Roofing, Guttering & Soffit/Fascia Terms

Algae — A type of fungus that can leave dark stains on a roof.

Angled fasteners — An installation-related problem that occurs when the shaft of roofing nails or staples are driven into decks at angles that are not perpendicular to the roof's deck.

Asphalt — A bituminous waterproofing agent used in various types of roofing materials.

Blistering — Bubbles in roofing materials that are usually caused by a poorly insulated roof and are usually moisture-related.

Blow-offs — When shingles are torn loose from their position on the roof by high winds. Shingles that are nearing the end of their normal life cycle are prone to blow-offs, as are shingles that have been improperly installed (i.e., angled, under-driven or over-driven fasteners or high nails and/or over-exposed shingles).

Buckling — A wrinkle or ripple in the shingles or underlayment.

Built-up roof — A flat or extremely low-sloped roof consisting of multiple layers of asphalt and single-ply sheets.

Caulk — A flexible product that is used to fill joints and cracks or to help seal intersecting seams and joints between various features of a roof.

Closed-cut valley — A valley installation method where one roof plane's shingles completely covers the adjacent section's shingles. The top/overlapping layer is then cut in a straight line roughly parallel to the line formed by the valley itself.

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

Counter flashing — Metal that is attached to a vertical service to prevent water from migrating behind the base flashing and/or shingles.

Course — A row of shingles or roll roofing running the entire length of a section of the roof.

Cricket — A peaked water diverter installed behind chimneys (connecting the back of the chimney to the sloped section of the roof through which it is penetrating) and other large roof penetrations/projections.

Cupping — When shingles are improperly installed over an existing roof or are over-exposed a curl or cup will often form.

Curling — An imperfection in the shingle where the outside corners curl upwards, eventually pulling the shingle free from the seal strip and making the shingle much more vulnerable to blow-offs from high winds.

Decking — The surface the roof is attached to. Typically, the roof deck is made up of either plywood, oriented strand board (i.e., OSB, made from wood chips and lamination glues), 3/4" spaced sheathing/planks or 3/4" tongue and groove boards.

Dormer — A structure projecting out perpendicular from another sloped section of the roof. Most dormers are built for the purpose of allowing for the installation of windows in rooms that have sloped ceilings.

Downspout — A pipe for draining water from a structure's guttering system.

Drip edge — Also called "edge metal." A piece of L-shaped metal (normally aluminum) that is installed to along the bottom ("eaves") and/or outer (i.e., "rake") edges of the roof to force water to drip clear of the roof deck and prevent water from backing up underneath shingles. Along the eaves of the roof, the water normally flows over the outside edge/"face" of the edge metal and into some form of guttering.

Eave — The bottom edge of the roof, from the fascia to the structure's outside wall underneath and up the slope of the roof approximately three feet (on most structures). Thus, collectively, the fascia, soffit and bottom three feet of the roof deck make up the "eave."

Exposure — The area on any roofing material that is left exposed to the elements.

Fascia — The board or metal (normally perpendicular to the ground) that is attached to the end of the rafters. It is the piece that the guttering is normally attached to.

Fasteners — Nails, staples or screws used for the purpose of securing waterproofing materials to the roof deck.

Felt paper — Paper made out of an asphalt-based material that is installed between roofing and the decking. Typically either 15# or 30# felt is used on "steep slope" roofs. The material is sometimes applied in two layers on roofs with lower slopes.

Fiberglass mat — Fibers condensed into strong, resilient mats for use in roofing materials.

Flashing — Metal that is installed wherever two or more surfaces meet to keep out water. This can also refer to any device that is used to provide waterproofing around various types of penetrations in the roof (i.e., chimney, bathroom sanitary vent pipe, electrical mast, flue pipe, etc.).

Gable roof — A traditional roof style where two sloped planes/sections meet at a ridge line of equal size. It is essentially an inverted "V."

Granules — Crushed rock that is coated with a ceramic coating and fired. They are then used as the top surface for asphalt-based shingles and roll roofing.

High nailing — When staples or nails are installed well above the manufacturer's designated nail location/zone. Installing fasteners as little as an inch above this location/zone can dramatically reduce the fastener's holding power.

Hip — The inclined external angle formed by the intersection of two adjacent sloping roof planes.

Hip legs — A straight line that runs from the outside corner of the eave edge of the roof up to the nearest ridge.

Hip roof — A roof with four roof planes coming together at a shared peak or separate peaks connected via a continuous ridge and possessing four separate hip "legs."

Ice and water shield — A high-quality underlayment that provides extra protection for the roof deck in vulnerable areas of the roof. Typically installed along eaves that have a history of ice dams. Can also be used around roof penetrations, in valleys and along the rakes of the roof.

Ice Dam — A condition that forms at the eave edge/overhang of the roof when snow thaws and re-freezes. Water can then be forced up and under shingles, causing leakage and severe water damage. While it is sometimes caused by improper roof ventilation, it can also develop because of unique weather conditions and occur only on the rarest of occasions.

Laminated shingles — Shingles made by laminating two separate pieces together.

Low slope — Roof pitches less than 4/12 are considered low sloped roofs. Special installation practices must be used on roof pitches between 2/12 and 4/12 if shingles are being installed.

Mansard roof — A roof design with a nearly vertical roof plane that ties into a roof plane of less slope at its peak. Such roofs contain no gables.

