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Roofing Glossary

Residential Ventilation

Residential Roofing Glossary

3-tab shingle: An asphalt shingle comprised of a single layer with the exposed area separated by cut-outs into three tabs that are approximately 12 to 13 inches.

Algae Discoloration: A type of roof discoloration caused by algae. Commonly described incorrectly as fungus growth.

APP: Atactic polypropylene. A plastic polymer used in the modification of asphalt.

Architectural shingle: An asphalt shingle made up of multiple layers. The tabs on these shingles are cut to different sizes and shapes to give the roof a more three-dimensional appearance. Also called dimensional or laminated shingles.

ARMA: The Asphalt Roofing Manufacturers Association, a trade association for North American manufacturers of asphalt roofing.

Asphalt Primer: A thin laiquid bitumen applied to a surface to improve the adhesion of self-adhering membranes and to absorb dust.

Asphalt Roofing 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) or ASTM D 2822 (Asbestos Containing) or CGSB 37-GP-5MA.

Asphalt Shingle: A shingle manufactured by coating a reinforcing material (felt or fibrous glass mat) with asphalt and having mineral granules on the side exposed to the weather.

Asphalt: A bituminous waterproofing agent applied to roofing materials during manufacture.

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

Attic vent: An opening that allows air, heat, and water vapor to escape from the attic. This helps prevent damage to roofing materials caused by overheating.

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

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

Balanced System: Equal amounts of intake net free area ventilation low at the roof’s edge or in the soffit and exhaust net free area ventilation at or near the ridge. Outside air enters the attic space through soffit or eave vents, rises through the attic space as it warms, and exits through vents that are positioned at or near the top. For this method to be most effective, approximately equal amounts of ventilation should be placed at the soffits or eave level, and at or near the top of the attic space.

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

Base-ply sheet: A product intended to be the base or middle ply in a residential self-adhering roll roofing system.

Bernoulli Effect: A type of air movement whereby the movement of wind passing over the ridge creates a low-pressure area and has the effect of pulling air out of the attic through exhaust vents located on the ridge or off ridge near the top of the roof.

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

Box vent: See static vent

Brands: Airborne burning embers released from a fire.

Bridging: A method of re-roofing with larger-sized shingles.

Built-up Roof: A low-slope (or flat-seeming) roof covered with alternating layers of roofing felt and hot-mapped asphalt and topped off with a layer of gravel.

Bundle: A package of shingles.

Butt Edge: The lower edge of the shingle tabs.

CAN: This designation in front of a CSA, CGSB or ULC represents that it is a Canadian national standard.

Cap Sheet: A mineral surfaced material that is used by itself or as the top layer of multi-layer rolled roof covering system.

Caulk: Using mastic or asphalt cement to fill a joint to prevent leaks.

CFM: Cubic feet of air moved per minute. All motorized vents have a CFM rating that defines the vent’s capacity to move air. The higher the CFM number, the greater the vent’s capacity.

Chalk Line: A line made on the roof by snapping a taut string or cord dusted with chalk. Used for cutting slots for ridge vents

Chimney Effect: Relies on convection and occurs when cool air enters a home on the first floor or basement, absorbs heat in the room, rises, and exits through upstairs windows. This creates a partial vacuum, which pulls more air in through lower-level windows.

Class “A” Fire Resistance: The highest fire test classification for roofing as per ASTM E108 or UL790. Indicates roofing is able to withstand severe exposure to fire originating from sources outside the building.

Class “B” Fire Resistance: Fire test classification that indicates roofing material is able to withstand moderate exposure to fire originating from sources outside the building.

Class “C” Fire Resistance: Fire test classification that indicates roofing material is able to withstand light exposure to fire originating from sources outside the building.

Class 4 Impact Resistance: The highest impact resistance classification as per the UL 2218 Impact test indicating that shingles are more resistant to impacts resulting from hail storms.

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 50 mm (2″) 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.

Cold Roof: The condition in which the roof temperature is equalized from top to bottom. An equalized roof temperature can help eliminate the conditions that can lead to the formation of ice dams.

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

Conduction: Flow of heat directly through a solid material such as shingles, roof deck and is responsible for most heat loss or gain in a residence.

Collar: 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, overlapped 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.

