Roofing & Exterior Terminology
Glossary of Terms
61 definitions of roofing, siding, ventilation, and building-science terms — so you can understand what your contractor is talking about.
3-Tab Shingle
A flat, single-layer asphalt shingle with cutouts creating a three-tab appearance. Thinner and lighter than architectural shingles with shorter warranties.
Air Barrier
A material or assembly that limits the passage of air between the interior and exterior of a building. Helps prevent energy loss and moisture movement through the building envelope.
Algae
A type of growth that appears as dark streaks on roofing materials, particularly in humid, shaded areas. Algae-resistant shingles contain copper or zinc to inhibit growth.
Architectural Shingle
A dimensional, multi-layered asphalt shingle with a thicker, textured appearance that mimics wood shake or slate. Also called laminate or dimensional shingles.
Asphalt Shingle
The most common residential roofing material, consisting of a fiberglass or organic mat saturated with asphalt and coated with mineral granules for weather protection and color.
Attic Ventilation
The controlled flow of air through an attic space, using intake (soffit) and exhaust (ridge) vents to manage heat and moisture.
Building Envelope
The collection of components separating the conditioned interior from the exterior environment — roof, walls, windows, doors, insulation, air barriers, and weather-resistive barriers.
Caulking
The application of sealant to gaps and joints. A maintenance task that should be performed as sealants age and fail.
Chimney Cricket
A small, saddle-shaped roof structure built behind a chimney to divert water around the chimney rather than behind it. Required for wide chimneys.
Condensation
The process where water vapor changes to liquid water when it contacts a surface at or below the dew point temperature. A common cause of attic moisture problems.
Counterflashing
The upper piece of a two-part flashing system used at masonry walls and chimneys. Embedded in mortar joints and overlaps the base or step flashing below it.
Deck Replacement
Removing and replacing damaged or deteriorated roof decking (plywood or OSB) during a roof replacement. Necessary when the deck is rotten, delamined, or structurally compromised.
Delamination
The separation of layers in plywood or OSB decking, typically caused by moisture exposure. Compromises structural integrity and requires replacement.
Door Flashing
A system of materials installed around door openings to manage water, similar to window flashing. Sill pan flashing at the threshold is particularly critical.
Downspouts
Vertical pipes that carry water from gutters to ground level and away from the foundation. Should discharge at least several feet from the building.
Drip Edge
L-shaped metal flashing installed along roof edges (eaves and rakes) to direct water away from the roof edge and into gutters, protecting the fascia and underlayment.
Eave
The lower, horizontal edge of a roof that extends beyond the exterior wall. Where gutters are typically installed and where ice dams form.
Exhaust Ventilation
Vents that allow warm, moist attic air to exit, typically at or near the ridge. Includes ridge vents, static vents, and powered fans.
Fascia
The vertical trim board along the roof edge that gutters are typically attached to. Must be structurally sound to support the weight of loaded gutters.
Flashing
Metal or rubberized material installed at roof transitions, penetrations, and intersections to direct water away from vulnerable joints. The most critical component for preventing roof leaks.
Gable
The triangular wall section at the end of a pitched roof, from eave to ridge. Gable roofs are more susceptible to wind damage than hip roofs.
Granule Loss
The loss of the mineral granules from the surface of asphalt shingles, caused by aging, hail impact, or mechanical damage. Exposes the asphalt to UV degradation.
Gutters
Channels installed along the roof edge (eave) to collect roof runoff and direct it to downspouts, protecting the foundation and exterior from water damage.
Hail Damage
Damage to roofing and exterior materials caused by hail impact. Appears as bruises, cracks, or dents depending on the material and hail size.
Hip
The external intersection where two roof planes meet, creating a raised edge. Covered with hip caps for protection.
House Wrap
A common type of weather-resistive barrier — a thin, breathable membrane installed over wall sheathing and beneath siding to manage water and reduce air infiltration.
Ice & Water Barrier
A self-adhering, rubberized membrane installed in vulnerable roof areas (eaves, valleys, around penetrations) that seals around fasteners to prevent water from ice dams and wind-driven rain from reaching the deck.
Ice Dam
A ridge of ice that forms at the roof eave when snow melts on a warm roof deck and refreezes at the cold edge. Can force water backward under shingles and cause leaks.
Insulation
A material that resists heat flow, reducing heat transfer between the interior and exterior of a building. Common types include fiberglass, cellulose, and spray foam.
