Roofing Terms

Shingles manufactured with copper granules that inhibit the growth of blue-green algae, which causes dark streaks on roofs. Common in humid climates but beneficial in Colorado where moisture can collect in shaded areas.

Multi-layered asphalt shingles that create a dimensional, textured appearance. Also called laminated or dimensional shingles. They're thicker, more durable, and more wind-resistant than 3-tab shingles.

The most common residential roofing material in North America. Made of a fiberglass mat coated with asphalt and surfaced with mineral granules. Available in 3-tab and architectural styles.

The system of intake and exhaust vents that circulates air through the attic space. Proper ventilation prevents moisture buildup, ice dams, and premature shingle deterioration.

Raised bubbles on the shingle surface caused by moisture trapped in the shingle during manufacturing or by excessive heat in poorly ventilated attics.

A rubber or metal flashing fitted around plumbing vent pipes where they penetrate the roof. Boots deteriorate after 10-15 years and are a common source of roof leaks.

A flat or low-slope roofing system made of alternating layers of bitumen and reinforcing fabrics. Common on commercial buildings.

A package of shingles. Most architectural shingles require 3-4 bundles per square (100 sq ft).

The top layer of a built-up or modified bitumen roofing system that provides weather protection and UV resistance.

Flexible waterproofing material applied around flashing, penetrations, joints, seams, corners, and around windows and doors to prevent water and air infiltration. Must be compatible with materials and rated for exterior use. Must be regularly maintained and replaced as it ages.

A line snapped on the roof deck using chalk to guide straight, aligned shingle installation.

The highest impact resistance rating for roofing materials per UL 2218 testing. Class 4 shingles withstand a 2-inch steel ball dropped from 20 feet. Important in Colorado's hail-prone climate and may qualify for insurance discounts.

A valley installation method where shingles from one slope extend across the valley while the opposing shingles are cut along a chalk line. Creates a clean, defined valley line.

A metal ring installed around a pipe or vent where it penetrates the roof, directing water away from the opening.

Metal flashing embedded in masonry (chimneys, walls) that overlaps the base flashing below, creating a two-piece waterproofing system.

A single horizontal row of shingles or siding across the roof or wall.

A small peaked structure built behind a chimney or other vertical surface to divert water around it. Prevents water pooling and ice dam formation.

When shingle edges turn upward, creating a concave shape. Caused by moisture absorption on the underside or aging. Cupped shingles are vulnerable to wind damage.

The structural surface — usually plywood or OSB — attached to the rafters that forms the base layer of the roof system. All other roofing components are installed on top of the deck.

See Architectural Shingles. The terms are interchangeable.

A windowed structure that projects from a sloped roof, adding headroom, light, and ventilation. Dormers create complex flashing details that require careful installation.

The vertical pipe that carries rainwater from the gutter down to the ground or drainage system.

An L-shaped metal strip installed along the eaves and rakes of a roof. It directs water into the gutter and prevents it from wicking back under the shingles.

The horizontal lower edge of a roof that overhangs the exterior wall. Ice dams commonly form along the eaves. Siding terminates at or just below the eave line.

The portion of a shingle or siding that is visible and exposed to weather after installation. For shingles, typically 5 to 5-5/8 inches. For siding, it is the width not overlapped by the course above.

The vertical board mounted along the eave edge of the roof where gutters are attached. Protects the rafter tails from weather. Siding often terminates at the fascia.

See Underlayment. Traditional roofing felt is an asphalt-saturated paper used as a moisture barrier between the deck and shingles. Largely replaced by synthetic underlayment.

Thin metal (aluminum, copper, or galvanized steel) or membrane installed at joints, transitions, penetrations, and around windows and doors to prevent water entry. Critical around chimneys, skylights, walls, valleys, vents, and where siding meets other surfaces.

The triangular wall section between the edges of intersecting roof slopes. Often sided with a different material or pattern for architectural interest.

A vent installed in the gable end wall to allow air circulation in the attic. Part of the attic ventilation system.

North America's largest roofing manufacturer. Makes Timberline shingles and a complete line of roofing system components.

Crushed rock or minerals embedded in the surface of asphalt shingles. Granules provide color, UV protection, and fire resistance. Granule loss is a sign of shingle aging or hail damage.

A channel mounted along the eave that collects rainwater and directs it to downspouts. Proper gutter function is essential to protecting the roof, siding, and foundation.

Damage to roofing materials caused by hailstone impact. Appears as dents, cracks, bruises, or granule loss on shingles and dents on metal components. Denver averages 7-9 significant hailstorms per year.

The external angle formed where two sloping roof surfaces meet. Hip roofs have four sloped sides and no gable ends.

Specially cut or manufactured shingles installed along the hip of a roof.

A self-adhesive waterproof membrane installed on the roof deck in vulnerable areas — eaves, valleys, around penetrations, and low-slope sections. Required by code in cold climates. Also called ice and water barrier.

A ridge of ice that forms along the eave when snow melts on the upper roof, flows down, and refreezes at the colder eave edge. Ice dams force water underneath shingles, causing leaks. Common in Colorado's freeze-thaw climate.

