Common Roofing Terms To Aid Homeowners

Roofing Glossary

Common Roofing Term Definitions to Aid Homeowners

Doing a roof replacement or even repairing a roof is not something that happens everyday for most homeowners. The odds are most homeowners are general not thinking about it.

At Certified Precision Roofing we pride ourselves on being among the most knowledgable and respected home improvement contractors in Georgia.

Below we have composed a list of common Roofing terms and definitions along with some drawings to help you get a little more familiar with your roof.


Roofing TermsRoofing Terms


Algae discoloration: A type of roof discoloration caused by algae, also know as fungus growth.

Asphalt: A bituminous waterproofing substance applied to materials during manufacturing process.

Asphalt roofing cement: An asphalt plastic based cement used to bond roofing materials. Also known as flashing cement or mastic.

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

Base or Foundation flashing: That portion of the flashing joined to or attached to the deck. This helps with directing the flow of water onto the roof covering.

Blisters: Small circles (bubbles) that may appear on the upper surface of asphalt roofing after installation.

Built-up roof or Stacked Roof: A flat or low-sloped roof consisting of several layers of asphalt and plywood sheets.

Butt edge: The lower edge of the shingle tabs.

Caulk:  A matter used to fill a joint with asphalt cement to prevent leaks.

Chalk line: An inner line in a device which by snapping the string or cord dusted with colored chalk creates a mark . Used for alignment purposes.

Class "A" Rating: The highest fire-resistance rating for roofing. This indicates the roof is able to withstand severe exposure to fire originating from outside the building.

Class "B" Rating: A step down from A rating, B rating fire-resistance rating indicates roofing materials should be able to withstand moderate exposure to fire originating from sources outside the building.

Class "C" Rating: Fire-resistance rating to light fire exposure from a source outside of the house.

Closed cut valley: A method of valley protection in which shingles from one side of the valley (where to sides of the roof meet) extend across the valley while shingles from the other side are trimmed two inches from the valley centerline. The main purpose of this is to avoid exposing the valley.

Coating: A layer of viscous asphalt applied to the surface. The base material is usually underneath into which granules or other surfacing is applied.

Pipe Collar: Pre-formed flange placed on a roof vent pipe to seal around the pipe opening. Also knows as a vent sleeve.

Concealed nail method:  Method of roll roofing in which the nails are driven into the underlying course of roofing and covered by a roofing cemented substance, overlapping course. This avoids having the nails totally exposed to the weather.

Condensation Process: The process that water goes through from vapor to liquid when warm, moisture-laden air comes in contact with a cold surface.

Counter flashing: That vertical surface that needs to be covered in order to prevent water from migrating behind the base flashing.

Course: A row of shingles or roll roofing, which runs horizontally the length of the roof.

Roof Deck: The upper surface installed over the supporting roof framing members to which the roofing will be applied.

Dormer: An roof window opening or framed window unit designed through the sloping plane of a roof.

Downspout: A pipe that helps with draining the water from roof gutters. Also known as a leader.

Drip edge: A matter that is non-corrosive, non-staining used along the eaves and rakes to direct the water run-off to drip clear of underlying construction avoiding damage to the roof over the years.

Eaves: The horizontal part of the lower edge of a sloped roof.

Eaves flashing: Additional material applied to the eaves in order to help with water back-up to avoid damage over time.

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

Felt: material that is combined with asphalt and used predominately for the  underlayment or sheathing paper.

Fiber glass mat:  A combination of asphalt base material manufactured with glass fibers.

Flashing: Usually a 26-gauge pieces of metal applied against the intersection or projections on the roof in order to prevent water into a building. It is also applied to vent pipes, chimneys, adjoining walls, dormers and valleys.

Flashing Cement: Substance composed with asphalt plastic roofing cement.

Gable: The upper portion or also know as the top corner of a sidewall that comes to a triangular point at the ridge of a sloping house roof.

Gable roof: A style of roof containing sloping planes of the same or very similar pitch on each side of the ridge. Usually contains a gable at each end.

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

Gutter:  Attached to the sides of lower part of the roof. The trough (container) that channels water from the eaves to the downspouts.

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.

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

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

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

Ice dam: Certain condition formed at the lower part of the roof edge by the thawing and re-freezing of melted snow on the overhang. This can force water upwards and under shingles, causing possible leaks.

Laminated shingles: Shingles with more than one layer of tabs to create additional thickness. Also knowns as three-dimensional shingles.

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

Nesting Roofing Method: A process of re-roofing with new asphalt shingles over old shingles. This is where the top edge of the new shingle is placed against the bottom edge of the existing shingle tab.

Normal slope application: Method of applying asphalt shingles on roof slopes between four inches and 21 inches per foot.

Open valley: Application of valley construction ( where to side of the roof meet) in which shingles on both sides of the valley are trimmed. Asphalt shingles do not extend across the valley. Valley flashing is exposed.

Organic Roofing felt: An asphalt roofing base material manufactured from cellulose fibers.

Overhang Structure: Portion of the roof structure that extends beyond the exterior walls of a building.

Roof Pitch: The degree of roof incline is measured as the ratio of the rise, expressed in feet, to the span, also in feet.

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

Quick-setting asphalt cement: An asphalt-based cement applied to adhere tabs of strip shingles to the course underneath. Also known to be used under the concealed nail method.

Rake: Related to roofing -  inclined edge of a sloped roof over a wall from the eave to the ridge ( Two Sloping Roofs).

Roof Ridge: The uppermost, horizontal angle formed by the intersection of two sloping roof sides.

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

Roofing tape: A material applied to repair a patch on the roof. Roofing tape is asphalt-saturated tape used with asphalt cements. 

Saturated roof felt: An asphalt-based felt used as an underlayment between the deck and the top roofing materials.

Self-sealing shingles: Roof shingles containing factory-applied strips.

Single Roof Coverage: Asphalt shingles applied to the roof, which provides one layer of roofing material on top of the deck.

Slope of the roof: The measure of the roof incline expressed as the ratio usually in inches and feet.

Soil stack: A vent pipe that that goes through the roof.

Roof Span: The horizontal distance from eaves to eaves.

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

Starter Eaves Strip: A method used to apply asphalt roofing at the eaves in order to provide protection by filling in the spots under the cutouts and joints of the first course of shingles.

Steep Slope Roof: Is a method of installing asphalt shingles on roof slopes that are greater than 21 inches per foot.

Strip shingles Roofing: Asphalt shingles that are approximately much longer, usually three times as long as they are wide.

Tab Shingles: The exposed portion of strip shingles defined by cutouts.

Telegraphing: Asphalt shingle distortion that may come about when a new roof is installed over an uneven surface.

Three-tab shingle: By far the most popular type of asphalt shingle usually measures 12" x 36" in size with three tabs.

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

Underlayment or Tar PaperA layer of asphalt matter saturated, also known as tar paper. This is usually laid down on a bare deck before shingles are installed to provide additional protection for the deck.

Roof Valley: An angle formed by the intersection of two sloping roof planes to provide water runoff.

Woven Valley: Roofing application of valley construction. A method where shingles from both sides of the valley go across the valley. The method then goes further and the shingles are woven together by overlapping alternate courses as they are applied. The purpose of the woven valley is not to have the flashing exposed.