Roofing Terminology Glossary: 100+ Terms Defined

Understanding roofing terminology helps you communicate with contractors, read estimates, and make informed decisions.

Most Common Terms You Need to Know

Square (100 sq ft) Pitch (slope ratio) Flashing Underlayment Drip Edge Ridge Vent Eave Valley

A

Architectural Shingles
Multi-layered asphalt shingles with a dimensional appearance that mimics wood or slate. Also called dimensional or laminated shingles. See our architectural vs 3-tab comparison.
Asphalt
A dark, petroleum-based waterproofing material used to coat shingles, felt, and roofing membranes.
Attic Ventilation
The system of intake and exhaust vents that allows air to circulate through the attic space, removing heat and moisture. See our ventilation calculator.

B

Batten
A strip of wood or metal fastened across rafters to support roofing material, commonly used with tile and some metal roof systems.
Bird Stop
A device installed at the eave of a tile roof to prevent birds and debris from entering the space under the tiles.
Blind Nailing
Nailing in a location that will be concealed by the next course of roofing material.
Box Vent
A static exhaust vent installed on the roof slope, also called a turtle vent or static vent. See our ridge vent vs box vent comparison.
Bundle
A package of shingles. Three bundles typically cover one roofing square (100 sq ft).
Butt Edge
The bottom exposed edge of a shingle tab.

C

Cap Sheet
The top layer of a built-up or modified bitumen flat roofing system, often with a granule surface.
Caulk
Sealant material used to fill small gaps and joints. Should be used sparingly in roofing -- mechanical flashing is preferred for long-term waterproofing.
Chalk Line
A line snapped on the roof deck or existing shingles to guide straight shingle courses.
Class A / B / C Fire Rating
UL fire resistance ratings for roofing. Class A offers the highest resistance; most asphalt shingles and metal are Class A.
Closed Valley
A valley where shingles from one side overlap the valley center, covering the shingles from the other side. Creates a clean appearance.
Collar / Boot
A flanged fitting placed over a vent pipe to seal the roof penetration. Also called a pipe boot or vent boot.
Counter Flashing
Metal flashing embedded in or attached to a wall or chimney that overlaps the base (step) flashing below.
Course
A horizontal row of shingles running the length of the roof.
Cricket
A small peaked structure built behind a chimney to divert water around it. Also called a saddle.
Cupping
Shingle distortion where the middle of the tab rises higher than the edges, creating a concave shape.
Curling
Shingle distortion where the edges turn upward. A sign of aging, poor ventilation, or moisture damage.

D

Deck / Sheathing
The structural surface (plywood or OSB) nailed to the rafters that forms the base for all roofing materials.
Dimensional Shingles
Another name for architectural/laminated shingles.
Dormer
A windowed structure projecting from a sloped roof, creating additional headroom and light in the attic.
Drip Edge
An L-shaped metal strip installed along eaves and rakes to direct water away from the fascia and into the gutter.

E

Eave
The horizontal lower edge of a sloped roof that overhangs the exterior wall.
EPDM
Ethylene propylene diene monomer -- a synthetic rubber membrane used for flat/low-slope roofing. See our EPDM vs TPO comparison.
Exposure
The portion of each shingle or tile that is visible after installation. For standard shingles, typically 5 to 5-5/8 inches.

F

Fascia
The vertical board running along the eave to which gutters are typically attached.
Felt (Tar Paper)
Asphalt-saturated paper used as roofing underlayment. Available in 15 lb and 30 lb weights. See our felt vs synthetic comparison.
Flashing
Thin metal pieces used to waterproof roof intersections, penetrations, and transitions (valleys, chimneys, walls, vents).
Flat Roof
A roof with a slope of less than 2:12. Requires specialized membrane or built-up roofing systems.

G

Gable
The triangular wall section formed by two sloping roof planes meeting at a ridge.
Galvalume
A steel coating of aluminum (55%) and zinc (45%) that provides superior corrosion resistance for metal roofing.
Gambrel
A roof with two slopes on each side -- a steeper lower slope and a flatter upper slope. Common on barns and Dutch Colonial homes.
Granules
Crushed rock particles coated with ceramic pigments that are embedded in the asphalt surface of shingles. They provide UV protection and color.

H

Hip
The sloped external angle where two roof planes meet. A hip roof has hips instead of gables on all sides.
Hip Roof
A roof where all four sides slope downward from the ridge to the eaves, with no vertical gable walls.

I

Ice and Water Shield
A self-adhering waterproof membrane installed at eaves, valleys, and penetrations to prevent leaks from ice dams and wind-driven rain.
Ice Dam
A ridge of ice at the eave that prevents melting snow from draining, causing water to back up under shingles.
Impact Resistance (Class 1-4)
UL 2218 rating for shingle resistance to hail impact. Class 4 is the highest, surviving 2-inch steel ball impacts.

