Roofing Services Glossary

Customers often have questions about the terminology commonly used in the roofing industry and by roofing companies. Here we will share some definitions of the terms you may frequently hear when discussing your roof installation, roof repair, roof replacement, or other roofing services projects with our team. We always aim to communicate clearly and in a way that’s easily understood, but we’re just leaving these definitions here for easy access. We hope they’re helpful! And if you find that the term you’re looking for isn’t below, please contact us and let us know!

A

ARMA: The Asphalt Roofing Manufacturers Association, a trade organization

ASTM International: a voluntary organization that establishes consensus standards, testing procedures, and specifications

Asphalt: a petroleum-based waterproofing material used in roofing products such as shingles and roofing systems.

Asphalt Shingles: commonly used, cost-effective roofing material composed of a waterproof, fiberglass or organic base that is coated in asphalt and protective ceramic granules–available in basic 3-tab, architectural, and luxury styles

Architectural Shingles: shingles that include many layers for a stronger material that has more dimension and visual depth (AKA laminated shingles)

‍B

Base Flashing: section of flashing between vertical elements and the roof itself that rests on the roof deck and directs water down onto the roof material

Bundle: a package of shingles - for standard asphalt shingles, three bundles typically equal one roofing square (100 square feet), with each bundle covering approximately 33 square feet.

Butt Edge: The lower portion of the shingle tabs that is exposed to the weather

‍C

Claim: a request filed with a policyholder’s insurance company for financial assistance to repair or replace a damaged roof

Class "A/B/C" Fire Rating: fire test classifications for roofing as per ASTM E108 or UL790, indicating that the roofing can withstand severe, moderate, or light exposure to fire

Class 4 Impact Resistance: highest impact resistance classification according to UL 2218 that can withstand hail impact without cracking

Clipped Gable: hybrid roof design that combines a standard gable roof with a small hip (sloped) section at the top of the gable end; ideal way to add architectural detail and showcase designer asphalt shingles

Condensation: conversion of water vapor into liquid where surfaces of differing temperatures meet

Counter Flashing: piece of flashing attached to a vertical surface and overlapping the base flashing to direct water away from structural elements and onto the roof surface

Course: one row of shingles running horizontally along a roof

Cricket: peaked saddle construction placed behind a chimney that redirects water away and so prevents snow and ice from piling up against the brick

D

Decking: exterior grade plywood or exterior grade OSB (per local building codes) that serves as the surface over the roof’s supporting framing to which roofing materials are applied; also called sheathing

Dormer: a window that projects vertically through the sloping section of a roof, typically as a smaller roof projection from the main roof

Drip Edge: corrosion-resistant, metal flashing that sits at the edge of the roof and functions to keep water away from the fascia board, allows for water runoff into gutters, and prevents water from seeping under roofing material

Dutch Gable: style of roof that combines a gable and hip roof for increased attic space

‍E

Eaves: the horizontal, lower edge of a roof that meets or overhangs a building’s walls

Estimate: a general cost for roofing services that includes materials, labor, and roofing companies’ profit margin–estimates are typically accurate but can shift due to fluctuating material costs and other factors

F

Fascia: vertical board along the bottom edge of the roof, typically where gutters attach

Fiberglass Mat: the woven glass-fiber mat that serves as the structural core of asphalt shingles, giving them strength, flexibility, and tear resistance

Flashing: pieces of metal used to prevent water seepage into a building around any intersection or projection on a roof, such as vent pipes, chimneys, adjoining walls, dormers, and valleys

‍G

Gable: upper triangular end portion of a roof that comes to a point at the ridge

Gable Roof: simple, two-sided roof with gables at either end; a standard gable roof is the most common type of roof, with Clipped Gable and Dutch Gable being common variations

Gambrel Roof: roof reminiscent of a barn roof, with two sloping planes of different pitches on each long side and a gable at each end

Granules: ceramic-coated, colored crushed rock (basalt, slate) on asphalt shingles that protect the asphalt from UV rays, add color, provide fire resistance, and aid in water shedding; sometimes referred to as “grit” 

‍H

Head Lap: the portion of a shingle that overlaps the shingle two courses below it - proper head lap ensures water sheds properly and helps prevent wind-driven rain infiltration.

Hip: inclined external angle of each of the four roof planes that extends from the ridge to the eaves

Hip Roof: type of roof without gables–sloping planes stretch from the ridge to the eaves on all four sides

‍I

Ice Dam: when snow on a roof overhang melts, re-freezes, and creates a barrier for water flow, causing water to back up and be forced under shingles

Ice & Water Shield: waterproof membrane used as roof underlayment on overhangs and other vulnerable roof areas to prevent ice dams and protect against ice and water damage

‍M

Mansard Roof: French style of roof that features two different sloping planes on each of its four sides, with the lower plane having a steeper pitch than the upper plane; allows for full use of the upper story, ample interior attic space, and multiple windows

Mineral Stabilizers: finely ground, inorganic materials (e.g. limestone, silica, slate) that are added to asphalt shingles to make them more resistant to fire and weathering‍ from UV rays

O

Open Valley: roof valley construction method in which shingles don’t extend across the valley, leaving flashing exposed

Overdriven Nails: when nails are driven too deeply into roofing material, damaging shingles and causing leaks

Overhang: areas where the roof structure extends beyond a building’s exterior walls

Overlay: new asphalt shingles are installed over existing shingles; building codes typically allow a maximum of two layers, but an overlay can hide structural issues and leaks, and add excess weight (also known as a “re-roof”)

‍P

Ponding: when water pools and accumulates (48 hours or longer) in low-lying areas of a flat or low-slope roof

‍R

Rafter: angled supporting framing piece that is positioned beneath the roof deck, sloping from the ridge to the roof’s edge

Rake: inclined edge of a roofline that stretches along the “arms” of a gable, running from the ridge or peak to the eave; protects from the elements and may include trim or flashing for reinforcement 

Ridge: top horizontal line of the roof, formed by the intersection of two sloping roof planes

Ridge Shingles: angled shingles used to cover the horizontal ridge at the peak of a roof

Rise: the vertical measurement of roof slope, typically expressed as the number of inches the roof rises for every 12 inches of horizontal run (e.g., 6:12).

Run: the horizontal measurement used to calculate roof slope, typically expressed as 12 inches in standard pitch ratios (e.g., 6:12 means 6 inches of rise per 12 inches of run).

‍S

Slope: degree of roof incline or the ratio of the rise to the run, with common slopes ranging from 4:12 to 12:12 in areas with heavy snow loads or on historic buildings–roof slope of x:y means there is an “x” inch rise for every “y” inches‍ in distance

Soffit: finished, typically ventilated, underside of eaves

Span: horizontal distance between eaves

Step Flashing: base flashing in an L shape that is installed in small pieces (steps) where a vertical surface meets a sloping roof plane (chimney, siding, dormer)

‍T

Tab: three equal, distinct sections cut into the lower edge of a traditional 3-tab asphalt shingle that are visible and exposed on a finished roof

Tear Off: process of removing an existing roof down to the deck

‍U

Underdriven Nails: when nails are not flush with the shingle surface; can allow water infiltration

Underlayment: asphalt-saturated felt and other specially engineered synthetic materials that are placed beneath roofing for extra protection

‍V

Valley: angle formed by the intersection of two sloping roof planes at a low point

Vapor Retarder: material used to prevent water vapor from passing through roofing layers

Vent: either a pipe that protrudes through the roof deck or a structure installed on the ridge, gable or soffit for ventilation purposes