Continuous Soffit Vents: Continuous soffit vents are longer, and often wrap around the entire eaves of a home. Much like a ridge vent (which runs along the entire peak of a roof), continuous soffits provide lots of bang for your buck because there is more surface area. The greater the surface area, the more air can pass through. Continuous soffits are generally made of vinyl with intake holes drilled in. Because they’re vinyl, they come on a wide array of textures and colors to match the look and feel of almost any home

Convection: Transfer of heat typically associated with the rise of hot air within a building stricture such as an attic.

Cool roof shingle: Shingles that are specially designed to remain at lower temperatures than traditional, non-reflective shingles when exposed to the sun’s rays, which may reduce attic temperature and help save on cooling costs.

Cornice: The portion of the roof projecting out from the side walls of the house.

Counterflashing: The flashing which is imbedded at its top in a wall or other vertical structure and is lapped down over shingle flashing.

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

Coverage: A mount of weather protection provided by the roofing material. Depends on the 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 the accumulation of snow and ice, and to deflect water around the chimney.

CSA: Canadian Standards Association. A voluntary organization concerned with development of consensus standards, testing procedures and specifications.

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

Deck, Decking or Sheathing: The structural “skin” of a roof over which roofing is applied. Most new homes have decking made of plywood. There are four main types of decking commonly used on residential roofing projects:

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

Decking: The structural material over which roofing is applied. Usually plywood, boards, or planks.

Designer shingle: Asphalt roofing shingles with highest-end multidimensional designs made to appear similar to slate or wood shake shingles. Often called a “premium” or “luxury” shingles.

Dimensional shingle: Another name for an architectural shingle.

Dormer: A framed window unit projecting through the sloping plane of a roof

Double Coverage: Application of asphalt roofing such that the lapped portion is at least 2″ (50 mm) wider than the exposed portion, resulting in two layers of roofing material attached to 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.

Drip: The strip of metal extending out beyond the eaves or rakes to prevent rainwater from rolling around the shingles back onto the wooden portion of the house.

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

Eaves: The lower edge of a roof (usually overhanging beyond the edge of the house).

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.

Exhaust Vent: Vents located at the top of the attic at the ridge or near the ridge that remove heat from the attic in the summer and moisture from the attic in the winter.

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.

Exposure I Grade Plywood: Type of plywood approved by the American Plywood Association for exterior use.

Exposure: That portion of the roofing exposed to the weather after installation.

Eyebrow Vents: An off-ridge vent is only similar to a ridge vent because they both sit close to the crest of your roof. In fact, “off ridge vents” are much more similar to box vents than they are to ridge vents! is only form of exhaust on your roof, then you’ll run into trouble on hot summer days without any wind. Off ridge vents are not as effective as full ridge vents because they are much smaller and do not sit as high on the roof. Their size prohibits them from expelling a large amount of hot air and their location restricts their ability to vent the absolute hottest air, like a ridge vent. Off ridge vents are advantageous when the actual ridge line of the roof is small. This can happen with complex roofs and homes that do not have one long, continues ridge line for a traditional ridge vent to run across. Adding an off-ridge vent or two to these types of roofs can provide an added punch of ventilation to areas that don’t have enough.

Fascia or Fascia Board: Horizontal trim at the eaves that covers the rafter ends.

Fascia: Trim board behind the gutter and eaves.

Felt: The “tar paper” used by roofer, usually made of a combination of asphalt and either paper or rags.

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. There are 4 main types of flashing used in residential roofing systems:

Flashing cement: See Asphalt Roof Cement.

Flashing: Sheet metal or other material used at junctions of different planes on a roof to prevent leakage.

FM: Factory Mutual Research Corporation is a scientific research and testing facility that works with commercial and industrial clients to ensure that their products and services meet standards and approvals. For roofing systems and products, Factory Mutual provides testing and certification services for items such as fire resistance, wind resistance, and impact resistance.

Frieze Board: A Board at the top of the house’s siding, forming a corner with the soffit.

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.

Gable: The triangular upper part of a wall closing the end of a ridged roof

Gable Vents: Gable vents are an older, somewhat outdated, style of intake that also partially functions as an exhaust system. Unlike with vertical ventilation, gable vents utilize horizontal or cross-ventilation to help keep air moving through the attic space. The basic premise is that air flows in on one side of the attic, then out through the other. A gable vent is mostly used with a gable style roof because a vent can be placed on each side of the home. These vents are not as effective on more complex roof styles because the cross breeze can be impeded by rafter beams, peaks, valleys, dormers and other parts of the roof.

