Roofing Terminology Glossary

Browse Roofing Terminology

[A-B] [C-F] [G-I] [J-L] [M-O] [P-R] [S-U] [V-X] [Y-Z]

A

Aggregate
A surfacing or ballast for a roof system. Aggregate can be rock, stone, crushed stone or slag, water-worn gravel, crushed lava rock or marble chips.

Algae Discoloration
A type of roof discoloration caused by algae. Commonly called fungus growth.

Alligatoring
The cracking of the surfacing bitumen on a built-up roof because of the limited tolerance of asphalt to thermal expansion or contraction, producing a pattern of cracks that resemble an alligator’s hide.

Attic
The open area above the ceiling and under the roof deck of a steep-sloped roof.

B

Back Surfacing
Fine mineral matter applied to the back side of shingles to keep them from sticking.

Base Flashing
That portion of the flashing attached to or resting on the deck to direct the flow of water onto the roof covering.

Battens
1″x2″x4′ wood strips nailed to the roof, upon which the field tile hangs.

Bird Stop
In addition to preventing birds from nesting in the hollows of the tile, this length of formed metal or foam elevates the first course of tile so that it is positioned at the same angle as subsequent courses.

Blisters
Bubbles that may appear on the surface of asphalt roofing after installation.

Built-Up Roof
An outer covering of a comparatively flat roof, consisting of several layers of saturated felt. As laid, each layer is mopped with hot tar or asphalt. The top layer is finished with a mineral or rock covering and a special coating.

Bundle
A package of shingles. There are 3, 4 or 5 bundles per square.

Butt and Run
The installation of a new roof system over an existing system without removing an existing system.

Butt Edge
The lower edge of the shingle tabs.

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Cap
Shingles used to cover the inclined external angle formed by the intersection of two sloping roof planes.

Caulk
To fill a joint with mastic or asphalt cement to prevent leaks.

Chalk Line
A line made on the roof by snapping a taut string or cord dusted with chalk. Used for alignment purposes.

Class “A”
The highest fire-resistance rating for roofing as per ASTM E-108. Indicates roofing is able to withstand severe exposure to fire originating from sources outside the building.

Class “B”
Fire-resistance rating that indicates roofing materials are able to withstand moderate exposure to fire originating from sources outside the building.

Class “C”
Fire-resistance rating that indicates roofing materials are able to withstand light exposure to fire originating from sources outside the building.

Closed Cut Valley
A method of valley treatment in which shingles from one side of the valley extend across the valley while shingles from the other side are trimmed two inches from the valley centerline. The valley flashing is not exposed.

Coating
A layer of viscous asphalt applied to the base material into which granules or other surfacing is embedded.

Collar
Pre-formed flange placed over a vent pipe to seal the roof around the vent pipe opening. The collar is also called a vent sleeve.

Color-Through
During manufacturing, the color is mixed throughout the roofing material to become an integral part of it. When the product is cut, the affected area shows the same color as the surface.

Concealed Nail Method
Application of roll roofing in which all nails are driven into the underlying course of roofing and covered by a cemented, overlapping course. Nails are not exposed to the weather.

Condensation
The change of water from vapor to liquid when warm, moisture-laden air comes in contact with a cold surface.

Counter Flashing
That portion of the flashing attached to a vertical surface to prevent water from migrating behind the base flashing.

Course
A row of shingles or roll roofing running the length of the roof.

Coverage
Amount of weather protection provided by the roofing material. Depends on number of layers of material between the exposed surface of the roofing and the deck; i.e., single coverage, double coverage, etc.

Cricket
A peaked saddle construction at the back of a chimney to prevent accumulation of snow and ice and to deflect water around the chimney.

Cutout
The open portions of a strip shingle between the tabs.

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Deck or Decking
The structural “skin” of a roof over which roofing in applied. Most new homes have decking made of plywood.

Dormer
A framed window unit that projects through the sloping plane of a roof.

Double Coverage
Application of asphalt roofing such that the lapped portion is at least two inches wider than the exposed portion, resulting in two layers of roofing material over the deck.

Downspout
A pipe for draining water from roof gutters. Also called a leader.

Drip Edge
A non-corrosive, non-staining material used along the eaves and rakes to allow water run-off to drip clear of underlying construction.

Dutch Lap Method
Application of giant individual shingles with the long dimension parallel to the eaves. Shingles are applied to overlap adjacent shingles in each course as well as the course below.

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Eaves
The horizontal, lower edge of a sloped roof.

