roofing terminology guide

Roofing Terminology Guide

A guide of terms often used in roof repair, inspection, and installation.

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A Guide to Roofing Terms

You may need to learn some roofing terminology when engaging with a contractor to work on your roof. When you are talking to a roofing contractor, it may sound like they are talking in a foreign language. There are many terms in the industry that are specific to roofing and you should have a cursory knowledge of at least some of these. 

Of course, you can always ask the roofing contractor to clarify and explain anything that is unfamiliar to you, but having some knowledge is helpful in getting a thorough understanding of the work that is going to be done. And, it makes the conversation so much easier. Everything from identifying a part of your roof to staying on top of the installation process will help you in staying apprised of the project as it moves along.

At Allied Roofing Solutions, your licensed and experienced New Jersey roofers, we get it. You aren’t an expert in roofing and may not know the different terms that we use, but we are always willing to explain anything you don’t understand. You can trust us to provide accurate and clear information during your work with us. To assist you, we are providing this roofing terminology guide so you can familiarize yourself with basic terms.



An aggregate works as a surface for a roofing system. It can be made from many different materials including gravel, stone, rock, slag, and crushed lava rock. All aggregates serve the same purpose – to protect the roof from UV rays.  

Algae Discoloration

Algae discoloration shows up as dark streaks that can adhere to asphalt shingles, shake, slate, metal, and tile. It is sometimes erroneously described as fungus growth.


Alligatoring is typically associated with flat roofs. As a flat roof ages and the sun dries out the topcoat of the roof, alligatoring can occur. This manifests as cracks that worsen with time and ultimately result in the shortening of the flat roof’s lifespan, causing problems with water leakage into the building.

Apron Flashing

Apron flashings create watertight junctions to move moisture away. They are either L- or V-shaped and are usually located against a chimney. An apron flashing exists to move water away from the low end of a curb and toward the gutter system.

Architectural Shingles

Architectural shingles are composed of ceramic-coated mineral granules with a fiberglass base. These are a higher-quality alternative to other types of shingles. Architectural shingles are also called laminated or dimensional shingles. Some architectural shingles are made to look like cedar shakes or slate without the negatives associated with those roof types.

Asphalt Roof Cement

Asphalt roof cement is used to bond roofing materials.

Asphalt Shingles

Asphalt shingles are and have been the most popular roofing material in the U.S. for quite some time. These shingles are affordable and come in a variety of styles and colors. Asphalt shingles are made of a mix of fiberglass, felt paper, asphalt, and ceramic granules. They are affordable but have a shorter lifespan than other roofing materials.


Base Flashing

The base flashing is the portion of flashing that directs the flow of water on the roof. It protects the roof on vertical plane intersections to avoid water buildup and subsequent water damage.


Bitumen is a black viscous mixture that is made from the natural distillation of petroleum. It is waterproof and is used in the reformation of roofing felt and roll roofing for flat roofs.

Blind Nailing

Blind nailing is a process in which nails are placed out of sight and unexposed to the elements. It helps to protect the materials from breaking down over time.


Blisters are bubbles that can appear on the surface of asphalt roofing after installation. It occurs when gas or moisture causes bubbling in the shingle. This appears as a circular blemish like a blister. Generally, this will occur within the first year after installation. Blistering can shorten the lifespan of the roof, especially if the roof is showing blistering on a large scale across the entire roof.


Buckling happens when asphalt shingles won’t stay flat, creating a wrinkled appearance. It is caused primarily during high humidity periods and on older roofs.


Cap Flashing

Cap flashing is the material that is used to cover the top of a base flashing and other types of flashings. It weatherproofs and seals the roofing system at the edges.


A collar is a pre-formed flange placed over a vent pipe to seal the roof around the vent pipe opening. It is also called a vent sleeve.

Cool Roof Shingles

Cool roof shingles are specially designed to remain at lower temperatures than traditional, non-reflective shingles when exposed to the sun’s rays. This can reduce the temperature in the attic and save on cooling costs. Houses in hot climates benefit from this type of shingle.


A cricket is a device that diverts water around or away from chimneys and other large roof projections.


Damp Proofing

Damp proofing is the process of treating the roof’s surface to resist the penetration of water should hydrostatic pressure not exist.


A dormer is a vertical projection from the roof, such as a window that projects through the sloping plane of the roof. A dormer is built into a home to create more usable space.


A downspout is a pipe for draining water from roof gutters.



An eave is the horizontal, lower edge of a sloped roof.

Eave Flashing

The eave flashing is an additional layer of roofing material applied at the eaves to help prevent damage from water backup.



The fascia is a board that is placed along the lower edge of the roof. The gutters are attached to the fascia. It is put in place to protect the edge of your roof from water damage and weather. It also keeps critters like squirrels and birds from getting into the roof.


Felt is the fibrous material saturated with asphalt and used as an underlayment or sheathing paper.


Flashing is a material that is used on a roof to keep water from passing into the structure through a joint. It is part of the barrier system used to protect your home from water. Flashing is usually a thin piece of galvanized steel. It is used around all roof features that may otherwise expose the roof system to water, including chimneys, skylights, and vents.



A gable is the upper triangular portion of a sidewall that comes to a point at the ridge of a double-sloping roof. Gable roofs are the basic residential roof styles. They are made of two roof sections that meet at a point and slope in opposite directions.


Granules are the ceramic-coated colored crushed rock that is applied to the exposed surface of asphalt roofing products.


