Roof Glossary
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Glossary of Roofing Terms for the Consumer


Algae - Rooftop fungus that can leave dark stains on roofing
Algae Discoloration - A type of roof discoloration caused by algae, commonly called fungus growth
Aluminum - A non-rusting metal used in roofing for metal roofing and the fabrication of gutter and flashing
Angled Fasteners - Roofing nails and staples driven into decks at angles not parallel to the deck
APA - American Plywood Association - tests and sets standards for all varieties of plywood used In the United States.
Apron Flashing - Metal flashing used at chimney fronts.
Asphalt - A bituminous waterproofing agent used in various types of roofing materials
Asphalt Concrete Primer - Asphalt based primer used to prepare concrete and metal for asphalt sealant
Asphalt Plastic cement - Asphalt based sealant material. meeting ASTM 04586 Type l or II. Used to seal and adhere roofing materials. Also called mastic, blackjack, roof tar and bull
ASTM - The American Society of Testing and Materials - a voluntary organization that sets standards for a Wide variety of materials. Including roofing


Back-surfacing - Granular material added to shingle's back to assist in keeping separate during delIVery and storage.
Ballast - A material Installed over the top of a roof membrane to help hold it in place Ballasts are loose laid and can consist of aggregate, or concrete pavers
Base Ply - The primary ply of roofing material in a roof system.
Base Sheet - An asphalt-Impregnated, or coated felt used as the first ply in some built-up and modified bitumen roof systems
Blistering - Bubbles In roofing materials Usually mOisture related In shingles blisters are either moisture under the material or moisture trapped inSide the material
Blow~offs - When shingles are subjected to high Winds, and are forced off a roof deck.
Buckling - When a wrinkle or nipple affects shingles or their underlayments.
Built-up Roofs (BUR) - A flat or low-sloped roof consisting or multiple layers of asphalt and ply sheets.
Bundle - A package of shingles - there are 3, 4, and 5 bundles per square.
Butt Edge - The lower edge of the shingle tabs.


Cant Strip - A triangular-shaped strip of material used to ease the transition from a horizontal plane to a vertical plane. Cant strips can be made of wood. wood fiber; perlite or other materials
Cap Sheet - A granule-surfaced membrane often used as the top ply of BUR or modified roof systems.
Caulk - To fill a joint with mastic or asphalt cement to prevent leaks
cement - See asphalt plastiC cement
Chalk Line - A line made on the roof by snapPing a taunt string or cord dusted With chalk. Used for alignment purposes.
Class "A" - The highest fire-resistance rating for roofing as per ASTM E-l08 Indicated 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 "CO - 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 shingle valley installation method where one roof plane's shingles completely cover the others The top layer is cut to match the valley lines.
Coating - A layer of VISCOUS asphalt applied to the base material into whiCh granules or other surfacing is embedded.
Coll9r - Pre-formed flange placed over a vent pipe to seal the roof around the vent pipe opening - also called a vent sleeve
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
Coping - The piece of material used to cover the top of a wall and protect it from the elements It can be constructed from metal, masonry or stone
Copper - A reddish-brown element that conducts head and electricity very well It IS also used as a primary roof material as well as a flashing component Copper turns a greenish color after being exposed to the weather for a length of time
Corrosion - When rust, rot or age negatively affect roofing metals
Counter-Flashing - The metal or siding material that IS installed over rooftop base flashing systems
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 cover, etc )
Crickets - A peaked water diverter installed behind chimneys and other large roof projections Effectively diverts water around proJections.
Cupola - A relatively small roofed structure set on the ridge of a main roof area - also known as a Crow's Nest
Cupping - When shingles are Improperly installed over an existing roof or are over-exposed, they form a curl or cup.
Curb - A raised member used to support skylights, HVAC units, exhaust fans, hatches or other pieces of mechanical equipment above the level of the roof surface, and should be a minimum of eight inches in height
Cutout - The open portions of a strip shingle between the tabs.


