Glossary of Roofing Terms

A | B | C | D | E | F | G | H | I | J | L | M | N | O | P | Q | R | S | T | U | V | W

Term

Definition

A

Algae discolouration

A type of roof discolouration caused by algae. Commonly, but inaccurately, called fungus growth. Usually it is dark brown to black in colour.

Algae Resistant Shingles

Shingles which are coated with copper granules on the weather side to prevent the formation of algae and the resultant discolouration.

Algicidal Treatment

A method of cleaning discoloured shingles with a bleach mixture to lighten the discolouration caused by algae formation.

Alligatoring

Surface cracking due to oxidation and shrinkage stresses, which shows a repetitive mounding of an asphalt surface, resembling the hide surface, resembling the hide of an alligator.

APA

American Plywood Association.

Application Temperature

The temperature of the hot bitumen when applied on the roof that should be not more than 50°F less than the correct kettle temperature.

Architectural Shingles

Shingles that combine a rough dimensional look with natural colour blends. Usually designed to simulate or have reference to traditional wood or slate roofing. Varying in size across three dimensions. Length and width like a 3-tab shingle, but also varying in thickness, both within each shingle strip as well as in relation to other shingles around them. More randomness in form than traditional styled 3-tab shingles.

ARMA

Asphalt Roofing Manufacturers Association.

Asphalt

A dark brown to black cementitious material, solid or semi-solid in consistency, in which the predominating constituents are bitumen that occur in nature as such or are obtained as residue in refining petroleum. Canadian roofing asphalt is generally from the heavy end of petroleum distillation and can be obtained in a great range of viscosities and softening points.

Asphalt Primer

A solution of asphalt in petroleum solvent, used to prepare concrete roof decks for the application of hot asphalt. The primer lays dust and improves the adhesion of the molten as asphalt to the roof deck.

Asphalt Roof Cement

An asphalt-based cement used to bond roofing materials. Also known as flashing cement or mastic; should conform to ASTM D 4586 (Asbestos Free).

ASTM

American Society for Testing and Materials. A voluntary organization concerned with development of consensus standards, testing procedures and product specifications.

ASTM International

A voluntary organization concerned with development of consensus standards, testing procedures and specifications.

Attic

The open space between the underside of the roof sheathing and the upper side of the ceiling directly below the roof.

B

Back surfacing

Fine mineral matter applied to the back side of shingles, keeping them from sticking together when packaged in the bundles.

Base Flashing

  • The portion of the flashing that is attached to, or rests on the roof deck to direct the flow of water on the roof, or to seal against the roof deck.
  • A material applied to the base of a wall extending above a roof, as a protection for the junction of the wall and the roof. The simple principle is to turn the membrane up along the vertical surface, so that the roofing forms a large watertight tray, the only outlets from which are the roof drains to dispose of the water. Bituminous felts are usually used for bituminous roofing.

Base Sheet

A heavy sheet of felt sometimes used as the first ply in built-up and /or steep roofing.

Battens

Parallel strips of wood to which roof tiles are fastened.

Bitumen

Bitumens are mixtures of hydrocarbons of natural or pyrogeneous origin; or combinations of both, frequently accompanied by their non-metallic derivatives, which may be gaseous, liquid, or solid and which are completely soluble in carbon disulfide. In the roofing industry, the works covers both asphalt and coal tar pitch.

Blind Nailing

Shingles nailed in such a location that when the next shingle is applied, the nails of the first shingle do not show.

Blisters

The more evident and more serious blisters are structural blisters. They occur in many forms of deformation and are not confined to the exposed surface. They are caused mainly by the expansion of trapped air and water – vapour or moisture or other gases. Air and moisture trapped within the construction tend to expand during a rise in air temperature or from the heat of the sun, and this expansion causes the plies of the roofing to separate and bulge the roof surface in a balloon effect. The blisters are spongy to the touch and may occur between any of the layers of roofing felt, or between membrane and deck, or membrane and insulation.

Block Method (also known as Racking)

The method of applying shingles in vertical rows from eave to ridge rather than horizontal rows from rake to rake. This method makes shading more noticeable and can lead to improper fastening. It is also referred to as the straight up method.

Blow-off

A condition in which shingles flutter or flap up and down with the wind, tear, and finally blow off the roof entirely.

