Roofing Glossary: A-Z Definitions
Understanding roofing terminology helps you communicate effectively with contractors, evaluate proposals, and make informed decisions about your roofing project. This comprehensive glossary covers 58+ essential terms used in the roofing industry.
Showing 58 of 58 terms
Asphalt Shingles
The most common residential roofing material in North America, made from a fiberglass or organic mat coated with asphalt and mineral granules. Available in three-tab (flat, uniform appearance) and architectural/dimensional (thicker, textured appearance) styles. Typical lifespan of 20-35 years.
Architectural Shingles
Also called dimensional or laminated shingles. A premium type of asphalt shingle with multiple layers bonded together, creating a thicker, more textured appearance that mimics natural materials. More durable and wind-resistant than three-tab shingles, with 25-35 year lifespans.
Attic Ventilation
A system of intake vents (usually at soffits) and exhaust vents (at or near the ridge) that allows air circulation through the attic space. Proper ventilation prevents moisture buildup, ice dams, and premature aging of roofing materials. Building codes typically require 1 square foot of ventilation per 150 square feet of attic space.
Bonding
A surety bond that provides financial protection to homeowners if a contractor fails to complete work, violates building codes, or doesn't pay subcontractors. Acts as a form of insurance backed by a third-party surety company. Many states require contractors to be bonded.
Built-Up Roof (BUR)
A traditional flat or low-slope roofing system consisting of alternating layers of bitumen (asphalt or coal tar) and reinforcing fabric, topped with gravel or a cap sheet. Known for durability and waterproofing. Common on commercial buildings. Also called a 'tar and gravel' roof.
Cap Sheet
The top layer of a built-up or modified bitumen roofing system. Typically a mineral-surfaced or smooth-surfaced sheet that provides UV protection and weathering resistance to the layers beneath.
Certificate of Insurance (COI)
A document issued by an insurance company verifying that a contractor has active insurance coverage. Should list policy types (general liability, workers' compensation), coverage amounts, effective dates, and the insurance carrier. Homeowners should request this before any work begins.
Chalk Line
A marking tool used during roof installation to create straight reference lines for aligning shingles, tiles, or other roofing materials. Ensures uniform courses and straight rows across the roof surface.
Class 4 Impact Resistance
The highest rating on the UL 2218 impact resistance scale for roofing materials, indicating superior resistance to hail and impact damage. Class 4 rated shingles can withstand the impact of a 2-inch steel ball dropped from 20 feet. Many insurance companies offer premium discounts (10-35%) for Class 4 rated roofs.
Closed-Cut Valley
A valley installation method where shingles from one roof plane extend across the valley and are overlapped by shingles from the adjacent plane, which are then trimmed along a chalk line. Provides clean appearance and good water drainage.
Cool Roof
A roofing system designed to reflect more sunlight and absorb less heat than standard roofs. Achieved through reflective coatings, light-colored materials, or specially engineered products. Can reduce cooling costs by 10-30% in warm climates. ENERGY STAR certified cool roof products meet minimum solar reflectance standards.
Counter-Flashing
Metal flashing installed into masonry joints (such as on chimneys) that overlaps and protects the top edge of step flashing or base flashing below. Prevents water from entering behind the flashing system. Critical component for waterproofing roof-to-wall transitions.
Course
A horizontal row of shingles, tiles, or other roofing materials running across the roof from one side to the other. Courses are installed from the bottom (eave) upward toward the top (ridge), with each course overlapping the one below.
Cricket
A peaked construction, also called a saddle, built behind a chimney or other roof projection to divert water and prevent debris accumulation. Building codes typically require crickets behind chimneys wider than 30 inches. Essential for preventing water pooling and leaks.
Deck/Decking
The structural substrate, typically plywood or oriented strand board (OSB), that is attached to the roof rafters and serves as the base for all roofing materials. Also called sheathing. Standard residential decking is 7/16-inch or 1/2-inch OSB or 1/2-inch CDX plywood.
Dormer
A roofed structure that projects from a sloping roof, usually containing a window. Dormers add headroom, natural light, and ventilation to upper stories. Common types include gable dormers, shed dormers, and hip dormers. Dormers create additional roof complexity requiring specialized flashing.
Drip Edge
An angled metal strip installed along the edges of the roof (at the eave and rake) to direct water away from the fascia and into the gutter system. Most building codes require drip edge installation. Typically made of aluminum or galvanized steel.
EPDM
Ethylene Propylene Diene Monomer. A synthetic rubber membrane commonly used for flat and low-slope commercial roofing. Available in black or white, in sheets up to 50 feet wide. Known for durability, flexibility, and ease of repair. Typical lifespan of 20-30 years.
Eave
The lower edge of a roof that overhangs the exterior wall. The eave provides weather protection for the wall below and is where gutters are typically attached. Proper eave construction includes drip edge, starter strip, and ice/water shield in cold climates.
