Back-Nailing: The method of fastening the back or upper side of a ply of roofing felt or other component in a roof system so that the fasteners are covered by the following ply.

Barrel Roof: A roof configuration with a partial cylindrical shape to it.

Base Flashing (membrane base flashing): Plies of roof membrane material used to seal a roof at the vertical plane intersections, such as at a roof-wall and roof-curb junctures. (See also Flashing.)

Base Ply: The primary ply of roofing material in a roof system.

Battern: Also referred to as Purlins. Battern or Purlins can be 1″ x 2″ x 4′ wood strips nailed to the roof or rafters, upon which the roofing is attached. In some instances they are also steel lengths measuring about an inch or so wide that have an elevated middle where one screws the metal roofing into. Sometimes called ‘hat channel’ because of its shape. Batterns or purlins are attached to roof decking to give a secure base to anchor the roofing materials to because many OSB (chip board sheets appearing much like plywood) will not hold screws properly.

Bermuda Seam: A metal roof that has a step profile.

Bird Bath: Small, inconsequential amounts of water on a roof that quickly evaporates.

Bitumen: Any of various flammable mixtures of hydrocarbons and other substances, occurring naturally or obtained by distillation from coal or petroleum, that are a component of asphalt and tar and are used for surfacing roads and for waterproofing.

Bitumen-Stop: A continuous seal for preventing bitumen from leaking down into or off a building. Is constructed by extending the base sheet or other non-porous ply of felt beyond the edge of the field plies. It is then turned back onto the top of the system and adhered. See also Envelope.

Bituminous Emulsion: Bituminous particles suspended in water or other solution. See also Asphalt Emulsion.

Blind-Nailing: The use of nails so that they are not exposed to the weather in the finished roofing system. See Back-Nailing

Canopy: An overhang, usually over entrances or driveways.

Cap Flashing: A material used to cover the top edge of base flashings or other flashings. (See also coping.)

Caulk: A material with no elastomeric properties used for sealing joints.

Caulking: The act of sealing a joint or of material.

Chalk: A powdery residue on the surface of a material.

Chalk Line: (1) A string on a reel in a container that can hold chalk; (2) A line made on by pulling taut a string coated with chalk and snapping it.

Channel Flashing: Flashing with a built-in channel for runoff; used where roof planes intersect other vertical planes.

Cladding: A material used to cover the exterior wall of a building.

Cleat: A continuous metal strip used to secure two or more metal roof components together. Commonly used along with coping or gravel stop on tall buildings.

Clip: A small cleat. See Cleat.

Clipped Gable: A gable cut back at the ridge in a small hip configuration.

Closed-Cut Valley: A method of valley application in which shingles from one side of the valley extend across the valley while shingles from the other side are installed over the top of those and then trimmed back approximately 2 inches from the valley centerline

Construction Joint: A constructed joint where two successive installments of concrete come together.

Contact Cements: Adhesives used to adhere or bond roofing components.

Coping: the piece of material used to cover the top of a wall and protect it from the elements. It can be constructed from metal, masonry, or stone.

Copper: A reddish-brown element that conducts heat and electricity very well. It is also used as a primary roof material as well as a flashing component. Copper turns a greenish color after being exposed to the weather for a length of time and appears in the middle of the Galvanic Series.

Collar/Boot: Pre-formed flange placed over a vent pipe to seal the roof around the vent pipe opening. Also called a pipe boot.

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

Dome: A roof with a partial-spherical shape.

Dormer: A framed window unit projecting through the sloping plane of a roof. Pop up from the main roofline, like a small house with its own walls, roof and window. Roof dormers provide light, added space, and ventilation to the topmost spaces in the house.

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. Some eave trims have a built in drip edge. Trim that goes here is called “drip trim”.

Downpipe: A conduit for carrying water from a gutter, scupper, drop outlet or other drainage unit from roof to ground level. Also known as a Leader Pipe.

Eaves: the lower part of a roof that overhangs the walls. Trim that goes on these areas is referred to as “eave trim”, “eave flashing” or sometimes “drip edge”. (We use the term “eave trim”).

Fascia: Vertical roof trim located along the perimeter of a building, usually below the roof level. Its use can be either decorative or for waterproofing.

Fasteners: Devices used to secure roof system components.

Fiberglass Insulation: Insulation composed of glass fibers used to insulate walls and roofs. It can be rigid board or blanket insulation.

Flashing: Components used to seal the roof system at areas where the roof covering is interrupted or terminated. For example, pipes, curbs, walls, etc. all have special components that, when correctly installed, will help prevent moisture entry into the roof system or building.

Flashing cement: In the application of metal roofing, flashing cement is usually a clear silicone caulk (purchase the best grade available). This is used to further seal any potential leaks, usually at areas wherein flashing was applied. A small bead of flashing cement where the flashing comes in contact with a vertical wall is a good idea.

