Comprehensive Roofing Terminology Guide for Southern California
Whether you’re planning a new roof installation, scheduling maintenance, or discussing repairs with your contractor, understanding roofing terminology is essential. At A-1 All American Roofing, we believe informed customers make better decisions about their roofing investments.
This comprehensive glossary covers the most commonly used roofing terms in Southern California, from basic components to advanced installation methods. Use this guide as a reference when consulting with our team or evaluating roofing options for your residential, commercial, or industrial property.
Years of industry expertise mean A-1 All American Roofing speaks your language—literally and figuratively. Let’s demystify roofing together.
Roofing Materials & Components
Understanding the materials that make up your roof helps you appreciate the quality and durability of different systems. Here are the essential material terms:
- Asphalt: A bituminous waterproofing agent applied to roofing materials during manufacturing
- Back Surfacing: Fine mineral matter applied to the back side of shingles to prevent them from sticking together
- Composition Shingles: A thin, pressed roofing material made of asphalt-impregnated fiberglass or organic mat, covered with colored stone granules (also called “comp”)
- Fiber-Cement: A roofing material with cellulose (wood fiber) mixed into it; note that cellulose absorbs water and can increase roof weight while reducing longevity
- Fiber Glass Mat: An asphalt roofing base material manufactured from glass fibers
- Felt (or Tar Paper): A flexible sheet saturated with asphalt and used as underlayment between the deck and roofing material
- Granules: Ceramic-coated colored crushed rock applied to the exposed surface of asphalt roofing products
- Organic Felt: An asphalt roofing base material manufactured from cellulose fibers
- Saturated Felt: An asphalt-impregnated felt used as underlayment between the deck and roofing material
Shingle Types & Styles
Shingles come in many varieties, each with distinct characteristics affecting appearance, durability, and performance:
- Three-Tab Shingles: The most popular asphalt shingle type, typically 12″ × 36″ with three tabs
- Strip Shingles: Asphalt shingles approximately three times as long as they are wide
- Laminated Shingles: Strip shingles containing more than one layer of tabs to create extra thickness (also called three-dimensional or architectural shingles)
- Square-Tab Shingles: Shingles with tabs all the same size and exposure
- Random-Tab Shingles: Shingles with tabs that vary in size and exposure
- HEX Shingles: Shingles with a hexagonal appearance after installation
- No-Cutout Shingles: Shingles consisting of a single, solid tab with no cutouts
- Free-Tab Shingles: Shingles without factory-applied strips or spots of self-sealing adhesive
- Interlocking Shingles: Individual shingles that mechanically fasten to each other for enhanced wind resistance
Roof Structures & Shapes
Different roof designs serve various purposes and offer distinct aesthetic and functional benefits:
- Gable Roof: Contains a triangular gable at each end; the two sloping planes meet at a ridge
- Hip Roof: Sloping planes of the same pitch on each of four sides with no gables
- Shed Roof: Contains only one sloping plane; has no hips, ridges, valleys, or gables
- Gambrel Roof: Two sloping planes of different pitch on each side of the ridge, with the lower plane steeper than the upper; contains a gable at each end
- Mansard Roof: Two slopes on each side with the lower slope much steeper than the upper
- Flat or Low-Sloped Roof: Ideal for commercial applications; can be built-up roofs or single-ply systems
Roof Components & Features
Every roof contains essential structural and protective components. Familiarizing yourself with these terms helps you understand roof construction and maintenance needs:
- Deck: The structural base for the roof, typically made of wood or plywood
- Eaves: The lower border of a roof that overhangs the wall
- Rake: The outer edge of the roof from the eave to the ridge, finishing the gable end
- Ridge: The line of intersection at the top where opposite slopes meet
- Hip: The outside angle formed by the meeting of two sloping sides of a roof
- Valley: The intersection of two sloping roofs joining at an angle to provide water runoff
- Dormer: A vertical opening coming through a sloping roof
- Soffit: The finished underside of the eaves
- Overhang: The portion of the roof structure extending beyond the exterior walls
- Pitch: The angle of steepness of a roof
- Slope: The degree of roof incline expressed as the ratio of rise (in inches) to run (in feet)
- Rise: The vertical distance from the eaves line to the ridge
- Run: The horizontal distance from the eaves to a point directly under the ridge
- Span: The horizontal distance from eaves to eaves
Flashing & Water Management
Proper flashing is critical for preventing water infiltration and leaks. Here are the key flashing-related terms:
