confusing and expensive process. Because you’re about to invest your hard-earned money in a replacement, you need to learn as much as possible.  

The truth is, trying to learn everything about a roof and a replacement can be an overwhelming experience. That’s why you have to start with the basics, which begin with understanding the different parts of a roof. 

With over 30 years in the roofing industry, Bill Ragan Roofing has seen way too many homeowners go into the roof replacement process with no knowledge. This leads to the potential of being taken advantage of or making the wrong purchasing decisions on bad advice. 

We want to avoid this happening to you, so let’s get to the basics of understanding roofing by learning the 9 main parts of a roof. 

1. Roof decking (roof sheathing)

Roof decking (also known as roof sheathing) is the wooden boards (plywood or planks) that make up the framing of your roof.

It’s the foundation of your entire roof system and what your roofing materials are installed on. If your roof’s decking is rotten or it can’t handle materials being installed on it, it’ll need to be replaced when getting a new roof. 

Unfortunately, you won’t know if or how much will need replacing until your old roof is torn off. 

2. Drip edge

Drip edge is metal flashing installed at the roof’s edges (eaves and rakes) to keep water away from your fascia and from getting underneath your roofing components.

Without drip edge, water gets behind your gutters and leads to both your fascia board and roof decking rotting out.

It’s also a building code that drip edge is required on a roof and that it must be installed correctly. If your roof doesn’t have drip edge, it’s going to be a lot harder to pass a home inspection because your roof isn’t up to code.

3. Ice and water shield

Ice and water shield is a waterproof membrane used to protect your roof from ice and water damage.

Its main purpose is to protect your roof decking if water gets underneath your roofing material (asphalt shingles, metal roof, etc.).

It’s crucial to have ice and water shield installed on/around certain areas of your roof, like roof valleys, around penetrations, and on roofs that have a 2/12, 3/12, or 4/12 pitch. Because of its importance, every roof needs to have it.

4. Roof underlayment 

Roof underlayment is a felt (15 lb, 30 lb, or synthetic) roofing material that sits between your roof decking and your shingles.

Underlayment is the last line of defense for your roof decking if water gets underneath your roofing materials. 

It’s installed directly over your roof decking and provides an extra layer of protection from the elements. Because of its importance, you need to invest in the best underlayment possible. 

5. Starter shingles

Starter shingles are a pre-cut row of roofing material that goes underneath the first course of shingles before they’re installed.

It makes sure that there's roofing material between the joints where the shingles butt against each other on the edges of your roof. 

Starter shingles also have an adhesive to ensure the first row of shingles are sealed at the eaves and along the rakes. This seal helps improve your roof’s resistance to strong winds.

6. The type of roofing material you choose

The biggest part of your roof is the roofing material that’s used. This could be asphalt shingles, metal roofing, cedar shake roofing, synthetic roofing, or any other type of roofing material. 

The roofing material you choose has a huge impact on the price, how long your roof will last, and more. If you’re unsure what type of roof fits your needs, take this Roof Type Quiz to find the right roofing material for you. 

7. Roof flashing

Roof flashing is a thin metal (aluminum, steel, or copper) material that directs water away from certain areas (walls, chimneys, roof valleys) of your roof.

It’s a crucial roofing component that every roof needs to have and is installed at the same time as your shingles. 

No matter what kind of metal it’s made of, your roof flashing should outlive the original roof it was installed on. However, it’s crucial that your roof flashing is inspected as part of annual roof maintenance to prevent or catch potential leaks.

8. Ridge capping

Ridge capping is the trim installed at the top of where two slopes of a roof meet.

It’s installed at the ridge after all the shingles have been installed.

Ridge capping is thicker than regular shingles and pre-bent, so they can form to the ridges on a roof. Some roofing contractors use 3-tab asphalt shingles as ridge capping to cut down their costs for an asphalt roof replacement. 

This will lead to a roof leak because they’re not meant to be used in this way. It’s absolutely crucial to use the manufacturer’s ridge capping accessory when getting a dimensional or luxury asphalt roof. 

9. Roof vents

Roof vents allow your attic and home to breathe properly.

Without a proper ventilation system, your roof’s life will be cut drastically short due to trapped hot or cold air. 

The two ventilation systems (active and passive) have different roof vents to choose from. If you have an active ventilation system, you’ll choose turbine vents, power vents, ridge vents with a baffle, or solar-powered vents. 

For a passive ventilation system, you choose from static vents (box vents), ridge vents without a baffle, or gable-end vents. I recommend an active ventilation system for performance reasons. 

More roofing terminology you need to know 

Now you know the 9 main parts of a roof. However, there are still some terms that you need to know to help you understand roof lingo when talking to a roofing contractor or doing more research. 

Rakes and eaves

Rakes and eaves refer to the edges of your roof. Rakes are the edge of a roof that runs at a slope.

Eaves are the edge of a roof that runs horizontally; think of it as the gutter line.

Roof facets

Roof facets refer to the different sections or the sides of a roof.

(Roof with a lot of facets)

The more complex your roof is, the more facets it will have. 

Roof valleys and hips

Roof valleys are when two roof facets meet at a slope to form an interior angle. Valleys allow water to flow properly down a roof. 

A hip is when two roof facets meet at a slope to form an exterior angle. 

Gable

A gable is a triangular section underneath where two roof facets overhang a wall.

It's commonly used to refer to a popular ventilation spot, the gable end vent.

Fascia

Fascia is located right below the rakes and the eaves of your roofline.

It serves a decorative purpose, but it can also serve a practical purpose as your drip edge.

Soffit

A soffit is installed right underneath the fascia, where a roof overhangs a wall.

It's common for roofers to install an intake vent right where a soffit is located.

Dormer

A dormer is a section of roof that juts out and forms its own little small section of mini roof.

You’ll usually see a dormer as a window on most roofs.  

What do you need to know about a roof replacement?

Now you know some basic roofing terminology. If you want to learn even more terms that will help you understand your contractor better, check out Roofing Terms and Definitions: Roofing Terminology You Need to Know. 

After reading this article, you’re ready to move on to the next step of your research, learning what a roof replacement is. Not only do you need to know what it is, but you need to learn some important things about it. 

To help you even further, we wrote another article breaking down what a roof replacement is and 6 things you need to know before getting one. 

Since 1990, the team at Bill Ragan Roofing has provided high-quality roofing services and a roofing education to homeowners in Nashville and surrounding areas. Whether you use us or not, we can at least give you the information needed to make the right decisions. 

Check out What is a Roof Replacement? (6 Things to Know Before You Get One) to continue your researching journey into the roofing industry.