Eaves Flashing
Additional layer of roofing material applied at the eaves to help prevent damage from water back-up.

Edging Strips
Boards nailed along eaves and rakes after cutting back existing wood shingles to provide secure edges for re-roofing with asphalt shingles.

Edge Venting
The installation of a vent material along the roof edge (e.g., Starter Vent) as part of a ventilation system. Edge vent material should be used in conjunction with other venting material (e.g., ridge vent) as it not intended for use by itself.

EPDM
These roofing systems are made from large sheets of synthetic rubber that are placed on the roof and seamed in place using adhesives or special tapes. The roof is complete in a single layer; thereby the term single-ply.

Exposed Nail Method
Application of roll roofing in which all nails are driven into the cemented, overlapping course of roofing. Nails are exposed to the weather. This is a very poor quality application and Adept Roofing never use this method.

Exposure
Portion of the shingle exposed to the weather. Exposure is measured from the butt of one shingle to the butt of the next.

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Fascia
Horizontal trim at the eaves that covers the rafter ends.

Feathering Strips
Tapered wood filler strips placed along the butts of old wood shingles to create a level surface when re-roofing over existing wood shingle roofs. Also called horse feathers.

Felt
A flexible sheet that is saturated with asphalt and used as an underlayment, sometimes called “tar paper”

Fiber-Cement
A roofing material that has cellulose (wood fiber) mixed into it. Cellulose absorbs water and can add greatly to the roof’s weight, while reducing its longevity.

Fiberglass Mat
An asphalt roofing base material manufactured from glass fibers.

Flashing
Pieces of metal or roll roofing used to prevent seepage of water into a building around any intersection or projection in a roof such as vent pipes, chimneys, adjoining walls, dormers and valleys. Galvanized metal flashing should be minimum 26-gauge.

Flashing Cement
An asphalt-based cement used to bond roofing materials. Also known as mastic.

Free-Tab Shingles
Shingles that do not contain factory-applied strips or spots of self-sealing adhesive.

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Gable
The upper portion of a sidewall that comes to a triangular point at the ridge of a sloping roof.

Gable Roof
A type of roof containing sloping planes of the same pitch on each side of the ridge. Contains a gable at each end.

Gambrel Roof
A type of roof containing two sloping planes of different pitch on each side of the ridge. The lower plane has a steeper slope than the upper. Contains a gable at each end.

Geocel
Geocel Corporation is a Manufacturer of Quality Sealants, Caulks, and Adhesives Designed for Tough Construction and Repair Applications.

Granules
Ceramic-coated colored crushed rock that is applied to the exposed surface of asphalt roofing products.

Gutter
The trough that channels water from the eaves to the downspouts.

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HEX Shingles
Shingles that have the appearance of a hexagon after installation.

Hip
The inclined external angle formed by the intersection of two sloping roof planes. Runs from the ridge to the eaves.

Hip Roof
A type of roof containing sloping planes of the same pitch on each of four sides. Contains no gables.

Hip Shingles
Shingles used to cover the inclined external angle formed by the intersection of two sloping roof planes.

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Ice Dam
Ice dams occur when snow melts near the ridge lines of warm roofs (roofs without adequate ventilation). As the water runs down the roof to the overhang, it cools and freezes. If the snow continues this melt and freeze process, an ice dam can form that can seep under the shingles, through the decking and into the house. This, of course, can cause serious roof leaks–even in freezing temperatures.

The best prevention to ice dams is a well-ventilated (cool) roof. Additional protection for your roof can be applied with an impermeable ice and water membrane. The membrane is installed on top of the decking, under the roofing material. Temporary prevention of ice dams can also be done through the use of electric cables along the eaves of the roof (where the dams usually form). However, new ice dams can form above the cables and still cause extensive damage.

Another emergency solution to ice dams is to fill a sock or nylon with calcium chloride. Lay the stocking vertically across the ice dam. The calcium chloride will melt the ice and release the water so that it can drain outside, and not inside your roof.

Ice and Water Shield
A rubberized asphalt product backed with a release paper that protects its adhesive quality. During application, the release paper is removed, allowing the rubberized asphalt to bond tightly to the roof deck. Used to to protect decking from water damage caused my water backing up under the shingles from ice damming. In many states the application of this product is required by code.

Intake Ventilation
The part of a ventilation system used to draw fresh air in. Usually vents installed in the soffit or along the eaves of a building.

Interlocking Shingles
Individual shingles that mechanically fasten to each other to provide wind resistance.