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

Gambrel: 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. A gambrel roof usually contains a gable at each end, just like a standard gable roof.

Granules: Ceramic-coated colored crushed rock that is applied to the exposed surface of asphalt roofing products. Granules protect the asphalt coating from the sun’s rays, add color to the product and enhance fire resistance.

Gutter: The trough that channels water from the eaves to the downspout. Also known as an eavestrough.

Hardwired Powered Attic Vents: Are electric-propelled fans that help pull stale air out of an attic space. They work much like a box fan placed in a window on a hot summer day. They can effectively pull the hot air out, but come with…higher electricity costs. Their power can often be either detrimental to a ventilation strategy, or not powerful enough to make a difference at all… This suggests that the powered vents could actually be pulling cooler air up through the main floors of the home and out of the attic, thereby increasing energy costs and forcing the air conditioning unit work harder. Vent fans have the potential to reduce measured peak summer attic air temperatures by over 20 degrees. However, the impact over the cooling season is fairly modest with well insulated attics.” Weaker power vents have a tendency to circulate air rather than expel air. Higher operational costs are a substantial reason why traditional hard-wired systems have transitioned to solar power over the last few years.

Headlap: 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.

Hexagonal Shingles: Shingles that have the appearance of a hexagon after installation.

High nailing: When shingles are fastened above the manufacturer’s suggested nailing location.

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.

Hip: The external angle at the junction of two sides of a roof whose supporting walls adjoin.

Ice Dam: Ice dams occur when snow melts near the ridgelines 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.

Ice Dam Protection: One or more courses of self-adhering underlayment installed at the eaves of a building to prevent damage from water back-up due to an ice dam. Also known as “Eave Flashing”.

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

Individual soffit vents: These are more like box vents. They’re smaller, generally rectangular in shape, and are placed 5 to 6 feet apart along the eaves. Because individual soffits are spaced out, they are not as effective as continuous systems because they provide less surface area for air intake.

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.

Joist: In a flat roof, a horizontal structural member over which sheathing is nailed.

Laminated Shingles: Strip shingles containing more than one layer of tabs to create extra thickness.

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

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

Lead flashing: When working with tile roofs, lead flashing is used. In the case of a plumbing vent flashing, the lead flashing is actually molded to the shape of the tile’s surface. Then the top of the lead flashing is covered by the next tile to prevent water from seeping under the flashing.

Louver Vent: See static vents

Low Slope Application: Method of installing asphalt shingles on roof slopes 2:12 (9.5°) – 4:12 (18.4°).

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: See Asphalt Roof Cement.

Mid-ply Sheet: See Base-ply sheet.

Mineral Stabilizers: Finely ground limestone, slate, trap rock or other inert materials added to asphalt in shingles for durability and increased resistance to fire and weathering.

Mineral-Surfaced Roofing: Asphalt shingles and rolled roofing that are covered with granules.

Minimum Vents Area: The minimum net free ventilating area shall be 1/150 of the area of the vented space. Exception: The minimum net free ventilation area shall be 1/300 of the vented space, provided both of the following conditions are met: In Climate Zones 6, 7, and 8, a Class I or II vapor retarder is installed on the warm-in-winter side of the ceiling.

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.

Net Free Area (NFA): The total unobstructed area through which air can enter or exhaust a non-powered vent; generally measured in square inches. All nonpowered vents have a Net Free Area rating.

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

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

Non-Woven Vents: Non-Woven Polyester Fiber ingle-layer ridge vent can be used under ridge caps, ridge shingles and as a fascia vent to keep attics cooler in summer and dryer in winter. Ideal for all roof applications. Helps reduce utility costs, and is non-wicking to help keep out insects, dust and moisture.

Off-Ridge Vent: Exhaust vents not installed at the ridge but typically within two feet of the ridge equally spaced along the slope.

Offset: The distance between the edge of one shingle course and the edge of the next successive shingle course.

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.

OSB (Oriented Strand Board): OSB is cheaper than plywood, but not as strong as plywood, and does not hold nails as well as plywood. One side has a slip resistant coating and should be placed facing up.

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

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

Penetration: Any construction passing through the roofing system, such as vent piping, conduits, and HVAC equipment supports.