Blueberry

A term sometimes used to describe weather blisters. These are small surface blisters, which can be seen in large numbers over the entire roof area, more predominant during warm weather where roofs are exposed directly to the sun, and which are a result of natural weathering of the surface bitumen. Volatiles and water vapours in the bitumen tend to be driven off by heat, and when the gases are trapped they form small blisters. This type of blistering usually does not cause any failure during the normal life of the roof. Also sometimes called pimpling, pin blistering, rash blistering and bitumen bubbling.

Bond

Adherence between plies of felt, or between other elements of roof systems, which use bitumen or other materials as the cementing agent.

Brands

Airborne burning embers released from a fire.

Breather

A type of roof vent consisting of a hooded flanged pipe 2” to 8” in diameter, penetrating the roofing membrane to allow escape of moisture from insulation.

Bridging

A method of reproofing with metric-sized shingles.

Buckling

A formation of wrinkles or furrows across a shingle or shingles.

Built-Up Roofing

A built up roof consists of plies or layers of roofing felt bonded together on site with hot bitumen. A protective surface coating of gravel or slag is sometimes embedded in a heavy top coating of hot bitumen. It is laid down to conform to the roof deck, and to protect all angles formed by the roof deck with projecting surfaces, and forms a single-unit flexible waterproofed membrane fastened to the deck by cementing and nailing. The simple principle on flat roofs is to turn the membrane up to form a skirting or base flashing on the vertical surfaces, making a large watertight tray. The only outlets from this tray are the roof drains to dispose of the water.

Bundle

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

Butt edge

The lower edge of the shingle tabs. See Figure A.)

C

Cant Strip

A beveled support used at the intersection of the roof deck with vertical surfaces so that bends in the roofing membrane to form base flashings can be made without breaking the felts. They may be beveled strips of wood or insulation and in some cases, cement grout or lightweight concrete.

Cantilever

A self-supporting projection without external bracing, in which a beam or series of beams is supported by a downward force behind a fulcrum.

Cap Flashing

That portion of the flashing built into a vertical surface to prevent the flow of water behind the base flashing. The cap flashings overlap the base flashing. The metal flashing that caps off the top of the base flashing.

Cap Sheet

A mineral surfaced material that is used by its self or as the top layer of multiply self-adhered roof covering system.

Caulk

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

Cement Asphaltic Plastic

A mixture of asphalt, solvent and mineral stabilizer used for example to adhere flashings or to fill pan flashings.

Certificate of Compliance

A certificate indicating that shingles meet their appropriate standards.

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 or UL790. Indicates roofing is able to withstand severe exposure to fire originating from sources outside the building.

Class “B”

Fire-resistance rating that indicates roofing material is able to withstand moderate exposure to fire originating from sources outside the building.

Class “C”

Fire-resistance rating that indicates roofing material is able to withstand light exposure to fire originating from sources outside the building.

Clawing

The downward curving of the butt portion of the shingle. This creates a hump along the leading edge and a widening of the cut out. The bulge thus created is susceptible to substantial damage by wind action, hail and ice. Clawing is part of the normal aging process of shingles and is a sign of long service.

Clay Barrel Tiles

Two piece ceramic tiles.

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 22” from the valley centerlines. The valley flashing is not exposed.

Coal Tar Pitch

A bituminous material produced by distilled crude tar residue derived from the coking of coal. It is used as the waterproofing material for tar and gravel built-up roofing.

Coating Asphalt

A layer of asphalt applied to the base reinforcement 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. Also called a vent sleeve.

Colour Code Numbers

Number indicating the colour on a bundle of shingles.

Colour Variation

Slight differences in shingle appearance which may be due to variations in normal manufacturing colour blends or the mixing of colour blends during shingle application.

COM-PLY Panels

Composite panels made of wood veneer on the face and back with an inside core of compressed wood strands.

Concealed Nailing

Nailing method for application of roll roofing in such a manner as to conceal or cover all nails heads used to fasten the roofing to nailable decks. Also referred to as blind nailing.

Condensation

The change from water to vapour to liquid water, resulting from a drop in temperature of an air vapour mixture.

Conductor

A pipe for conveying rainwater from a roof gutter to a drain, or from a roof drain to a storm drain.

Coping

The cap or highest covering course of a wall, usually overhanging the wall and having a sloping top to carry off water.

Cornice

Projection at the top of a wall. Term applied to a construction under the eaves where the roof and the side wall meet. The top course, or courses of a wall when treated as a projecting crowning member.

Counter Flashing

Strips of metal, roofing, or fabric inserted and securely anchored to the reglet or attached to a vertical surface above the plane of the roof and turned down over the face flashing to protect the base flashing.