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Joists
Any of the small timbers or metal beams ranged parallel from wall to wall in a structure to support a floor or ceiling.

K

L

Laminated Shingles
Strip shingles containing more than one layer of tabs to create extra thickness. Also called three-dimensional shingles.

Lap
To cover the surface of one shingle or roll with another.

Lap Cement
An asphalt-based cement used to adhere overlapping plies of roll roofing.

Lean-to Roof
A roof with one slope only that is built against a higher wall.

Life-cycle Cost
The total lifetime cost of a roof. Calculated by adding maintenance costs to the installed price, then deducting the added value the roof provides when the home is resold.

Low Slope Application
Method of installing asphalt shingles on roof slopes between two and four inches per foot.

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Mansard Roof
A type of roof containing two sloping planes of different pitch on each of four sides. The lower plane has a much steeper pitch than the upper, often approaching vertical. Contains no gables.

Mastic
An asphalt-based cement used to bond roofing materials. Also known as flashing cement.

Metal Drip Edge
A narrow strip of non-corrodible metal used at the rake and eave to facilitate water runoff.

Mineral-surfaced Roofing
Asphalt shingles and roll roofing that are covered with granules.

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Nesting
A method of re-roofing with new asphalt shingles over old shingles in which the top edge of the new shingle is butted against the bottom edge of the existing shingle tab.

New Construction
Installing a roof system on new construction.

No-cutout Shingles
Shingles consisting of a single, solid tab with no cutouts.

Non-prorated Warranty
A warranty which provides full replacement costs for the item(s) covered during the full term of the warranty. In contrast, a prorated warranty merely reimburses a percentage of replacement costs, depending on the age of the roof.

Non-veneer Panel
Any wood based panel that does not contain veneer and carries an APA span rating, such as wafer board or oriented strand board.

Normal Slope Application
Method of installing asphalt shingles on roof slopes between 4 inches and 21 inches per foot.

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Open Valley
Method of valley construction in which shingles on both sides of the valley are trimmed along a chalk line snapped on each side of the valley. Shingles do not extend across the valley. Valley flashing is exposed.

Organic Felt
An asphalt roofing base material manufactured from cellulose fibers.

Organic Shingle
An asphalt shingle reinforced with organic material manufactured from cellulose fibers.

Overhang
That portion of the roof structure that extends beyond the exterior walls of a building.

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Pallets
Wooden platforms used for storing and shipping bundles of shingles.

Parapet
A low protective wall that extends above the roof line or balcony for support.

Pitch
The degree of roof incline expressed as the ratio of the rise, in feet, to the span, in feet.

Plastic Cement
A compound used to seal flashings and in some cases to seal down shingles as well as for other small waterproofing jobs. Where plastic cement is required for sealing down shingles, use a dab about the size of a half dollar unless otherwise specified.

Ply
The number of layers of roofing: i.e. one-ply, two-ply.

Plywood
A type of engineered board made from thin sheets of wood , called plies or wood veneers. The layers are glued together, each with its grain at right angles to adjacent layers for greater strength. There are usually an odd number of plies, as the symmetry makes the board less prone to warping [1], and the grain on the outside surfaces runs in the same direction. The plies are bonded under heat and pressure with strong adhesives, usually phenol formaldehyde resin, [2] making plywood a type of composite material. Plywood is sometimes called the original engineered wood.[3] The adhesives used in plywood has become a point of concern, due to the off gassing of the formaldehyde. Both urea formaldehyde and phenol formaldehyde are carcinogenic, so their use undesirable. Many manufacturers are turning to “Greener Products” as government regulations become stronger against the use of these adhesives. [4] A common reason for using plywood instead of plain wood is its resistance to cracking, shrinkage, twisting/warping, and its general high degree of strength. It has replaced many dimensional lumbers on construction applications for these reasons.

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R

Racking
Roofing application method in which shingle courses are applied vertically up the roof rather than across and up. Not a recommended procedure.

Rafter
The supporting framing member immediately beneath the deck, sloping from the ridge to the wall plate.

Rake
The inclined edge of a sloped roof over a wall from the eave to the ridge.

Random-tab Shingles
Shingles on which tabs vary in size and exposure.

Release Tape
A plastic or paper strip that is applied to the back of self-sealing shingles. This strip prevents the shingles from sticking together in the bundles, and need not be removed for application.

Re-cover (overlay)
The installation of a new roof system over an existing system without removing an existing system.