Pitch: Also known as “slope”, pitch is the measure of how “steep” a roof is. For example, if a roof is “4 in 12″, the roof rises 4 inches for every horizontal run of 12 inches. The pitch of the roof is a big factor in determining the kinds of materials that can be used and the longevity of the roof. Usually, a steeper roof (higher pitch) will last longer due to its better drainage capabilities.

Plumbing vent flashing: Plumbing vent flashing prevents rainwater from running into holes cut for pipes in the roof. This flashing is sold according to the size of the vent pipe and the roof angle. Roofing material is installed over the flashing.

Ply: A layer of roofing (i.e., one-ply, two-ply).

Plywood: Plywood is strong, durable, and light. It comes in many grades with ratings from A to D. Use only exterior grade plywood for decking. The thickness of plywood depends on the spacing of the rafters.

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.

Primer: An asphalt-based primer used to prepare surfaces for bonding with self-adhering asphalt sheets.

R-Value: Thermal resistance, a measure of a material’s or a construction’s ability to retard heat flow. R-Values in a series of materials can be added to determine a construction’s total thermal resistance. The typical application is the use of insulation in attics

Racking: Roofing application method in which shingle courses are applied vertically up the roof rather than across and up. Typically, this is not a recommended procedure.

Rafter: A structural member (usually slanted) to which sheathing is nailed.

Rake: The slanting edge of a gabled roof extending beyond the end wall of the house.

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

Recovering: The process of adding an additional layer of roofing over an existing layer. A maximum of two layers of any roofing type are permitted on a roof at any time.

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

Reroofing: The process of removing existing roof coverings and replacing with a new roofing system.

Ridge cap shingles: Material specifically made to cover the peak ridge or hips of the roof.

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

Ridge Vent: Vent placed along the ridge of the roof. It allows ventilation of the roof by raising the LEVEL of the ridge slightly leaving room for air flow. A filtration fabric placed in the side vents allows air to move through while preventing insects from entering. A ridge vent sits at the peak of your roof and runs across the entire span of your roof line. Because ridge vents are located at the roof’s highest point, they are in prime position to let the hottest air escape the attic space. They run across the entire roof line & have the surface area necessary for expelling large amounts of hot air. Because ridge vents are located at the roof’s highest point, they are in prime position to let the hottest air escape the attic space.

Ridge: The horizontal line at the top edge of two sloping roof planes.

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

Roll Roofing: Asphalt roofing products manufactured in roll form.

Roof deck protection: Also known as underlayment, these products are often synthetic or fiberglass-reinforced felts. They provide a water-shedding secondary layer of protection under the final roof covering.

Roof ridge vent: An air slot cut into the roof deck at the highest point on the roof. The vent construction protects the inside from the weather while allowing air to flow freely through the attic.

Roof Turbines: Also known as whirlybirds and rely on wind force to draw air from the attic.

Roofing felt: A material laid down on top of the roof decking to protect the structure underneath. Typically made of asphalt-saturated paper or synthetic materials. Similar to underlayment.

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

Roofing underlayment: Asphaltic saturated organic or synthetic-based rolled materials designed to be installed under the main roofing materials to help shed water and resist weather infiltration. Sometimes referred to as felt.

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.

SBS: Styrene-Butadiene-Styrene, which is a synthetic polymer that is mixed with asphalt in some products to increase the flexibility and other attributes of the products.

Self-Adhered Eave and Flashing Membrane: A self-adhering bituminous waterproofing shingle underlayment designed to protect against water infiltration due to ice dams and wind-driven rain.

Self-Sealing Shingles: Shingles containing factory-applied strips or spots of 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: That portion of roll roofing overlapped by the succeeding course to obtain single or double coverage at the lap.

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

Sheathing: The rigid material (often 1-inch by 6-inch or one inch by twelve-inch boards or sheets of plywood) which is nailed to the rafters, and to which shingles or other outside roofing materials are secured.

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

Shiner: When shingles are fastened below the manufacturer’s suggested nailing location. This can cause the nail to rust out, leading to water intrusion.

Shingle Flashing: Flashing that is laid in strips under each shingle and bent up the edge of a chimney or wall.

Shingle: A small piece of roofing material designed to be installed in overlapping rows or courses.

Short circuits: Often, static exhaust vents are installed on a roof that also has a ridge vent. This follows the belief, “the more the merrier” or that you can never have too much ventilation. However, this construction should be avoided, because the static exhaust vents create a “short circuit” of the intended air flow.