Exposure
The portion of a shingle, tile, or shake that is visible and exposed to weather after installation. For standard three-tab asphalt shingles, the typical exposure is 5 inches. Proper exposure ensures adequate overlap for water protection.
Fascia
The vertical board running along the lower edge of the roof, attached to the ends of the rafters or trusses. The fascia supports the gutter system and provides a finished appearance to the roof edge. Typically made of wood, aluminum, or PVC.
Felt/Underlayment
A layer of material installed between the roof deck and the final roofing material. Traditional asphalt-saturated felt (15 lb or 30 lb) has been largely replaced by synthetic underlayment, which is lighter, stronger, and more water-resistant. Provides a secondary moisture barrier.
Flashing
Thin pieces of metal (typically aluminum, copper, or galvanized steel) installed at roof intersections, penetrations, and edges to prevent water infiltration. Common types include step flashing (walls), valley flashing (valleys), vent flashing (pipe boots), and counter-flashing (chimneys). Flashing failure is the most common source of roof leaks.
Gable
The triangular section of wall between the edges of intersecting roof planes. A gable roof has two sloping sides that meet at a central ridge. Gable roofs are the most common residential roof style in America, offering good water shedding, attic space, and ventilation options.
Granules
Crushed rock or mineral particles embedded in the surface of asphalt shingles. Granules protect the asphalt from UV radiation, provide fire resistance, and give shingles their color. Excessive granule loss (found in gutters) indicates aging shingles that may need replacement.
Hip
The external angle formed where two sloping roof planes meet. A hip roof has slopes on all four sides. Hip roofs are more wind-resistant than gable roofs but more complex and expensive to build. Hip ridges require special hip cap shingles.
Ice and Water Shield
A self-adhering waterproof membrane applied directly to the roof deck before other materials. Used at vulnerable areas including eaves (to prevent ice dam damage), valleys, around penetrations, and at low-slope transitions. Building codes in cold climates require ice and water shield at eaves extending at least 24 inches past the exterior wall.
Impact Resistance Rating
A classification system (UL 2218) that rates roofing materials' ability to withstand impact from hail and debris. Ratings range from Class 1 (lowest) to Class 4 (highest). Many insurance companies offer premium discounts of 10-35% for Class 3 or Class 4 rated roofing materials.
Kick-Out Flashing
A specialized piece of flashing installed at the bottom of a roof-to-wall intersection where the roof edge meets a sidewall. Directs water away from the wall and into the gutter, preventing water from running behind the siding. Often overlooked but critical for preventing wall water damage.
Laminated Shingles
See Architectural Shingles. Multi-layered shingles bonded together to create a dimensional, textured appearance. The term comes from the lamination (bonding) process used in manufacturing.
Mansard Roof
A four-sided roof with a double slope on each side, where the lower slope is steeper than the upper. Named after French architect François Mansart. Provides maximum usable space under the roof and is common in French-inspired architecture.
Metal Roofing
Roofing systems made from metal panels or shingles, including standing seam, corrugated, and stone-coated steel. Available in aluminum, steel, copper, and zinc. Offers 40-70 year lifespan, excellent wind resistance (up to 140+ mph), fire resistance, and energy efficiency. Growing in residential popularity.
Modified Bitumen
A flat or low-slope roofing membrane made from asphalt modified with rubber or plastic polymers for improved flexibility and durability. Applied via torch, hot mopping, cold adhesive, or self-adhesion. Common types include APP (atactic polypropylene) and SBS (styrene-butadiene-styrene).
OSB (Oriented Strand Board)
An engineered wood panel made from compressed wood strands bonded with resin. Commonly used as roof decking/sheathing. Less expensive than plywood but more susceptible to moisture damage. Standard thickness for roof decking is 7/16 inch or 1/2 inch.
Penetration
Any object that passes through the roof surface, including plumbing vents, exhaust fans, chimneys, skylights, and satellite dish mounts. Each penetration requires proper flashing to prevent water infiltration. Minimizing unnecessary penetrations reduces leak potential.
Pitch (Roof Pitch)
The steepness or slope of a roof, expressed as a ratio of vertical rise to horizontal run. For example, a 6/12 pitch rises 6 inches for every 12 inches of horizontal distance. Steeper pitches (above 6/12) shed water faster but are more difficult and expensive to work on. Most asphalt shingles require a minimum pitch of 2/12 or 4/12.
Plywood
An engineered wood product made from thin layers (plies) of wood veneer glued together. CDX plywood is commonly used for roof decking. More moisture-resistant than OSB but typically more expensive. Standard roof decking thickness is 1/2 inch.
R-Value
A measure of thermal resistance used to rate insulation materials. Higher R-values indicate greater insulating effectiveness. Proper attic insulation (R-38 to R-60, depending on climate zone) works with roof ventilation to prevent ice dams, reduce energy costs, and extend roof life.
Rafter
A structural member (typically 2x6, 2x8, or 2x10 lumber) that runs from the ridge board to the eave, supporting the roof deck and roofing materials. Rafters define the roof pitch and bear the weight of all roofing components plus snow and wind loads.