- Flashing: Corrosion-resistant sheet metal used in waterproofing roof valleys, hips, or angles between chimneys and roofs
- Base Flashing: The portion of flashing attached to or resting on the deck to direct water flow onto the roof covering
- Counter Flashing: The portion of flashing attached to a vertical surface to prevent water from migrating behind the base flashing
- Step Flashing: Flashing used where a vertical surface meets a sloping roof plane, typically at walls or dormers
- Drip Edge: Non-corrosive, non-staining material along eaves and rakes allowing water run-off to drip clear of underlying construction
- Metal Drip Edge: A narrow strip of non-corrodible metal used at the rake and eave to facilitate water runoff
- Collar: A pre-formed flange placed over a vent pipe to seal the roof (also called a vent sleeve)
- Cricket: A peaked saddle construction at the back of a chimney to prevent snow/ice accumulation and deflect water
Installation Methods & Techniques
How shingles and roofing materials are installed significantly affects durability and performance. Understanding these methods helps you appreciate the craftsmanship involved:
- Normal Slope Application: Method of installing asphalt shingles on roof slopes between 4 and 21 inches per foot
- Low Slope Application: Method of installing asphalt shingles on roof slopes between 2 and 4 inches per foot
- Steep Slope Application: Method of installing asphalt shingles on roof slopes greater than 21 inches per foot
- Concealed Nail Method: Application of roll roofing in which all nails are driven into the underlying course and covered by a cemented, overlapping course
- Exposed Nail Method: Application of roll roofing in which nails are driven into the cemented, overlapping course and exposed to weather
- Open Valley: Method in which shingles on both sides are trimmed along chalk lines; valley flashing is exposed
- Closed Cut Valley: Method in which shingles from one side extend across while the other side is trimmed 2″ from centerline; flashing is not exposed
- Woven Valley: Method in which shingles from both sides extend across and are woven by overlapping alternate courses; flashing is not exposed
- Dutch Lap Method: Application of giant individual shingles with overlap in each course and the course below
- Nesting Method: Reroofing technique where new shingle top edges are butted against existing shingle tab bottom edges
- Racking: Application method in which shingle courses are applied vertically up the roof (not recommended)
Roofing Layers & Coverage
The number of layers in your roofing system affects durability, protection, and longevity:
- Single Coverage: Asphalt roofing providing one layer of material over the deck
- Double Coverage: Application where the lapped portion is at least 2″ wider than the exposed portion, resulting in two layers over the deck
- Ply: The number of layers of roofing (i.e., one-ply, two-ply)
- Course: A row of shingles or roll roofing running the length of the roof
- Exposure: The part of each shingle exposed to the weather
- Coverage: The amount of weather protection provided, depending on the number of material layers between the exposed surface and the deck
- Top Lap: The portion of roofing covered by the succeeding course after installation
- Selvage: The portion of roll roofing overlapped by the succeeding course to obtain double coverage
- Lap: To cover the surface of one shingle or roll with another
Fire Ratings & Performance Standards
Fire ratings indicate how roofing materials perform under fire conditions. This is especially important in Southern California’s fire-prone environment:
- Class A: The highest fire rating a roofing system can achieve; often referred to as fireproof
- Class B: Fire-resistance rating indicating materials can withstand moderate exposure to fire from external sources
- Class C: Fire-resistance rating indicating materials can withstand light exposure to fire from external sources
- UL Label: Label displayed on packaging indicating the fire and/or wind resistance level of asphalt roofing
Materials & Accessories
Various materials and accessories work together to ensure proper installation and long-term performance:
- Underlayment: A layer of asphalt-saturated felt laid on bare deck before shingles are installed
- Bundle: A package of shingles; typically 3, 4, or 5 bundles per square
- Square: 100 square feet of roof area
- Starter Strip: Asphalt roofing applied at the eaves to protect by filling spaces under cutouts and joints of the first course
- Ridge Shingles: Shingles used to cover the horizontal external angle formed by intersecting roof planes
- Hip Shingles: Shingles used to cover the inclined external angle formed by intersecting roof planes
- Battens: 1″ × 2″ × 4′ wood strips nailed to the roof upon which field tile hangs
- Birdstop: A length of formed metal or foam that prevents birds from nesting and positions the first course of tile at the proper angle
- Gutters: A trough along the eaves to catch and carry off rainwater
- Downspout: A pipe for draining water from roof gutters (also called a leader)
