Asphalt (Composition) Shingles: These shingles are made of a base (organic or fiberglass) that is saturated with asphalt and coated with minerals on one side to resist weathering. The fiberglass shingles are more flexible and stronger than organic shingles. Shingles come in a wide variety of colors. The life expectancy of composition shingles depends on the rating (e.g., quality) and ranges from 20 years to lifetime. Most manufacturers will provide a material warranty, but only if it has been installed by a certified roofer.

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

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

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

Cedar Shake: Cedar shakes combine a traditional look with reliable, modern performance. Cedar shakes are a great choice for historic homes or homes in new developments with high appearance standards. Also, cedar shakes are an environmentally friendly option for consumers. The life expectancy of cedar shakes is up to 30 years, if quality materials are used. If the contractor uses commodity materials (low quality) or if the workmanship is poor, the life expectancy can drop to only 5 to 8 years. Another concern potentially associated with cedar shakes is that many communities will require you to install pressure-treated fire retardant shakes, which increases the cost of the materials.

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.

Course: A row of shingles running the length of the roof.

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.

Cupola: A structure rising above the main roof. It is usually ornamental, but may be used for ventilation.

Deck: Also known as decking. The surface installed over the supporting framing members of a building. It is 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:

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.

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.

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.

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.

Dimensional/Architectural Shingle: Dimensional shingles are very similar to composition shingles, but are thicker, and can be used to create a more custom appearance. Depending on the rating, dimensional shingles also have a much better lifespan.

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

Downspout: A pipe for draining water from roof gutters.

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.

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.

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

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

Flashing: Flashing is one of the most important elements of the roof because it seals the seams and joints of the roof. Pieces of metal or roll roofing are 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. There are several types of flashing used in residential roofing systems:

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.

Step Flashing: When a chimney or dormer wall intercepts the slope of the roof, step flashing is used. Step flashing is usually a metal piece that is bent in the middle, so that one end lays on the roof, and the other against the vertical wall of the dormer or chimney. Step Flashing is generally in 4 by 4 by 8 inch pieces.

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 to tightly to the decking or shingles that are not trimmed far enough off the flashing.

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

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.

Granules: Ceramic-coated colored crushed rock that is applied to the exposed surface of asphalt roofing products
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Gutter: The trough that channels water from the eaves to the downspouts.

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.

Laminated Shingles: Shingles containing more than one layer of tabs creating extra thickness. (AKA dimensional or architectural)

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

Pitch: Also known as "slope", pitch is the measure of how "steep" a roof is. For example, if a roof is a 4/12 pitch, 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.

Rafter: The supporting framing member immediately beneath the deck, sloping from the ridge to the eave.

Rake: The inclined edge of a sloped roof over a wall from the eave to the ridge. These two slopes meet at the peak or ridge. Trim that goes on these slopes is referred to as “gable or rake trim”. We typically use the term “gable trim”.

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. Trim that covers this area is called “ridge cap”.

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

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

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

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.

Slope: The degree of roof incline expressed as the ratio of the rise, in inches, to the run, in feet…also referred to as “pitch”.

Slope Applications: Divided into three categories, this is the application of roofing materials to a roof based upon its slope or pitch. The three categories are known as “steep slope application, “normal slope application” or “low slope application”.

Steep Slope Application: Method of installing roofing material on roof slopes greater than 21 inches per foot.

Normal Slope Application: Method of installing roofing materials on roof slopes between 4 inches and 21 inches per foot.

Low Slope Application: Method of installing roofing materials on roof slopes between two and four inches per foot.

Soffit: The finished underside of the eaves.

Square: A unit of roof measure covering 100 square feet.

Starter Course: The first course of shingles installed on your roof; it will be under the first exposed row.

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

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

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.

Weathering: Changes in color, texture or efficiency brought about by exposure to outside elements.