Gable: The upper portion of a sidewall that comes to a triangular point at the ridge of a sloping roof. Trim that goes on this part of a roof is called “gable or rake trim”. We use the term “gable trim”.

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-On-Hip Roof: A roof configuration with hips coming up from the eave corners that terminates into a gable roof.

Galvalume: Trade name for a protective coating composed of aluminum zinc.

Galvanize: To coat with zinc.

Galvanized Steel: Steel that is coated with zinc to aid in corrosion resistance. Galvanized steel for use in roofing should be Hot-Dipped Galvanized with a G-90 coating.

Girt: A horizontal beam place between support columns that is used for attaching wall cladding.

Gutter: A channel (usually sheet metal) installed along the downslope perimeter of a roof to convey runoff water from the roof to the drai.

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. This type of roof does not contain a gable(s).

HVAC: Acronym for Heating, Ventilating, and Air Conditioning.

Insulation: Material used to help maintain a certain temperature in a building by reducing the flow of heat to and from that building. See also Thermal Insulation.

Lean-to roof: A roof with one slope only that is built against a higher wall.

Low slope application: Method of installing roofing material on roof slopes between one and two inches per foot.

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. This type of roof contains no gables.

Mastic: See Asphalt Roof Cement

Metal drip edge: This refers to trim, usually gable and eave trim that has a slight bend at the edge which facilitates water runoff, away from the building. All our eave and gable trims contain this feature.

Material Safety Data Sheets (MSDS): Written descriptions of the chemicals in a product provided by the product’s manufacturer. MSDS also contain other information such as emergency procedures and safe handling.

Membrane: The portion of the roofing system that serves as the waterproofing material. Can be composed of one material or several materials laminated together.

Metal Flashing: Roof components made from sheet metal that is used to terminate the roofing membrane or material along roof edges. Metal flashings are also used in the field of the roof around penetrations.

NRCA: National Roofing Contractors Association.

Open valley: Method of roofing in which the roofing material on both sides of the valley is trimmed along a chalk line snapped on each side of the valley, leaving the valley flashing exposed. Metal roofing always has this feature.

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

Oil Canning: A distortion that may arise when a new roof is applied over an uneven surface.

Parapet Wall: That part of a perimeter wall that extends above the surface of the roof.

Penetration: Any object that pierces the surface of the roof

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.

Purlin: Horizontal lengths of material (wood or metal) that are affixed to the roof and to which the finished roofing material is affixed.

Purlins can be wood strips (1″ x 2″) or can metal and are usually a 1″ subgirt material preferably galvanized steel. Because the purlins elevate the new roof slightly they also contribute to your new roofing having airflow which can help dispurse temperatures in the heat of the day.

It’s sometimes necessary to use purlins over an old roof as the purlins give one the ability to do some “leveling” by using feathering strips or shims between the purlins and the irregularities of the old roof surface.

Here is an illustration of a Purlin Plan showing placement of the purlins on the roof:

PVC: Polyvinyl Chloride.

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 Cap: Material applied over the ridge or hip of a roof.

Ridge Vent: An exhaust venting device located at the ridge of a roof that works in conjunction with a starter or under eave soffit vent and is used to ventilate attics. Ridge vents and their cooperative starter or soffit vents should be installed at a 1:1 ratio in order to function properly.

Roof Jack: (1) A steel bracket fastened to the roof that is used to support toe boards. (2) A term used to describe a Pipe Boot or Flashing Collar.

Roof Slope: The angle made by the roof surface plane with the horizontal plane and expressed as the amount of vertical rise for every twelve inch (12″) horizontal run. For instance, a roof that rises four inches (4″) for every twelve inch (12″) horizontal run, is expressed as having a “four in twelve” slope; often written as “4:12.” Expressed as a percentage, the slope would be 33%, which is equal to 4 divided by 12. Also known as the Pitch of a roof.

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.

V

Valley: The internal angle formed by the intersection of two sloping roof planes to provide water runoff. Trim that goes on this area is called “valley trim”.

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 sleeve: See collar/Boot.

Viscosity: The resistance of a material to heat flow.

Volatile: That which readily vaporizes; evaporates quickly.

Water Guard: A turned up edge on valley metal or continuous wall flashing; used to prevent water migration under the roof system.

Waterproof: Being resistant to moisture infiltration.

Waterproofing: The treatment of a surface or structure in order to prevent the passage of water under hydrostatic pressure.

Windward: Facing into the wind.

Zinc: A bluish-white, lustrous metallic element that is brittle at room temperature but malleable with heating. It is used to form a wide variety of alloys including brass, bronze, various solders, and nickel silver, in galvanizing iron and other metals, for electric fuses, anodes, and meter cases, and in roofing, gutters, flashings, edge metals and also for various household objects. Atomic number 30; atomic weight 65.37; melting point 419.4 °C; boiling point 907 °C; specific gravity 7.133 (25 °C); valence 2.