Mats — The base material of shingles and various rolled products.

Nail pop — When a nail is not fully driven down onto the shingle or simply works its way loose over a period of time. Bad nail pops can eventually push their way through the shingle that is sitting on top of them and allow water to enter the structure.

Normal slope — When the roof pitch is between 4/12 and 21/12. Standard shingle installation practices are used.

NRCA — The National Roofing Contractors Association.

Open valley — A valley installation method where adjacent sections of shingles meet in a "V" but do not overlap each other (and are cut parallel to each other, leaving a gap of several inches). Some "open" valleys utilize a granular-based product underneath the two parallel cuts in the adjacent sections of shingles, while others use metal (normally copper).

Organic shingles — Shingles made from organic (i.e., recycled paper and cardboard) mats. (NOTE: Many people call these shingles "asphalt shingles," which tends to cause some confusion since asphalt is the primary component in both organic and fiberglass shingles.)

OSB — Oriented strand board. A type of decking material made from wood chips and lamination glues.

Over-driven fasteners — A problem that occurs when roofing fasteners (i.e., nails or staples) are driven with too much force through the shingles. Some fasteners completely penetrate the shingles, while others cause cracks in the shingles. Either way, the shingles will be extremely vulnerable to high winds and wind driven rain and snow.

Over-exposed — When shingles are installed above the point that is recommended by the shingle manufacturer.

Penetrations — Anything that penetrates the roof from the underside such as a chimney, bathroom sanitary vent pipe, exhaust vent, electrical mast or flue pipe.

Power vents — Electrically-powered fans used to remove hot and/or moist air from attics and other structures.

Racking — A method of installing shingles in a vertical manner up the roof.

Rafter — The supporting framing members immediately beneath the deck, running from the top of the wall (i.e., the "top plate") to the ridge or peak of the roof. The roof deck is fastened directly to the rafters.

Rake — The vertical outside edge of a gable-styled roof plane.

Ridge — Typically known as the roof peak, where two sloped sections meet at the top of the roof.

Ridge vent — A type of ventilation system that allows attic air to exit the roof at the ridge or peak.

Rise — The vertical distance from the eave line to the ridge/peak of the roof.

Roll roofing — Asphalt roofing products manufactured and delivered in roll form (normally three feet wide).

Roofing — Material (i.e., shingles, wood shakes, clay tiles, metal, rubber, rolled roofing, etc.) used to waterproof the roof deck of a structure.

Roof plane — A roofing area defined by having three (in the case of triangles) or four (in the case of rectangles and trapezoids) separate edges. One side of a gable, hip or mansard roof.

Run — The horizontal distance from the eave to a point directly underneath the ridge. Also, half the distance of the overall distance from one eave to a corresponding eave.

Shed roof — Roof design with only a single roof plane. The roof does not have any ridges, hips, gables or valleys.

Slope — How many inches the roof rises for every horizontal foot. For example, a "four twelve" slope rises four inches every foot (or every twelve horizontal inches). Also called "pitch."

Slope transition — When a roof plane ties into another roof plane that has a different pitch or slope.

Soffit — The finished underside of the eaves/overhangs. Usually wood, metal or vinyl.

Square — 100 square feet. A 10' x 10' section would equal "one square."

Stair-step installation — A method of installing shingles where each course/row is installed a few inches shorter than the previous course/row of shingles. Thus, it serves as a combination of the "racking" (i.e., vertical) method and the purely rake-to-rake or end-to-end (i.e., horizontal) application method.

Starter strip — Narrow strips that are installed underneath the first course of shingles for the purpose of sealing down the bottom edge of the shingle at the eave. Standard "3-tab" shingles are usually modified to serve this purpose, while some contractors prefer to use factory-manufactured starter strips.

Steep slope — When the roof pitch exceeds 21/12. With extremely steeper slopes, additional fasteners are almost always necessary. Also, it is quite common for people in the roofing industry to refer to any roof pitch above 4/12 as a "steep slope" roof.

Step flashing — Flashing application method used where a vertical surface (i.e., chimney, dormer wall, etc.) meets a sloping roof plane.

Tab — The bottom portion of traditional "3-tab" shingles where the exposed surface of the shingle is separated by slots, normally cut at 12" intervals.

Tear-off — When all of the existing waterproofing materials (i.e., shingles, edge metal, felt paper, etc.) are removed down to the roof deck.

Three-tab shingle — The most traditional shingle style that is normally 12" x 36" in size with three equal-sized tabs along the exposed surface of the shingle.

Under-driven fasteners — A problem that occurs when a fastener is not installed flush to the shingle surface.

Underlayment — A layer of asphalt-saturated material that is installed on the main roof deck prior to the installation of shingles, providing additional protection for the roof deck.

Valley — Where two adjacent sections meet, forming a "V" that allows for water runoff.

Ventilation — The term used in roofing to describe the system that allows for the passage of air through or from an enclosed space.

Warm wall — The finished wall inside a structure. It is relevant to roofing in that it helps to determine how far up the slope of a roof (from the eave edge) special waterproofing underlayment (such as "ice and water shield") must go.

Woven valley — The method of installing valleys by laying one shingle over the other up the valley center, alternating from the course of one plane to the corresponding course on the other side of the valley.