Re-roofing
Installing a new roof system on a building that is not new.

Ridge
The uppermost, horizontal external angle formed by the intersection of two sloping roof planes.

Ridge Shingles
Shingles used to cover the horizontal external angle formed by the intersection of two sloping roof planes.

Ridge Vent
A type of vent installed at the peak of a sloped roof which allows warm, humid air to escape a building’s attic. Ridge vents are most common on shingled residential buildings.

Rise
The vertical distance from the eaves line to the ridge.

Roll Roofing
Asphalt roofing products manufactured in roll form.

Roofing Tape
An asphalt-saturated tape used with asphalt cements for flashing and patching asphalt roofing.

Run
The horizontal distance from the eaves to a point directly under the ridge. One half the span.

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Saturant
Asphalt used to impregnate an organic felt base material.

Self-sealing Shingles
Shingles containing factory-applied strips or spots a thermal sealing tab cement to firmly cement the shingles together automatically after they have been applied properly and exposed to warm sun temperatures. In warm seasons, the seal will be complete in a matter of days. In colder seasons, sealing time depends on the temperature and amount of direct sunlight hitting the shingles. Hand sealing with plastic cement should be done to ensure sealing in winter.

Self-sealing Strip or Spot
Factory-applied adhesive that bonds shingle courses together when exposed to the heat of the sun after application. Also known as self-sealing cement.

Selvage
That portion of roll roofing overlapped by the succeeding course to obtain double coverage.

Shading
Slight differences in shingle color that may occur as a result of normal manufacturing operations.

Sheathing
Exterior grade boards used as a roof deck material.

Shed Roof
A roof containing only one sloping plane. Has no hips, ridges, valleys or gables.

Single Coverage
Asphalt roofing that provides one layer of roofing material over the deck.

Slope
The degree of roof incline expressed as the ratio of the rise, in inches, to the run, in feet.

Smooth-surfaced Roofing
Roll roofing that is covered with ground talc or mica instead of granules (coated).

Soffit
The finished underside of the eaves.

Soil Stack
A vent pipe that penetrates the roof.

Span
The horizontal distance from eaves to eaves.

Specialty Eaves Flashing Membrane
A self-adhering, waterproofing shingle underlayment designed to protect against water infiltration due to ice dams or wind-driven rain.

Square
A unit of roof measure covering 100 square feet.

Square-tab Shingles
Shingles on which tabs are all the same size and exposure.

Starter Strip
Asphalt roofing applied at the eaves that provides protection by filling in the spaces under the cutouts and joints of the first course of shingles.

Steep Slope Application
Method of installing asphalt shingles on roof slopes greater than 21 inches per foot.

Step Flashing
Flashing application method used where a vertical surface meets a sloping roof plane.

Strip Shingles
Asphalt shingles that are approximately three times as long as they are wide.

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Tab
The exposed portion of strip shingles defined by cutouts.

Tar Paper
See “Felt”

Tear Off
Removing an existing roof system.

Telegraphing
A shingle distortion that may arise when a new roof is applied over an uneven surface.

Three-dimensional Shingles
See laminated shingles.

Three-tab Shingle
The most popular type of asphalt shingle usually 12″ x 36″ in size with three tabs.

Torchdown
Similar to tar and gravel roofing, the torch down roof consists of layers of fiberglass and polyester with bitumen that are added to the regular tar and gravel layering system. These extra sheets are torched down in the overlap areas during the installation process, using large flame throwing torches that melt the asphalt at the seams to join them together, which is the origin of the name “torch down roofing”. The final result is the vulcanization of a large rubber sheet onto a fiberglass base.

Top Lap
That portion of the roofing covered by the succeeding course after installation.

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UL
Underwriters Laboratories, Inc.

UL Label
Label displayed on packaging to indicate the level of fire and/or wind resistance of asphalt roofing.

Underlayment
A layer of asphalt saturated (sometimes referred to as tar paper) which is laid down on a bare deck before shingles are installed to provide additional protection for the deck.

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Valley
The internal angle formed by the intersection of two sloping roof planes to provide water runoff.

Vent
Any outlet for air that protrudes through the roof deck such as a pipe or stack. Any device installed on the roof, gable or soffit for the purpose of ventilating the underside of the roof deck.

Vent Sleeve
See collar.

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Woven Valley
Method of valley construction in which shingles from both sides of the valley extend across the valley and are woven together by overlapping alternate courses as they are applied. The valley flashing is not exposed.

X

Y

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