Course

Row of shingles that can/or run horizontally, diagonally or vertically and sometimes termed the run of the shingle.

Course

A horizontal 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.

Cracking

After long exposure, a fissure or fissure pattern appearing on the shingle or roofing due to weathering of asphalt.

Crazing

Surface deterioration of a shingle by the formation of a pattern of fine hairline cracks.

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.

CSA

Canadian Standards Association. Product has been certified for the Canadian market to meet the applicable standards.

Curb

A wall of wood or masonry built above the level of the roof, surrounding a roof opening such as for installation of roof fans or other equipment, an at expansion joints in the roof deck.

Cut Back

A solution of bitumen in a volatile solvent. Cut backs are used as primers, cold application cementing agents and damp proofing coatings.

Cutout

The open portions of a strip shingle between the tabs. (See Figure A.)

Cut-Out

The slot between shingle or tabs to create the distinctive 3-tab appearance.

D

Date Codes

Date of manufacture printed on bundles.

Dead Load

The total weight of all installed materials and the constant weight of a roof used to compute the strength of all supporting framing members.

Deck

The surface, installed over the supporting framing members, to which the roofing is applied.

Deck

Some forty of more roof deck types are currently in use in the construction industry.

Diagonal Method

Roofing application method in which shingles are applied diagonally up the roof.

Dormer

A separate smaller roofed structure that projects from a sloping roof to provide more space below the roof and to accommodate a vertical window.

Double Coverage

Application of asphalt roofing such that the lapped portion is at least 2” wider than the exposed portion, resulting in two layers of roofing material over the deck.

Downspout

A pipe for conveying rainwater from a roof gutter to a drain, or from a roof drain to a storm drain. Also called a rain water leader.

Drip Edge

A non-corrosive, non-staining material used along the eaves and rakes which proves an auxiliary edging which allows water run-off to drip clear of underlying construction.

Drip-Cap

A modified L-shaped flashing used along the eaves and rakes. The drip cap directs runoff water into the gutters and away from the fascia.

E

Eave

The horizontal roof overhang that extends outward and is not directly over the exterior walls or the building’s interior.

Eave Flashing

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

Eaves Trough

A gutter at the eaves of a roof for carrying off rainwater. It may be of wood or metal attached to the eaves, or built-in part of the eaves design usually lined with metal.

Ell

An extension of a building at right angles to its length.

End Lap

The amount of overlap at the end of a ply on the application of roof roofing felts.

Expansion Joint – BUR

A planned, controlled joint placed between two roof surfaces or between two sections of a built-up roof. The expansion joint allows the roof to expand without physical damage to the roof or building.

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. Also known as face nailing.

Exposure

That portion of a shingle that is exposed area or face of the shingle.

F

Face Nailing

Nailing with the nails placed in the exposed area or face of the shingle.

Fascia

A wood trim board used to hide the cut ends of the roof’s rafters and sheathing. The gutter system is usually nailed to the fascia.

Feathering Strips

Tapered wood filler strips placed along the butts of old wood shingles to create a level surface when reproofing over existing wood shingle roofs. Also called Horsefeathers.

Felt

A very general term used to describe roll roofing materials, consisting of a mat of organic or inorganic fibres saturated, unsaturated, or saturated and coated with asphalt or coal tar pitch.

Felt, Asbestos

Felt made of asbestos fibres, impregnated or impregnated and coated with asphalt.

Felt, Asphalt Saturated

Any type of felt that has been impregnated or saturated with asphalt. Sometimes referred to as merely asphalt felt, which can also mean felt impregnated and coated with asphalt.

Felt, Coated

Bitumen saturated felt that has been coated on one or both sides with bitumen by further processing. Coated felt may be used as base sheets, in some types of built-up roofing, and with mineral surfacing added as cap sheets and shingles.

Felt, No. 15

Asphalt or coal tar saturated felt weighting approximately 15 pounds per 100 square feet.

Felt, Perforated – BUR

Asphalt saturated felt perforated with small holes, which allow trapped air to escape during laying, and bitumen to enter to form a well-bonded membrane.

Felt, Rag

A type of heavy paper made principally from wood fibre, wood flour, waste paper and a small percentage of rag. It was formerly made principally of rag when first used in the manufacture of roofing materials. Rag felt is saturated or saturated and coated with bitumen to produce a variety of roofing felts, and prepared roofing.