Intake Ventilation
Vents that allow outside air to enter the attic, typically at the soffit or eave. The foundation of the attic ventilation system.
Moss
A plant growth that can develop on roofing materials in shaded, moist environments. Moss can lift and damage shingles as it grows.
OSB
Oriented Strand Board — a wood panel made of compressed wood strands and adhesive. Commonly used as roof decking as an alternative to plywood.
Pipe Boot
A rubber or neoprene flashing that seals around plumbing vent pipes penetrating the roof. Deteriorates from UV exposure and is a common leak source.
Plumbing Vent
A pipe that extends through the roof to allow air into the plumbing system, preventing trap siphoning. Sealed at the roof with a pipe boot.
Plywood
A wood panel made of thin veneers glued together in alternating grain directions. Used as roof decking and provides structural strength.
Rake
The sloped edge of a roof that runs from the eave to the ridge at a gable end. Protected with drip edge.
Re-Roof
Installing new roofing over existing roofing without a full tear-off. Only appropriate under specific conditions and generally less preferred than a full tear-off.
Ridge
The highest horizontal line of a roof where two roof planes meet at the top. Covered with ridge caps and may include a ridge vent for exhaust ventilation.
Ridge Cap
Specially designed shingles or components installed at the roof ridge (peak) and hips to protect these high-stress, wind-exposed areas.
Ridge Vent
A continuous exhaust vent installed along the roof peak that allows warm, moist attic air to exit, working in conjunction with intake (soffit) ventilation.
Roof Deck
The structural surface (typically plywood or OSB) beneath all roofing materials. Provides the foundation for fastening the roofing system and must be sound for proper performance.
Roof Penetration
Any object that passes through the roof surface — plumbing vents, chimneys, skylights, exhaust fans. Each penetration requires proper flashing to prevent leaks.
Roof Pitch
The steepness of a roof, expressed as a ratio of vertical rise to horizontal run. Affects material selection, installation methods, and water shedding performance.
Roof Slope
Similar to pitch, expressed as inches of rise per foot of horizontal run. A 4:12 slope rises 4 inches for every 12 inches of horizontal distance.
Roofing Square
See 'Square' — 100 square feet of roofing area, the standard unit for measuring and pricing roofing materials.
Rot
Decomposition of wood caused by fungal growth in the presence of moisture. A common consequence of water intrusion in decking, fascia, and framing.
Sealant
A flexible material used to seal gaps and joints in the building envelope. Deteriorates over time and must be periodically inspected and replaced.
Siding
The exterior wall cladding material that protects the wall assembly and provides appearance. Types include vinyl, fiber-cement, engineered wood, and composite.
Skylight
A window installed in a roof surface to admit natural light. A large penetration that requires proper flashing to prevent leaks.
Soffit
The material installed beneath roof overhangs. Can be vented (perforated) to serve as intake ventilation for the attic, or solid for appearance and protection only.
Square
A unit of roofing area equal to 100 square feet. Roofing materials are typically sold by the square.
Starter Strip
A specialized shingle or roll product installed along the eave edge before the first course of field shingles. Provides a sealed, wind-resistant foundation for the first row.
Step Flashing
L-shaped pieces of metal installed in a stair-step pattern where a sloped roof meets a vertical wall. Each piece overlaps the one below to shed water away from the joint.
Tear-Off
The process of removing all existing roofing materials down to the deck. Preferred over installing over existing roofing because it allows full inspection and proper preparation.
Thermal Bridge
A path in the building envelope where heat transfers more easily than through surrounding areas, often due to structural elements that bypass insulation.
Underlayment
A protective layer installed between the roof deck and the primary roof covering (shingles). Provides a secondary moisture barrier. Types include synthetic, felt, and self-adhering membrane.
Valley
The internal intersection where two roof planes meet, creating a channel where water concentrates. Requires specialized valley flashing for water management.
Vapor Retarder
A material that limits the passage of water vapor through a building assembly. Placement depends on climate to prevent condensation within wall or roof assemblies.
Weather-Resistive Barrier
A material (like house wrap) installed over wall sheathing and beneath siding that allows water vapor to pass through while blocking liquid water. Part of a wall's water-management system.
Wind Uplift
The upward force exerted by wind on a roof surface. Roofing systems must be designed and installed to resist wind uplift through proper fastening and sealing.
Window Flashing
A system of materials installed around window openings to direct water away from the opening and into the wall's drainage plane. Includes sill, jamb, and head flashing.