The gutter is the trough that directs water from the eaves to the downspouts. Gutters are extremely important, as well as the downspouts, to keep water off of the roof. They prevent erosion and keep the foundation and basement intact.


Hip Roof

A hip roof (or hipped roof) is a type of roof design where all roof sides slope downward toward the walls, where the walls of the house sit under the eaves on each side of the roof.

Hip Shingles

Hip shingles are used to cover the inclined external angle formed by the intersection of two sloping roof planes.


Ice Dam

An ice dam is a condition formed at the lower roof edge by the thawing and re-freezing of melted snow on the overhang. This can force ponded water up and under shingles to cause leaks.

Ice Dam Protection

Ice dam protection is achieved by installing a self-adhering underlayment at the eaves of a building to prevent damage from water backup from an ice dam. This is also called an “eave flashing.”


Laminated Shingles

Laminated shingles contain more than one layer to create extra thickness. These are also called “three-dimensional shingles” or “architectural shingles.”


Mansard Roof

A mansard roof is a type of roof containing two sloping planes of different pitches on each of the four sides. The lower plane has a much steeper pitch than the upper, many times approaching vertical, and usually contains dormer windows.

Metal Roof

A metal roof is many times made of corrugated galvanized steel. It can also be made of a blended material of zinc, aluminum, and silicon-coated steel. These types of roofs are durable and routinely last 2 to 4 times longer than shingles and outperform shingles in hail and other severe weather events.

Mineral-Surfaced Roofing

A mineral-surfaced roof is comprised of asphalt shingles and roll roofing that are covered with granules.



Nesting is a method of reroofing with new asphalt shingles over old shingles in which the top edge of the new shingle is butted against the bottom edge of the existing shingle tab.


Organic Felt

Organic felt is used as a base material made from cellulose fibers.


The overhang is the portion of the roof structure that extends beyond the exterior walls of a building. Below the overhang, a soffit is usually installed.



A roof rafter is a part of the roof’s structure. Rafters are placed side by side and provide support back to the roof decks and coverings.


A rake is the inclined edge of a sloped roof over a wall.


The ridge of the roof is where the highest peaks of each roof slope meet and then branch out into different directions.

Roof Ridge Vent

A roof ridge vent is an air slot cut into the roof deck at the highest point on the roof. The vent protects the house inside from the weather while allowing air to flow freely through the attic.



A shingle is a small piece of roofing material designed to be installed in overlapping rows or courses.


The slope is the degree of roof incline expressed as the ratio of the rise, in inches, to the run, also in inches. For example, a roof slope of 4/12 has a 4-inch rise every 12 inches.


A soffit is the underside of the overhang. It protects the rafter and keeps moisture out. Soffits should be inspected twice a year for signs of wear and tear. Eventually, soffits should be replaced to protect the integrity of the roofing system.

Solar Panels

Solar panels are racked modules, separate from and on top of your roof, with the panels attached by dozens of roof penetrations.

Solar Roofing

Solar roofing is a roofing system in which solar is integrated into your home’s roof materials.


A roofing square is a 100-square-foot area. This is how roofs are measured to determine the number of materials a roofer will need to order. It is figured by a simple equation: the total square footage of the home divided by 100.

Step Flashing

Step flashing is an application method for base flashing where a vertical surface meets a sloping roof plane.



A tab is the exposed portion of strip shingles defined by cutouts.

Tear Off

Tear off is the removal of an existing roofing system down to the structural deck. This full replacement results in a brand-new roof. 

Three-Tab Shingle

Three-tab shingles are lightweight asphalt shingles made of three separate tabs that are 12 inches in width. These are generally cheaper options that are far less durable than architectural shingles.


A roof truss is a structural framework that supports the roof. It is made of wood and looks like a skeleton of the roof. Trusses are evenly spaced and are separated by spaces called bays.



Underlayment is a barrier installed under your roof deck for protection. The underlayment is water-resistant and waterproof. Roofing underlayment is available in three types – asphalt-saturated felt, rubberized asphalt, and synthetic.



A roof valley is where two downward-sloping sections of a roof join, creating either a V- or W-shaped depression. It is put in place to direct water off the roof to avoid water buildup.


A vent allows intake or exhaust air from the roof. Vents are generally added to the highest peaks on the roof with the purpose of moderating temperatures in the attic and preventing moisture accumulation.



Weathering is the eventual breakdown of a roof as it nears the end of its expected lifespan. It is caused by several factors: extreme weather conditions, poor installations, improper maintenance, and degradation of the roofing material. Weathering is to be expected when your roof is older.

Weep Holes

Weep holes are drilled into tiled roofs at the ridge to create a way for water behind the tile to drain.

Wind Uplift

Wind uplift occurs when the roof system experiences a higher air pressure beneath it than above it. Fasteners can prevent the roof from detaching from the home. Wind uplift can cause problems such as shingle curling.

Woven Valley

The woven valley is a method of valley construction in which shingles from both sides of the valley extend across the valley and are woven together by overlapping alternate courses as they are applied. The valley flashing is not exposed in a woven valley.

Contact Us for Your Roofing Needs

When you see signs that your roof is needing to be replaced or repaired, contact our team at Allied Roofing Solutions to schedule a free consultation. We will work with you to clarify the terminology and make sure you understand the process. We serve New Jersey residents in Bergen County, Essex County, Hudson County, Middlesex County, Morris County, Passaic County, and Somerset County. Please call us at 201-773-0633 or fill out our free estimate form to schedule your roof inspection or repair.