Fibreglass mat

A reinforcing material for asphalt roofing manufactured from glass fibres.

Fibreglass Shingles

Asphalt shingles made with a fibreglass mat.

Fire Wall

Any wall built for the purpose of restricting the spread of fire in a building. Such walls of solid masonry or concrete usually divide a building from the foundations to about a metre above the roof.

Fire-Resistant

Material that is resistant to catching fire when exposed to open flame or flaming ashes.

Fishmouthing

The raising of portion of the butt edge (lower edge) of a shingle. This curved short section tapers back into the shingle. Usually, only the front part of the shingle is affected. At the end of the exposure, the shingle will be perfectly flat. Fishmouthing is often the result of moisture absorption followed by moisture evacuation in the shingle. Poor nailing such as raised nails can result in fishmouthing also.

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.

Flashing Block

A specially designed masonry block having a slot or opening into which the top edge of the roof flashing can be inserted or anchored. Also called raggle block.

Flashing cement

See Asphalt Roof Cement.

FM

Factory Mutual Research Corporation.

Free-Tab Shingles

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

FRT Plywood

Fire Retardant Treated plywood.

Fungus Stain

See Algae discolouration.

G

Gable

The upper portion of a sidewall that comes to a triangular point at the ridge of a sloping roof. (See Figure B.)

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 which has its slope broken by an obtuse angle, so that the lower slope is steeper than the upper slope. A double-sloped roof having two pitches. Usually contains a gable at either end.

Granules

Ceramic-coated coloured 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. See Eaves Trough.

H

Head Lap

According to ASTM it is the shortest distance from the butt edge of an overlapping shingle to the upper edge of the shingle two courses below it. It is the ‘triple coverage’ portion of the strip shingle system (designed to be a minimum 2” in length).

Header

The beam into which the common joists are fitted when framing around a roofing opening. The headers are placed so as to fit between two long beams or trimmers to support the joist ends.

Hexagonal 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. (See Figure B.)

Hip Roof

A roof that rises by inclined planes from all four sides of a building. The line where two adjacent sloping sides of a roof meet is called the hip. Also called a cottage roof. Contains no gables.

Hip Shingles

Shingles used to cover the inclined external angle formed by the intersection of two sloping roof planes. Sometimes called ‘hip and ridge’ shingles.

Horizontal Lines

Common term for the appearance of the “butt” end of the shingle courses and how they reference to the horizon. If the horizontal lines are “good”, they do not rise or fall to a large degree when referenced to the eaves line or the ridge line.

Horsefeathers

See Feathering Strips.

I

Ice Dam

Condition formed by the thawing and refreezing of melted snow, especially at the lower roof edge on the roof overhang and in gutters. Can cause water to pond and flow up and under shingles causing leaks.

J

Jack

A flanged metal sleeve used as part of the flashing around small items that penetrate a roof.

L

Lap

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

Lap Cement

An asphalt-based cement (conforming to ASTM D3019) used to adhere overlapping plies of roll roofing.

Lean-to-Roof

The sloping roof of a room having its rafters or supports pitched against and leaning on the adjoining wall of a building. Also known as a shed roof.

Live Road

The total weight of all installed equipment and materials and all variable weight (such as snow, ice and people) that will move across the surface. Used to compound the strength of all supporting framing members.

Lock Shingles

Shingles designed with a mechanical locking feature to provide effective wind resistance.

Low Slope Application

Method of installing asphalt shingles on roof slopes 2” – 4” per foot.

M

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.

Masonry Primer

An asphalt-based primer used to prepare masonry surfaces for bonding with other asphalt products.

Mastic

See Asphalt Roof Cement.

Membrane

A single layer covering which is normally considered to be waterproof. Normally resistant to tearing and often but not always, self-adhering. A sheathing which can come together to form a continuous barrier.

Mill Deck

A type of wood roof deck constructed from wood planks placed on edge vertically, and spiked or nailed together.

Mineral Stabilizers

Finely ground limestone, slate, trap rock or other inert materials added to asphalt coatings for durability and increased resistance to fire and weathering.

Mineral-Surfaced Roofing

Asphalt shingles and roll roofing that are covered with granules.

Mulsified Asphalt

Straight run asphalt liquefied by clay emulsifiers and water. Finely divided dust-like particles of asphalts are kept in suspension in a cold, but unsolidified state. Cementing action by solidification takes place when the water in the emulsion evaporates. Asphalt dispersed in the water.

N

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.