J-K

J-Channel
A metal channel used to receive and secure the edge of a roofing material or flashing.
K-Style Gutter
The most common residential gutter profile, with a flat bottom and decorative front face resembling crown molding.
Kynar / PVDF
A premium paint finish for metal roofing that resists fading, chalking, and UV degradation for 30+ years.

L

Laminated Shingles
Shingles made of two or more layers bonded together. Another name for architectural/dimensional shingles.
Lean-to
A single-slope roof attached to a taller wall.
Low-Slope
A roof with a pitch between 1:12 and 3:12. Requires different materials and installation methods than standard-slope roofs.

M

Mansard
A four-sided roof with a steep lower slope and a nearly flat upper slope, creating maximum usable attic space.
Modified Bitumen
A flat/low-slope roofing membrane made of asphalt modified with rubber or plastic polymers for improved flexibility.

N

Nail Pop
A nail that backs out of the deck, pushing up through the shingle above it. Creates a potential leak point.
Net Free Area (NFA)
The unobstructed area of a vent through which air can flow, measured in square inches. Used to size ventilation systems.
Nesting
Installing a second layer of shingles by butting the new shingle courses against the existing cutout lines. Not recommended by most professionals.

O

Open Valley
A valley where both sides of shingles are trimmed back from the center, exposing metal flashing in the valley channel.
OSB (Oriented Strand Board)
An engineered wood panel made from compressed wood strands, commonly used for roof sheathing as an alternative to plywood.
Overhang
The portion of the roof structure that extends beyond the exterior walls. Also called the eave or soffit area.

P

Pitch
The slope of a roof expressed as the ratio of rise to run (e.g., 6/12 means 6 inches of rise per 12 inches of horizontal run). See our Roof Pitch Calculator.
Plywood
Layered wood panels used for roof sheathing, available in CDX grade for exterior use.
Purlin
Horizontal structural members spanning between rafters or trusses, used to support metal roofing panels.

R

Rafter
A structural framing member running from the ridge to the eave, supporting the roof deck.
Rake
The sloped edge of a roof along the gable end.
Ridge
The highest horizontal line of the roof where two sloping planes meet.
Ridge Vent
A continuous ventilation opening along the ridge, covered by a vent product and ridge cap shingles.
Rise
The vertical height difference between the eave and the ridge.
Run
The horizontal distance from the eave to a point directly below the ridge.

S

SBS Modified
Styrene-butadiene-styrene -- a rubberized polymer added to asphalt to improve flexibility, especially in cold temperatures.
Self-Sealing Strip
A factory-applied adhesive strip on shingles that bonds to the course above when activated by heat.
Soffit
The finished underside of the roof overhang, often containing vents for attic intake ventilation.
Square
A roofing measurement equal to 100 square feet. Materials are priced and sold per square. See our guide to calculating squares.
Standing Seam
A metal roofing system with raised interlocking seams and concealed fasteners. See our standing seam vs corrugated comparison.
Starter Strip
The first course of shingles installed along the eave, placed upside down or using purpose-made starter products to seal the first course.
Step Flashing
Small L-shaped metal pieces woven into each shingle course where the roof meets a vertical wall.

T

Tab
The exposed portion of a shingle below the self-sealing strip.
Tear-Off
The removal of existing roofing materials down to the deck before installing a new roof.
Three-Tab Shingles
A single-layer asphalt shingle with three uniform tabs cut into the lower edge.
TPO
Thermoplastic polyolefin -- a white single-ply membrane for flat/low-slope roofing.
Truss
A pre-engineered structural frame (triangle shape) that supports the roof, used instead of individual rafters.

U

Underlayment
A water-resistant material installed on the deck beneath the roofing material. Can be felt (tar paper) or synthetic. See our underlayment guide.

V

Valley
The internal angle where two sloping roof planes intersect, creating a channel that collects and directs water runoff.
Vapor Barrier
A material that resists the passage of moisture vapor, installed on the warm side of insulation to prevent condensation in the attic.
Vent Boot
A rubber or metal collar placed over a vent pipe penetration to create a watertight seal.

W-Z

Woven Valley
A valley construction where shingles from both sides are alternately overlapped across the valley center.
W-Valley
A metal valley flashing with a raised center ridge (W profile) that prevents water from crossing the valley center.
Zinc Strip
A metal strip installed near the ridge that releases zinc particles in rain to inhibit algae and moss growth on shingles.

For material-specific questions, explore our Shingle Calculator and Roof Area Calculator.