21 Different Parts of a Roof

illustration showing anatomy of a roof

Your home’s foundation and roof are arguably the two most important components of your house. Your roof is actually made up of dozens of pieces working together to protect you from the elements, creating an entire roofing system. 

If you’re like most people, you haven’t put too much thought into your roof. But to understand roofing and repairs, it’s important to know the 21 different parts of a roof. 

What Are the Different Parts of a Roof?

Chances are good that you already know a few important components of roof structure, like chimneys, gutters, roof shingles, and rafters. The structure of your residential roof begins with the truss. Your roof’s truss is actually many pieces and is the system that supports your roof. 

1. Decking

Roof decking, or roof sheathing, closes and reinforces your roof and provides a nail bed for roofing materials. Decking acts as the foundation of your roof, supporting and tying your roofing structure together. 

This foundation typically comprises half-inch plywood. It is important for your roofing contractor to install waterproofing material on top of your decking and to ensure your attic is well-ventilated. Excess moisture will swell and shrink your roof’s decking, leading to roof damage, leaks, and structural instability. 

2. Underlayment

Think of your home’s underlayment, or underlayment membrane, as a protective blanket providing cushioning and waterproofing for your roof. Installed directly onto your roof’s deck, the waterproofing material creates a moisture barrier between your home and the outside world

Underlayment membranes comprise many materials, including felt, rubber, reinforced fiberglass, and more. Types include:

  • Rafter underlayment: provides waterproofing for your rafters
  • Valley underlayment: provides additional protection from leaks caused by water pooling 
  • Felt: applied directly to the roof deck and typically covered with shingles to waterproof the roof, the most traditional form of underlayment 
  • Synthetic: provides waterproofing for roof decking like felt, considered a high-tech alternative made from synthetic materials  
  • Eaves membrane: commonly used in cold climates, the self-sealing bituminous membrane protects the roof’s edge from ice dam formation

3. Attic

You may not think about it, but your attic is actually an important part of your roofing system. Also known as the space under your roof, your attic protects your roof from the excessive summer heat and winter moisture through ventilation and allows your roof to breathe. 

4. Vents

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Your roof’s vents are essential to its durability and allow your home to breathe, increasing its structural integrity. There are many types of roof vents, all projecting through the surface of your roof and requiring waterproofing in the form of roof flashing.

  • Plumbing vents: provide ventilation for your home’s plumbing requiring specialized flashing
  • Soffit vents: installed underneath the eaves of your home and combined with other vents to bring fresh air into your attic
  • Ridge vents: installed at the peak of your sloped roof to allow humid air to escape your attic 
  • Gable vents: installed at both ends of your roof’s gables to provide passive attic ventilation

5. Rafter

The rafters of your roof are a key structural component, providing the overall shape or frame of your roof. Connected to exterior walls, rafters are support beams running from one end of your roof to the other and landing on top of your roof’s ridge board

Your rafters provide a base to support your home’s roof deck and roof covering. They are typically made from wood. However, in many commercial builds, rafters are made of metal for additional strength and support. 

Rafters can be left exposed, as you would see in gambrel barn construction, or concealed, as in a typical home. In most residential constructions, battens affix to the rafters perpendicularly to allow for the roof covering attachment. 

6. Ridge

Commonly made from wood or metal, your roof’s ridge, or ridge board, forms the horizontal line at the top of your roof’s peaks, creating the triangle shape. It is the highest point of your roof and connects to the rafters to form your roof’s frame.  

Ridge Tile 

Your roof’s ridge connects two roof sections. However, the joints leave an opening for water to flow through. Ridge gaps are covered with specialized tiles to keep out moisture. Ridge tiles match your roofing aesthetics or can be used to accent them. 

7. Collar Beam

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Collar beams are common in residential construction. These horizontal support beams connect two rafters while intersecting at your roof’s ridge to provide additional stability. These structural beams help frame your ceiling

8. Battens

Your roof’s battens attach to your rafters perpendicularly. Also known as roofing laths, they provide a surface for your roofing materials to be fixed to. The spacing of your roof’s battens depends on the type of roofing material you select. 

9. Joists

Ceiling joists are an internal component of your roofing system. Often composed of wood beams in residential construction, they run along your roof’s interior connecting your rafters. Joists provide extra support for your soffits, eaves, and balconies

10. Soffits

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Soffits are dual-functioning, offering both aesthetic and functional qualities. They are a finishing material that boosts curb appeal while also insulating your home. Soffits cover the underside of your roof’s overhangs to conceal your rafters and joists, preserving the longevity of your roof.

11. Fascia 

Fascia boards run along the edges of your roof, covering rafters and exposed trusses. These strong boards connect your walls with your rooftop and provide support for your gutters. Fascia boards provide curb appeal and are necessary for a polished and finished look. 

12. Rake

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The rake, or gable, on your roof is not technically a roof component. It describes the sloped edges of your gable roof. Rakes can stop flat or create an overhang and eave. 