Rake
The inclined edge of a roof running from the eave to the ridge along the gable end. The rake is typically finished with rake trim, drip edge, and sometimes a rake board. Proper rake detailing prevents wind-driven rain from entering under the roofing materials.
Ridge
The highest point of a roof where two sloping planes meet. The ridge runs horizontally along the peak. Ridge cap shingles (specially designed wider shingles) are installed over the ridge for weather protection and finished appearance.
Ridge Vent
A continuous ventilation system installed along the roof ridge, allowing warm, moist air to exhaust from the attic. Works in conjunction with soffit vents (intake) to create natural airflow through the attic space. Provides more uniform ventilation than individual box vents or turbine vents.
Roof Square
A unit of measurement equal to 100 square feet of roof area. Roofing materials (shingles, underlayment) are typically sold and priced by the square. A standard bundle of three-tab shingles covers approximately 1/3 of a square (33.3 sq ft).
Soffit
The underside of the roof overhang (eave). Soffits are typically vented (perforated or with discrete vents) to allow air intake for attic ventilation. Made from vinyl, aluminum, wood, or fiber cement. Vented soffits work with ridge vents for balanced attic airflow.
Soffit Vent
Openings or perforations in the soffit that allow outside air to enter the attic space. Part of the intake system in a balanced attic ventilation strategy. Must remain unobstructed by insulation to function properly.
Solar Shingles
Roofing materials that integrate photovoltaic cells into the shingle design, generating electricity while functioning as traditional roof protection. Examples include Tesla Solar Roof and GAF Energy Timberline Solar. More expensive than traditional panels but provide a more integrated aesthetic.
Standing Seam Metal Roof
A metal roofing system featuring raised interlocking seams that connect adjacent panels. The seams stand vertically above the panel surface, creating a distinctive appearance and highly effective water barrier. Panels are attached with concealed fasteners, eliminating exposed screws. Premium option with 40-70+ year lifespan.
Starter Strip
A row of shingles or dedicated starter material installed along the eave before the first course of regular shingles. Provides adhesive backing to seal the first course against wind uplift and fills the gaps between shingle tabs at the roof edge.
Step Flashing
Small, L-shaped pieces of metal flashing woven into shingle courses where a roof plane meets a vertical wall. Each piece overlaps the one below, creating a stair-step pattern that channels water away from the wall intersection. Critical for waterproofing roof-to-wall joints.
Synthetic Underlayment
A lightweight, tear-resistant roofing underlayment made from polypropylene or polyethylene. Has largely replaced traditional asphalt felt in modern roofing due to superior water resistance, tear strength, UV stability, and ease of installation. Provides a secondary moisture barrier between the deck and roofing materials.
TPO (Thermoplastic Polyolefin)
A single-ply membrane used for flat and low-slope commercial roofing. White TPO is highly reflective, making it popular for energy-efficient 'cool roof' applications. Heat-welded seams provide excellent waterproofing. Typical lifespan of 15-25 years depending on thickness.
Three-Tab Shingles
The most basic and affordable type of asphalt shingle, with cutouts (tabs) that create a uniform, flat appearance. Each shingle has three exposed tabs approximately 12 inches wide. Lighter and less durable than architectural shingles, with typical lifespans of 20-25 years.
Truss
A pre-engineered structural framework, typically triangular, that supports the roof. Trusses are manufactured off-site and installed as complete units, providing consistent quality and faster installation than traditional rafter framing. Most modern residential construction uses trusses rather than individual rafters.
Valley
The internal angle formed where two sloping roof planes meet, creating a channel for water drainage. Valleys handle concentrated water flow and are among the most leak-prone areas of any roof. Proper valley construction requires metal flashing, ice and water shield, and careful shingle installation.
Vapor Barrier
A material that resists the passage of moisture vapor, typically installed on the warm side of insulation to prevent condensation within the building envelope. In roofing, vapor barriers are important in cold climates to prevent moisture from reaching the roof deck and causing rot or mold.
Warranty (Manufacturer)
A guarantee from the roofing material manufacturer covering defects in the product. Standard warranties cover 25-50 years for residential shingles. Enhanced warranties (available through certified contractors) may cover both materials and labor for 25+ years. Review warranty exclusions carefully — most exclude damage from improper installation, extreme weather, and lack of maintenance.
Warranty (Workmanship)
A guarantee from the installing contractor covering labor and installation quality. Typical workmanship warranties range from 2-10 years, though some top contractors offer 25-year or lifetime workmanship warranties. This warranty is only as good as the contractor's continued business operations.
Wind Rating
The maximum wind speed a roofing material is rated to withstand based on ASTM testing standards. Standard asphalt shingles are rated for 60-80 mph winds, while high-wind products can withstand 110-130+ mph. Building codes in hurricane-prone areas require specific minimum wind ratings.
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