Deck - The substrate over which roofing is applied. Usually plywood, wood boards, or planks.
Dormer - A raised roof extending out of a larger roof plane
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 - An Installed lip that keeps shingles up off of the deck at edges, and extends shingles out over eaves and gutters, and prevents water from backing up under shingles
Dry..ln - The process of Installing the underlayment In steep slope roofing making a low-slope roof watertight


Dry Rot - Wood rot caused by certain fungi Dry rot can result from condensation build-up, roof leaks that go untended, or from other problems Dry rot will not remain localized. It can spread and damage any lumber touching the affected area.


Eaves - Tile roof edge from the fascia to the structure's outside wall. In general terms, the first three feet across a roof is termed the eave
Eaves Flashing - Additional layer of roofing material applied at the eaves to help prevent damage from water backup
Edging strips - Boards nailed along eaves and rakes after cutting back existing wood shingles to provide secure edges for reproofing with asphalt shingles.
Elastomer - A material which, after being stretched, will return to its original shape
End Laps - When installing rolled products in roofing the area where a roll ends on a roof and is overlapped by the next section of rolled material. (i.e. - underlayments, rolled roofing)
Exposure - The area on any roofing material that is left exposed to the elements.
Exposure 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
Exposure I Grade Plywood - Type of plywood approved by the American Plywood Association for exterior use.


Fascia - Vertical roof trim located along the perimeter of a building, usually below the roof level.
Fasteners - Nails or staples used in securing roofing to the deck. Felt-organic or paper-based rolled material saturated with asphalt to serve as roofing underlayment
Felt - Fibrous material saturated with asphalt and used as an underlayment or sheathing paper.
FHA - The Federal Housing Authority - sets construction standards throughout the United States
Fiberglass Mat - Fibers condensed into strong, resilient mats for use in roofing materials.
Field - Refers to the central part of a roof away from the perimeter
Flange - Metal pan extending up and down a roof slope around flashing pieces Usually at chimneys and plumbing vents
Flashing - Materials used to waterproof a roof around any projections through the roof deck. 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 a minimum 26-gauge
Flashing cement - Sealant designed for use around flashing areas, typically thicker than plastic cement
FM - Factory Mutual Research Corp
Free-tab Shingles - Shingles that do not contain in factory-applied strips or spots of self-sealing adhesive.


Gable - The upper portion of a sidewall that comes to a triangular point at the ridge of a slopping roof
Gable Roof - Traditional roof style - two-peaked roof planes meeting at a ridgeline of equal size.
Galvalume - Trade name for a protective coating com posed of aluminum zinc.
Galvanize - To coat With zinc.
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 and contains a gable at each end.
Granules - Crushed rock that is coated with a ceramic coating and fired, used as top surface on shingles.
Gutter - The trough that channels water from the eaves to the downspouts.


Hand-sealing - The method to assure sealing of shingles on very steep slopes, in high wind areas, when Installing In cold weather
Head Lap - Shortest distance from the butt edge of an overlapping shingle to the upper edge of a shingle In the second courSE below The triple coverage portion of the top lap of strip shingles
HEX Shingles - Shingles that have the appearance of a hexagon after installation.
High Nailing - When shingles are nailed or fastened above the manufacturer's specified nail location
Hip - The inclined external angle formed by the intersection of two sloping roof planes Runs from the ridge to the eaves.
Hip Legs - The down-slope ridges on hip roofs.
Hip Roof - A roof with four roof planes coming together at a peak and four separate hip legs
Hip Shingles - Shingles used to cover the inclined external angle formed by the intersection of two sloping roof planes


Infrared Thermography - The use of an infrared camera to detect moisture in roof insulation.
Insulation - Materials used to help maintain a certain temperature in a building by reducing tile flow of heat to and from that building
Interlocking Shingles - IndiVidual shingles that mechanically fasten to each other to provide wind resistance.