- Soil Stack: A vent pipe that penetrates the roof
- Pallets: Wooden platforms used for storing and shipping bundles of shingles
Adhesives, Coatings & Sealants
Various adhesive and coating products are essential for proper installation and long-term waterproofing:
- Caulk: To fill a joint with mastic or asphalt cement to prevent leaks
- Coating: A layer of viscous asphalt applied to base material into which granules or other surfacing is embedded
- Mastic: An asphalt-based cement used to bond roofing materials (also called flashing cement)
- Lap Cement: Asphalt-based cement used to adhere overlapping plies of roll roofing
- Plastic Cement: A compound used to seal flashings and shingles for small waterproofing jobs (apply about the size of a half dollar unless otherwise specified)
- Self-Sealing Cement: A thermal sealing tab cement built into shingles that bonds them together after proper application and warm sun exposure; hand sealing may be needed in winter
- Roofing Tape: An asphalt-saturated tape used with asphalt cements for flashing and patching
- Saturant: Asphalt used to impregnate organic felt base material
- Release Tape: A plastic or paper strip applied to the back of self-sealing shingles preventing them from sticking in bundles (no removal needed for installation)
- Specialty Eaves Flashing Membrane: A self-adhering, waterproofing shingle underlayment designed to protect against ice dams or wind-driven rain
Common Issues & Conditions
Understanding potential roofing problems helps you recognize when maintenance or repairs are needed:
- Blisters: Bubbles that may appear on asphalt roofing surfaces after installation
- Condensation: The change of water from vapor to liquid when warm, moisture-laden air contacts a cold surface
- Telegraphing: Shingle distortion that may occur when new roofing is applied over an uneven surface
- Shading: Slight differences in shingle color resulting from normal manufacturing operations
Installation Tools & Layout Techniques
- Chalk Line: A line made by snapping a taut string dusted with chalk; used for alignment purposes during installation
- Edging Strips: Boards nailed along eaves and rakes after cutting back old wood shingles; provides secure edges for reroofing with asphalt shingles
- Feathering Strips: Tapered wood filler strips placed along old wood shingle butts to create a level surface when reroofing (also called horsefeathers)
- Cutout: The open portions of a strip shingle between tabs
- Tab: The portion of shingle set off by cutouts; the part exposed to weather
Structural Components
- Joists: Small timbers or metal beams ranged parallel from wall to wall to support floor or ceiling
- Rafters: Any of the parallel beams that support a roof
- Sheathing: The first covering of boards or waterproof material on the outside wall of a frame house or timber roof
- Parapet: A low protective wall extending above the roofline or balcony for support
- Non-Veneer Panel: Any wood-based panel without veneer carrying an APA span rating, such as wafer board or oriented strand board
Roofing Systems & Warranties
- Built-Up Roof: A flat or low-sloped roof consisting of multiple layers of asphalt and ply sheets
- Roll Roofing: Asphalt roofing products manufactured in roll form
- Mineral-Surfaced Roofing: Asphalt shingles and roll roofing covered with granules
- Smooth-Surfaced Roofing: Roll roofing covered with ground talc or mica instead of granules
- Color-Through: During manufacturing, color is mixed throughout material to become integral; when cut, affected areas show the same color as surface
- Life Cycle Cost: The total lifetime cost of a roof, calculated by adding maintenance costs to installed price, then deducting added value at resale
- Non-Prorated Warranty: A warranty providing full replacement costs for covered items during the full warranty term (versus prorated warranties that reimburse a percentage based on roof age)
Ventilation & Moisture Management
- Vent: An opening through which outside air enters the attic space, forcing moisture-laden air out; proper ventilation prevents condensation that can damage roofing and deck materials
- Vent Sleeve: See collar (pre-formed flange over vent pipes)
Ready to Discuss Your Roofing Project?
Understanding roofing terminology empowers you to make informed decisions and communicate effectively with your contractor. Whether you’re evaluating repair options, planning maintenance, or considering a complete roof replacement, A-1 All American Roofing is here to answer your questions.
With years of experience serving the greater Los Angeles region, our licensed and bonded professionals combine technical expertise with a customer-first approach. We’re available 24/7/365 for emergency services and ready to discuss your residential, commercial, or industrial roofing needs.
Contact A-1 All American Roofing today for a free estimate and consultation.
- Call us: (310) 320-0224
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- Services: Residential, Commercial, and Industrial roofing installation, maintenance, inspections, and emergency repairs