24 Parts of a Roof You Need to Know: Terminology and Function

Whether you need to make repairs or you’re gearing up for a new build, knowing the parts of a roof can prepare you for the process. 

While everyone notices the finish on their roof, not many know about the other materials keeping them safe and dry. The truth is many roof parts are required to stop leaks, redirect water run-off, and protect wood from rot.

Parts of a roof

Here’s a breakdown of roof terminology.

Roofing TermKey Characteristics
TrussesPre-manufactured metal or wood pieces supporting the roof frame.
RaftersLarge triangles made of lumber framing the roof, built on-site, providing custom designs.
DeckingMaterial (plywood, plank sheathing, tongue and groove) over trusses or rafters, forming the foundation for other roofing materials.
UnderlaymentThin material (felt or synthetic) on top of roof decking, protecting it from moisture and rot, integral for the roof structure.
FasciaLong board along the roof's lower edge, both decorative and functional, providing attachment for gutters.
Drip EdgeMetal piece installed at the roof edge, preventing water penetration and directing it into gutters.
Ice and Water ShieldWaterproof membrane protecting vulnerable roof areas from snowfall, preventing melting snow from penetrating small cracks.
FlashingFlat, thin material (often galvanized steel) preventing water penetration in vulnerable areas like valleys, vents, skylights, and roof edges.
Chimney FlashingThin, flat material around chimneys to prevent water entry into the home.
Roof Covering/MaterialShingles, cedar shake, metal, aluminum, or tiles, based on preferences and regional considerations. Asphalt shingles are popular in the U.S. for cost and performance.
EaveRoof edge (also called roof eave) overhanging the home's sidewalls.
SoffitMaterial covering the underside of the roof's eave, visible when standing under the roof's edge. Common materials include wood, fiber cement, vinyl, and aluminum.
Rain GutterWater drainage system attached to the roof's fascia board, directing rain and snow run-off away from the home's foundation.
DownspoutVertical piece attached to the gutter, directing water away from the house.
AbutmentAny roof section joining to a wall higher than it.
RidgeHorizontal line at the top of a sloping roof where two sides meet.
ValleyArea where two sections of the roof meet, forming a downward slope that creates angled interior walls, allowing water runoff.
DormerWindow extending out of a sloped roof, resembling a small room with its own roof.
GablePoint where two sides of a roof come together, forming a horizontal ridge at the top, creating a triangle-shaped roof. One of the simplest and most popular roof styles.
Gable EndSection of the wall underneath the end of a gable roof.
HipPoint where multiple sides of a roof slope downward from the peak. Various types of hipped roofs feature different sloping configurations.
Hipped EdgeTriangle-shaped section formed where the sloped sides of the roof meet.
Flat RoofGently sloped roof that appears flat, commonly used for small additions.
SkylightWindow in the ceiling, also a roof component, requiring proper flashing to prevent leaks. Skylights can be small squares or long rectangles.

Common Roofing Terms


Trusses

Roof trusses are pre-manufactured metal or wood pieces that make up the roof frame, supporting the weight of all roofing materials. 


Rafters

Roof rafters provide the same function as trusses: framing the roof. They look like large triangles made of lumber. But unlike trusses, contractors build rafters on-site. While they’re less popular today, rafters are a more traditional method for framing a roof and allow for custom designs.


Decking

Roof decking goes over your roof’s trusses or rafters and lays the foundation for other materials. There are different types of roof decking (also known as sheathing). These include plywood, plank sheathing, and tongue and groove.

Half-an-inch thick plywood is the most common type of roof decking.


Underlayment

The underlayment is a thin material, usually felt or synthetic, that goes on top of the roof’s decking and underneath the shingles. Underlayment is an integral part of a roof structure, protecting the decking from moisture and rot.


Fascia

The fascia is the long board that runs along the roof’s lower edge. It’s situated at the bottom of the trusses or rafters, and while decorative, it plays a vital role, giving you a place to attach your gutters.


Drip Edge

The drip edge is a piece of metal installed at the edge of the roof. Its purpose is to prevent water from penetrating the roof and to direct water away from your fascia and into the gutters.


Ice and Water Shield

The ice and water shield is a waterproof membrane that protects the most vulnerable places in your roof, such as the valleys, eaves, raked edges, and overhangs. It’s an integral part of a roof if you live in areas with heavy snowfall. The shield prevents melting snow from making its way through small cracks.


Flashing

Roof flashing material is flat and thin (often galvanized steel), preventing water from penetrating vulnerable areas. It goes on valleys, around vents, skylights, roof edges, and where the roof meets the home’s walls.


Chimney Flashing

Chimney flashing is a thin, flat material that goes around chimneys to prevent water from entering the home.


Roof Covering/Material

Your roof covering or roof material can be shingles, cedar shake, metal, aluminum, or roof tiles, depending on your preferences and area. In the United States, asphalt shingles remain the most popular roofing material because of their cost and performance.


Eave

A roof edge is also called a roof eave – it’s the portion of the roof that overhangs your home’s sidewalls.


Soffit

The soffit is the material that covers the underside of the roof’s eave. You can see the soffit if you stand under the edge of your roof and look up. The most common soffit materials include wood, fiber cement, vinyl, and aluminum.


Rain Gutter

Rain gutters are a water drainage system attached to your roof’s fascia board. Most gutters are aluminum and look like long, hollow pieces. The purpose of a rain gutter is to direct rain and snow run-off away from your home’s foundation.


Downspout

The downspout is the vertical piece attached to your gutter that runs down the side or corner of your home. Downspouts direct water collected by the gutters away from your house.


Abutment

A roof abutment is any section of a roof that joins to a wall higher than it. 


Ridge

The ridge is the horizontal line at the top of a sloping roof where two sides meet.


Valley

A roof valley is where two sections of the roof meet, forming a downward slope that creates angled interior walls. The valley allows water to run off the roof.


Dormer

A dormer is a window that extends out of a sloped roof. Dormers look like small rooms with their own roofs. A roof dormer may be small, holding only one window, or long, holding several.


Gable

A roof gable is where two sides of a roof come together, creating a horizontal ridge at the top of the roof. A gable-style roof looks like a standard triangle and is one of the most popular and simplest to build. 


Gable End

A gable end is the section of wall underneath the end of a gable roof.


Hip

A roof hip is where multiple sides of a roof slope downward from the peak. There are many types of hipped roofs, some featuring four sloping sides while others have hips and valleys, creating multiple sections.


Hipped Edge

The hipped edge of a roof is the triangle-shaped section that forms where the sloped sides of the roof meet.


Flat Roof

A flat roof is a gently sloped roof that appears flat. Most flat roofs have a slight pitch that allows water to shed. Flat roofs are common for small additions.


Skylight

A skylight is a window in the ceiling; if you have one, it’s also a roof component. Skylights can be small and square, but most are long rectangles. Skylights require proper roof flashing to prevent leaks.