No-Cutout Shingles

Shingles consisting of a single, solid tab with no cutouts. Also known as a one-tab shingle.

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. (OSB)

Normal Slope Application

Method of installing asphalt shingles on roof slopes 4” – 21” per foot.

O

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

A reinforcing material for asphalt roofing manufactured from cellulose fibres.

Organic Shingles

Shingles made with a felt reinforcement are correctly designated as organic shingles. Many people call them asphalt shingles.

OSB

Non-veneer oriented strand board.

Overhang

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

Overlay Shingle

A one-piece shingle to which overlay pads, consisting of an additional layer of asphalt and granules, are applied in random patterns to simulate two-piece laminated shingles also known as built up shingles.

Oxalic Acid

A diluted water solution of oxalic acid is used to reduce rust stains.

P

Pallets

Wooden platforms used for storing and shipping bundles of shingles.

Parapet

A low wall along the edge of and surrounding a roof deck. It is generally an extension of exterior building walls and firewalls that usually extend about a meter or less above to roof.

Patterning

The formation of various geometric designs or patterns on the roof resulting from overlay – or laminated tab-type shingles applied incorrectly or from incorrect colour blends.

Pitch

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

Plastic Cement

See Asphalt roofing cement

Ply

A single layer or thickness or roofing material.

Ponding

The accumulation of water after rainfall at low-lying areas on a roof that remains wet when other parts of the roof have dried. Certain flat roofs are designed for the ponding of water to a shallow depth over the whole surface of the roof deck to aid in summer cooling and as fire protection.

Purlin

Boards laid from gable to gable on which the common rafters sit. Boards which may run horizontally or vertically across one or more roof planes where additional or directed airflow is required.

Q

Quick-Setting Cement

An asphalt based cement used to adhere tabs of strip shingles to the course below. Also used to adhere roll roofing laps applied by the concealed nail method.

R

Racking

Roofing application method in which shingle courses are applied vertically up the roof.

Rafter

The supporting framing member immediately beneath the roof deck sloping from the ridge to the wall plate. /the roof sheathing is fastened to the rafters.

Rake

The inclined edge of a sloped roof over a wall.

Random – Tab Shingles

Shingles on which tabs vary in size and exposure.

Reglet

A groove in the vertical wall adjacent to a roof surface, above the top of the base flashing into which the metal counter flashing is placed and rigidly held in place. It is either formed in concrete or consists of a metal insert or a “reglet block” of masonry.

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-roofing

The process of recovering or replacing an existing roofing system.

Ridge

The peak or highest point of a roof, hip or dormer. The horizontal line where two opposite sloping sides of a roof join at the highest point of the roof. On double-sloped gable roofs, it is sometimes called the comb.

Ridge Cap/Shingles

Formed shingles, shake or tiles, used to cover the ridge of a building.

Ripper

Basic tool for tearing off old shingles. Also called the ripping shovel, it is a long handle connected at a steep angle to a flat blade with a serrated leading edge.

Rise

The vertical distance from the eaves line to the ridge.

Roll Roofing

Any roofing material manufactured in roll form. More specifically it applies to mineral surfaced asphalt or composition roofing.

Roll Roofing – Smooth Surfaced

A type of roll roofing which is asphalt-coated on both sides with either a smooth or veined surface, finished with talc, mica or other fine mineral particles.

Roll Roofing – Wide Selvage

Asphalt coated roll roofing finished with natural or synthetic coloured mineral granules for only a part of its width, usually for 17 inches and sometimes referred to as 19 inch selvage. Sometimes also referred to as split sheet mineral surfaced felt. Also known as NIS – Nineteen inch sealed.

Roll Roofing-Granule Surfaced

Roll Roofing asphalt-coated on both sides and finished on one side with natural or synthetic coloured mineral granules. Also called mineral surfaced.

Roof Span

Distance from outer wall to opposing outer wall of a building covered with a roof.

Roofing System

The waterproof roof covering, roof insulation, vapour barrier (if used) and roof deck as an entity.

Roofing System Canopy

Inclusive of the roof framing members and any other architecture associated with the entire roof structure.

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.

S

Saturant

Asphalt used to impregnate an organic felt base material.

Saturated Felt

An asphalt impregnated felt used as an underlayment between the deck and the roofing material.

Scuffing

Damage to the shingle surface, usually the granules or top coating layer, caused by foot traffic or by placing objects on newly installed shingles.