"L" Flashing - Continuous metal flashing consisting of several feet of metal, used at horizontal walls, bent to resemble an "L"
Laminated Shingles - Shingles made from two separate pieces that are laminated together - also called dimensional or architectural shingles
laps - The area where roll roofing or rolled underlayments overlap one another during application (also see side laps and end laps)
lap cement - An asphalt-based cement used to adhere overlapping plies of roll roofing
Low Slopes - Roof pitches less than 4/12 are considered low-sloped roofs Special installation practices must be used on roof~ sloped 2/12-4/12


Mansard Roof - A roof design with a nearly vertical roof pia ne that ties into a roof plane of less-slope at its peak
Masonry Primer - An asphalt-based primer used to prepare masonry surfaces for bonding with other asphalt products
Mastic - See asphalt plastiC cement
Mats - The general term for the base material of shingles and certain rolled products.
Membrane - The portion of the roofing system that serves as the waterproofing material Can be composed of one material or several materials laminated together.
Mildew - A superficial coating or discoloration of organic materials caused by fungi, espeCially under damp conditions.
Mineral-Surfaced Roofing - Asphalt shingles and roll roofing that are covered with granules
Modified Bitumen - Rolled roofing membrane with polymer modified asphalt and either polyester or fiberglass reinforcement
Mopping - To apply hot asphalt or coat tar using a hand mop or mechanical applicator
Mortar - Mixture of sand, mortar, limestone and water used in bonding a chlmney's bricks together.


Nail Guide Line - Painted line on laminated shingles, to aid in the proper placement of fasteners
Nail Pop - When a nail is not fully driven, It sits up off the roof deck.
Nesting - Installing a second layer of shingles aligning courses with the original roof to avoid shingle cupping.
No-Cutout Shingles - Shingles consisting of a single, solid tab with no cutouts


Open Valley - Valley installation uSing metal down the valley center
Organic Mat (Felt)- Material made from recycled wood pulp and paper
Organic Shingles - Shingles made from organic (paper) mats.
OSB - Oriented Strand Board - a decking made from wood chips and lamination glues
Over Driven - The term used for fasteners driven through roofing material with too much force, breaking the material
Over Exposed - Installing shingle course higher than their intended exposure
Overhang - That portion of the roof structure that extends beyond the exterior walls of a building.


Penetration - Any object that pierces the surface of the roof.
Pitch - RatiO of the rise of the roof, in inches, to the span of the roof, In feet (I e - 4/12)
Power Vents - Electrically powered fans used to move air from attics and structures.
Plastic cement - Asphalt based sealant also called bull, mastic, tar and asphalt cement
Plumbing Vents - Term used to describe plumbing pipes that project through a roof plane, also called vent stacks.
Ply - The number of layers of roofing (ie.- one-ply, two-ply)
Ponding - The accumulation of water at low-lying areas on a roof.
Prevailing Wind - The most common direction of Wind for a particular region.


Quarter-sized - Term for the size of hand sealant dabs, the size of a U.S. 25¢ piece
Quick-Setting Cement - An asphalt-based cement used to adhere tabs of strip shingles to tile course below Also used to adhere roll roofing laps applied by the concealed nail method


Racking - Roofing application method in which shingle courses are applied vertically up the roof rather than across and up. N01 a recommended procedure.
Rafter - The supporting framing member immediately beneath the deck, sloping from the ridge to the wall plate
Rake Edge - The vertical edge of gable style roof planes
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
Ridge - The uppermost, horizontal external angle formed by the intersection of two sloping roof planes
Ridge Vent - Hard plastic ridge vent materials.
Rise - The vertical distance from the eaves line to the ridge
Roll Roofing - Asphalt roofing products manufactured in roll form.
Roof Louvers - Rooftop rectangular shaped roof vents, also called box vents, mushroom vents, air hawks and soldier vents.
Roof Plane - A roofing area defined by having four separate edges, one side of a gable, hip or mansard roof
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.