Shingles rated Class 3 or Class 4 for hail resistance. Many Colorado insurance companies offer premium discounts for Class 4 roofs.

A small piece of flashing installed where a roof edge meets a sidewall, directing water into the gutter instead of behind the siding. Prevents serious hidden water damage.

See Architectural Shingles.

Water infiltrating through the roof system into the building interior. Leaks can occur at any penetration, joint, or area of damage. The visible drip or stain is often far from the actual entry point.

A roof with a pitch less than 3:12 (3 inches of rise per 12 inches of run). Requires different materials and installation methods than steep-slope roofs.

Roofing made from steel, aluminum, copper, or zinc panels or shingles. Extremely durable (40-70+ year lifespan), lightweight, fire-resistant, and energy-efficient.

A type of flat or low-slope roofing material made from asphalt modified with rubber or plastic polymers for improved flexibility and durability.

When a roofing nail works its way up through the shingle, creating a raised bump. Nail pops break the shingle seal and can cause leaks.

A valley installation where metal flashing is visible in the center of the valley with shingles trimmed back on both sides. Allows high water volumes to flow freely.

Engineered wood panel used as roof decking. Made from compressed wood strands bonded with adhesive. An alternative to plywood.

The portion of the roof that extends beyond the exterior wall. Protects the wall and foundation from water runoff.

Any object that passes through the roof surface — plumbing vents, HVAC ducts, chimneys, skylights. Every penetration requires proper flashing.

The steepness of a roof, expressed as a ratio of vertical rise to horizontal run (e.g., 6:12 means 6 inches of rise per 12 inches of run). Affects material choices, installation methods, and cost.

Layered wood panel used as roof decking. Generally considered stronger than OSB for roofing applications.

A structural framing member that runs from the ridge to the eave, supporting the roof deck.

The sloped edge of a roof along the gable end.

Installing a new roof. Can mean either a tear-off (removing old shingles first) or an overlay (installing new shingles over existing).

The highest horizontal line of the roof where two sloped surfaces meet.

Shingles specifically designed or cut to cover the ridge of the roof. Ridge caps are vulnerable to wind damage.

A continuous vent installed along the roof ridge that allows warm, moist air to exhaust from the attic. Works with soffit vents to create balanced attic ventilation.

The complete assembly of components that make up a functioning roof: deck, underlayment, ice and water shield, drip edge, shingles, flashing, ventilation, and ridge caps.

See Cricket.

A factory-applied adhesive strip on shingles that bonds to the shingle above when activated by heat, creating a wind-resistant seal.

The structural panel (plywood or OSB) attached to the roof rafters or wall studs that provides a base for roofing or siding installation. For roofing, see Deck/Decking. For siding, it provides a nailing surface and structural bracing.

See Pitch.

The underside of the roof overhang. Soffits typically contain ventilation openings (soffit vents) that allow outside air to enter the attic. Can be vented or solid, and are typically made of aluminum, vinyl, or fiber cement.

Openings in the soffit that allow fresh air to enter the attic, working with ridge or exhaust vents to maintain proper airflow.

A unit of measurement for roofing equal to 100 square feet. A typical home has 20-35 squares of roofing.

A type of metal roofing where panels are joined by raised seams that interlock. No exposed fasteners, creating a clean look and superior weather resistance.

For roofing, a row of shingles or a purpose-made starter product installed along the eave before the first course of shingles, providing adhesive and wind uplift protection. For siding, a narrow strip installed at the bottom of the wall that locks the first panel in place and sets the correct angle.

Individual pieces of L-shaped flashing installed at each shingle course where the roof meets a vertical wall. Each piece overlaps the one below, creating a shingle-like waterproofing pattern.

Steel roofing panels coated with stone granules to mimic the appearance of traditional materials (tile, shake, shingles) while offering the durability and weight savings of metal.

Roof damage caused by severe weather — hail, high winds, heavy rain, fallen trees, or lightning. Most storm damage is covered by homeowner's insurance.

A lightweight, tear-resistant polymer-based underlayment that has largely replaced traditional felt paper. Offers better protection, lies flatter, and is safer to walk on during installation.

The process of removing all existing roofing materials down to the deck before installing a new roof. Allows inspection of the deck for damage and ensures a clean substrate for the new system.

Single-layer asphalt shingles with cutouts (tabs) that create a flat, uniform appearance. Less expensive than architectural shingles but also less durable, less wind-resistant, and shorter-lived.

GAF's most popular line of architectural shingles, including Timberline HDZ (high-definition with LayerLock technology) and Timberline UHDZ (ultra-high definition).

A pre-fabricated triangular structural framework that supports the roof. Trusses span the width of the building and eliminate the need for interior load-bearing walls.

A water-resistant or waterproof barrier installed on the roof deck beneath the shingles. Provides secondary weather protection if shingles are damaged or displaced. For siding, see House Wrap.

The internal angle where two sloping roof surfaces meet, creating a channel that concentrates water flow. Valleys require special flashing and installation techniques.

See Attic Ventilation.

A valley installation where shingles from both slopes are interlaced (woven) across the valley center. Creates a continuous shingle appearance with no exposed metal.