Your rakes can also be left open or closed with fascia or soffit to match your roof’s aesthetics.

13. Hip 

In hip roof design, all four sides of your roof slope downward toward your walls. Perfect for wet, snowy, or icy climates, these roofs protect the sides of your home with four-sided eaves.   

14. Eaves

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While your roof’s rakes run vertically, eaves, also known as roof edges, run horizontally and are the lowest and weakest points of your roof where water drops to the ground

They are the ideal place for gutter installation. However, because of their weaknesses, they are prone to shingle deterioration and metal corrosion. The primary function of your eaves is to keep water from trickling down the outside walls of your house.

15. Valley

Roof valleys form when two sections of your roof meet to form a v-cut angle. The junction of the two slopes is prone to accumulating water and debris and needs to be equipped with gutters. Your roof’s valleys help direct proper water flow down your roof.

16. Dormer

Dormers, or windows, are a popular roof add-on. Dormer windows project vertically from your roof, supplying natural light to your attic or loft areas

While these windows increase ventilation and usable space by up to 30 square feet, it is important to install energy-efficient windows to filter ultraviolet light and reduce energy costs.  

17. Chimney 

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You probably never realized that your chimney is actually an important component of your roof’s structure. It is a hollow, vertical roof projection that aids in the ventilation of your home, exhausting harmful smoke from your stove, boiler, and fireplace

18. Flashing

Like your underlayment, flashing is part of your home’s weather-resistant barrier system, preventing water infiltration. It comprises thin strips of waterproofing material placed along the joints and seams of your roof. 

Flashing comes in many materials, including galvanized steel, aluminum, and plastic. Important types include:

  • Chimney flashing: installed at the intersection of your chimney and your roof to prevent moisture penetration 
  • Vent pipe flashing: external sealant at vent openings
  • Valley flashing: waterproof roofing material installed in the valley line of your roof 
  • Skylight flashing: waterproofing material installed on top of your skylight’s sealants in between the glass and frame

19. Drip Edge 

Your home’s drip edge is actually a specialized type of metal flashing installed along your roof’s eaves. It reroutes water away from your home and fascia. 

20. Gutters and Downspouts

gutter on top of a roof
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Gutters and downspouts make up their own system and are external roof fixtures. Comprising ducts to direct water away from your home, gutter systems are an essential component to the durability of your home’s foundation and outer walls

21. Covering

Your roof’s covering provides protection, durability, and curb appeal. It comprises any outer material secured to your roof to keep out the elements. 

Roof covering includes shingle, tile, slate, metal roofing, and more. Your choice of covering depends on many factors, including roof type, climate, and budget. 

What Are the Signs You Need to Replace Your Roof?

Roof replacement is expensive, but you can often prevent leaks before they happen. However, if you aren’t paying attention to your roof’s visual clues, roof damage can sneak up on you. 

Watch out for these signs it is time to replace your roof:

  • Damaged, loose, curled, missing, or mossy shingles
  • Damage or discoloration around vents, chimneys, or skylights 
  • Sagging areas 
  • Visible leaks or water damage
  • Grit (flakes of asphalt shingles) in your gutters
  • Your roof is over 20 years old
  • Neighbors are having their roofs replaced

FAQ About the Different Parts of a Roof

How much does a new roofing system cost? 

Typically, new roof systems cost between $8,000 and $21,500 for an average cost of $14,500, but roofing costs vary drastically by region and company. Contractors consider factors like size, materials, structural components, unique features like chimneys or skylights, and old roof removal when determining the cost of your new roof. 

How do I choose the best roofing materials? 

Roofing materials are way more complex than simply heading to your local hardware store and selecting a new paint color for your kitchen. Don’t make the mistake of selecting materials based on aesthetics alone. Consider the following factors when making your decision to ensure you have a functional and eye-pleasing new roof that will last. 

● Climate
● Roof design and slope
● Budget
● Warranties and durability
● Aesthetics

Can exposed rafters be insulated?

Exposed rafters add ceiling height, increase airflow in warm climates, and offer unique aesthetics. However, they also can be harder to insulate, especially in cold northern climates.

While exposed rafter construction offers fewer insulation options, it can be done by: 

● Insulating your roof deck
● Insulating between your rafters
● Adding external cladding to your rafters

What to Do When Part of Your Roof Fails

A roof in poor condition can leak and develop mold, while one in good condition provides protection and warmth. If you are living with drafts, leaks, or unsightly water spots, consult a local roofing professional to discuss which part of your roof may be failing and develop a plan to fix it.

Main Image Credit: Illustration by Juan Rodriguez for RoofGnome

Kimberly Magerl

Kimberly Magerl is a writer and data analyst specializing in home improvement, DIY, roofing, and solar technologies. She enjoys growing vegetables in her garden, getting outdoors, and transforming her space with DIY projects. A resident of Texas, when she isn't gardening, Kimberly enjoys trying new recipes and cooking with her home-grown herbs.