Saturated Felt - An asphalt-impregnated felt used as an underlayment between the deck and the roofing material
Self-Sealant - Sealant installed on shingles After installation, heat and sun will activate sealant to seal the shingles to each other.
Self-sealing Shingles - Shingles containing factory-applied stnps or spots for self-sealing adhesive.
Self-Sealing Strip or Spot - Factory-applied adhesive that bonds shingle courses together when exposed to the heat of the sun after application
Selvage - The non-exposed area on rolled roofing Area without granules, designed for nail placement and sealant.
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 - Roof deSign of a single roof plane Area does not tie into any other roofs
Side Laps - The area on roiled material where one roll overlaps the rolled material beneath it. Also called the selvage edge on roiled roofing
Side Wails - Where a vertical roof plane meet a vertical wall - the sides of dormers, etc.
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
Soffit Ventilation - Intake ventilation installed under the eaves, or at the roof edge
Soil Stack - A vent pipe that penetrates the roof
Span - The hOrIZontal distance from eaves to eaves
SPF(Sprayed Polyurethane Foam) Compounds - Refers to the isocyanate and resin components used to make polyurethane foam.
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 - The first course of roofing installed, usually trimmed from main roof material
Steep Slope Rooting - Generally all slopes higher than 4/12 are conSidered steep slopes A method of installing asphalt shingles on roof slopes greater than 21 inches per foot
Step Flashing - Metal-flashing pieces installed at sidewalls and chimneys for weatherproofing.
Strip Shingles - Asphalt shingles that are approximately three times as long as they are wide
Substrate - The surface that the roof is installed upon


Tab - The bottom portion of traditional shingle separated by the shingle cutouts.
Tear-offs - Removal of existing roofing materials down to the roof deck.
Telegraphing - When shingles reflect the uneven surface beneath them Shingles Installed over buckled shingles may show some buckles
Three-dimensional Shingles - See laminated shingles
Three-tab Shingles - The most popular type of asphalt shingle usually 12"x36" in size with three tabs
Top Lap - That portion of the roofing covered by the succeeding course after installation.
Transitions - When a roof plane ties into another roof plane that has a different pitch or slope


UL - Underwriters Laboratories Inc.
UL Label - Label displayed on packaging to Indicate the level of fire and/or Wind resistance of asphalt roofing
Under Drive - Term used to describe a fastener not fully driven flush to the shingles surface
Underlayments - Asphalt based rolled materials, which are designed to be installed under main roofing material, to serve as added protection


Valleys - Area where two adjOining sloped roof planes intersect on a roof creating a 'v" shaped depreSSion
Vapor - Term used to describe moisture-laden air
Vapor Retarder - Any material used to prevent the passage of water vapor.
Veneer - Any of the thin layers of wood glued together to make plywood
Vent - Any outlet for air that protrudes through the roof deck sue has a pipe or stack. Any device installed on the roof, gable or soffit for the purpose of ventilating the underside of the roof deck.
Ventilation - The term used In roofing for the passage of air from an enclosed space


Warm Wall - The finished wall inside of a structure, used In roofing to determine how to Install waterproof underlayments at eaves
Warranty - The written promise to the owner of roofing materials for material related problems
Waterproof Underlayments - Modified bitumen based roofing underlayments, which are designed to seal wood decks and waterproof critical leak areas
Weep Holes - Small holes used to permit moisture to drain that has gathered Inside a bUilding component.
Wind Clip - A clip that slips over the ends of tile, slate and other steep slope roofing materials in order to help prevent Wind uplift damage
Wind Load - The force that Wind puts on structures
Wind Uplift - The upward displacement of a section of a roof system or component caused by movement of air from a location of higher air pressure, to an area of lower air pressure Strong wind along the surface of a root especially at corners and along perimeters, creates low air pressure above the surface of the roof. Displacement or blow-off of shingles or other roofing caused by the wind.
Woven Valleys - The method of installing valleys by laying one shingle over the other up the valley center.


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