Scupper

An outlet in the wall of a building or a parapet wall for drainage of overflow water from a floor or roof, directly to the outside. Special scupper drains connected to internal drains are also sometimes installed at roof and wall junction.

Sealant Adhesive

Applied to the face or back of shingles to hold them down in severe wind conditions.

Self-Adhered Shingle Underlayment

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

Shoe-Wraps

Wrappings for workers shoes that prevent scuffing of shingles.

Side Lap

The horizontal distance one shingle overlaps adjacent shingle in the same course. Also the horizontal distance one sheet of roofing overlaps adjacent sheets.

Sight Card

Cardboard geometrical shape used to determine roof slope from the ground.

Sit-Upons

Carpet or foam rubber pieces that roofers kneel or sit on while working to avoid scuffing shingles in hot weather.

Sky Light

Glazed opening in a roof to admit outside light.

Slope

The degree of roof incline expressed as the ration of the rise, in inches, to the run in inches or feet. Sometimes expressed as “pitch” in degrees of an angle.

Soffit

A board or sheet that extends from the fascia to the buildings siding and hides the bottom of an overhang. Soffit can be made from wood, vinyl plastic, sheet metal, aluminum or other materials. Soffit may or may not contain ventilation slots depending on the attic system used.

Soffit Vents

Vents located under the eaves provide air intake. They should be used together with other higher elevation vents.

Stabilized Asphalt Coating

A tough asphalt material used to coat the impregnated felt of the asphalt shingle. Also used as the only waterproofing in a fibreglass shingle. See also: Saturant.

Standard-slope application

Method of installing asphalt shingles on roof slopes between 4” and 21” per foot.

Starter Strip/Course

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. It also provides for sealing down of tabs of the first course of self-sealing shingles.

Step Flashing

Base flashing application method used where a vertical surface meets a sloping roof plane. Utilizes multiple pieces of flashing material inserted integrally with each course of roof shingles.

Stickering

The process of inserting spacers between deck panels before installation in order to allow them to reach a more natural moisture content and dimension.

Strip Shingles

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

T

Tab Cement

An asphalt-based cement used to adhere tabs of strip shingles to the courses below. A type of asphalt roofing cement often supplied in tubes.

Tabbing

Method of applying high strength adhesives to improve wind resistance of shingles.

Tear Resistance

The industry accepted method for comparing shingle toughness is the ASTM D3362 performance standard for fibreglass shingles. All of Certainteeds’ shingles meet the tear resistance requirements of ASTM 3462.

Truss

A combination of members such as beams, bars and ties, usually arranged in triangular units to form a rigid framework for supporting loads over relatively long spans as in wide span roof construction.

Tuck Pointing

Mason term used for describing the act of placing mortar into a joint with the use of a pointed trowel. Usually done during a repair of an item like a chimney.

U

UL

Underwriters Laboratories, Inc.

UL Label

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

Underlayment

Asphalt saturated felt used beneath roofing to provide additional protection for the deck.

V

Valley

The internal angle formed by the intersection of two sloping roof planes.

Vapour Barrier

A material that prevents the passage of water or water vapour through it. Vinyl, plastic, aluminum foil, kraft paper, asphalt felt, asbestos felt and a laminated combination of these materials are considered vapour barrier materials.

Vapour Retarder

Any material used to prevent the passage of water vapour.

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 Sleeves

Sheet metal flanged collars placed around vent pipes for the purpose of sealing off the roofing around the vent pipe openings.

Ventilators

Devices installed on the roof for the purpose of ventilating the interior of the building. Frequently combined with motorized fan equipment mounted on the roof, to provide positive airflow.

Viscosity

Property of a fluid that resists internal flow by releasing counter-acting forces. Viscous materials are glutinous adhesive and sticky.

W

Water Vapour

Moisture existing as a gas in air. Warm air can hold more water vapour than cold air. Water vapour in the air creates a pressure much like any other gas. Cold air has relatively low vapour pressure but warm air with larger amounts of water vapour has a greater pressure. The difference in pressures cause the vapour to do strange things such as penetrating building materials in the direction from high to low vapour pressure.

Waterproofing shingle underlayment

A special self-adhering waterproofing shingle underlayment designed to protect against water infiltration due to ice dams or wind-driven rain.

WB

Non-veneer wafer board.

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.

Wrinkle

A slight ridge caused by folding, rumpling or creasing. In roofing usually refers to the common ‘wrinkling” pattern that forms over the joints on insulation in insulated roof systems.