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

Slope: The steepness of the roof expressed as a ratio. For example, a 4:12 slope means there are 4″ of vertical rise for every 12″ of horizontal length.

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

Soffit: The boards that enclose the underside of that portion of the roof which extends out beyond the sidewalls of the house.

Soffit Vents: Exhaust ventilation without any intake is like having a bike without pedals. The air may be able to move a little, but it won’t get very far! Soffit ventilation is by far the most popular form of roof intake venting. It forms one half of the most popular combination of intake and exhaust; soffit vents (for intake) with a ridge vent (for exhaust). Soffit vents are a favorite amongst home builders and roofers because they are unquestionably the most effective intake vent for the cost. If a home’s style allows for it, most new construction builders include soffit vents in their home’s blueprint. Soffits are intake vents that installed directly on your eaves, which are located directly underneath your roof line. Some folks refer to this area as the “roof overhang”. There are different types of soffits, but almost all of the most common designs have small holes that allow cool air to flow into your attic space, where it helps push hot air out of your home through the exhaust vent. And do not fret, the soffit’s holes are very small, so unwelcome critters cannot make their way into your house.

Soil boot: A vent pipe that penetrates the roof.

Soil Stack: A vent pipe that penetrates the roof.

Solar panels: Racked solar panels (aka modules), which are separate from and on top of your roof, with the panels attached by dozens of roof penetrations

Solar roofing: A roofing system in which the solar is integrated into your home’s roof materials.

Solar Vents: Solar-powered attic ventilation removes almost 100% of the electricity costs associated with older hard-wired vents but does not eliminate the negatives that come with powered attic vents in general. Simply removing electricity costs does not change the way the unit operates. The fans are often either too powerful, or not powerful enough. There’s unfortunately no way to guarantee you get it just right. And when added on top of a proper vertical ventilation strategy (like a ridge vent exhaust and soffit vent intake), powered vents can actually have damaging effects that wouldn’t have otherwise existed.

Square: One hundred square feet of roof, or the amount of roofing material needed to cover 100 square feet when properly applied.

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

Stack Pressure: A positive pressure area is created at the top of a building and negative pressure area at the bottom. This process can take place without mechanical assistance, simply by introducing openings at the bottom and the top of buildings. It is known as the stack effect or stack ventilation.

Standard Slope Application: Method of installing asphalt shingles on roof slopes 4” to 21” per foot.

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

Static Vent: Static ventilation uses non-powered ventilation products to cool the home. These products work with the natural flow of air and temperature. Here’s how static ventilation works: As air heats up, it rises and becomes less dense. The wind movement around and over a home creates areas of low and high pressure.

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

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

Step sheathing: Step sheathing is used alone or in combinations with solid sheathing for installation of tiles or shakes. Step sheathing allows air circulations under the tiles by using 1-by-6 or 2-by-6 boards that are evenly spaced so that air can move under the tiles or shakes.

Strip Shingles: Asphalt shingles made from a single layer that are approximately three times as long as they are wide.

Synthetic Underlayment: An underlayment product that is typically manufactured using polypropylene and is used as an alternative to felt underlayment.

Tab: The exposed portion of strip shingles defined by cut-outs.

Tear Off: To remove an existing roofing system down to the structural deck.

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.

Tongue and groove 2-by-6: If a roof will be seen from the inside (no ceiling installed), tongue and groove is used. It is a wood decking that provides great insulation without additional rigid roof insulation in moderate climates. Also, the boards can be painted or stained on the inside to match the interior.

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

Turbine Vents: Roof turbines need winds of at least 5 to 6 miles per hour to activate and spin the interior blades, which means that they won’t be effective on days with a slight breeze or no breeze at all. If this is only form of exhaust on your roof, then you’ll run into trouble on hot summer days without any wind

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

Underlayment: The material (usually roofing felt) laid on top of sheathing before shingles are applied. Valley The less-than 180-degree angle where two sloping roof sections come together.

Valley flashing: This flashing is used in open valleys of the roof. Most often leaks are found in the valley flashings due to flashing that is nailed too tightly to the decking or shingles that are not trimmed far enough off the flashing.

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

Vapor retarder: A material used to impede the passage or movement of water vapor. Usually included as a layer during roofing installation. Applied to insulation or other surfaces, it retards vapor travel to regions of low temperature where it may condense. A material is considered a vapor retarder if it has a perm rating of 1 or less.

Vent Sleeve: See Collar.

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.

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.


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