APP Modified Torchdown Roofing
A high quality bitumen material combined with polymeric resins and reinforced with polyester matting. Impermeable to rainwater and resistant to damaging UV rays. Approximate service life of up to 20 years.
Asphalt
A dark brown to black substance found in natural beds and is also obtained as a residue in petroleum or coal tar refining that consists chiefly of hydrocarbons.
Asphaltic composition used for pavements and as waterproof cement.
Attic
The open space between the underside of the roof sheathing and the upper side of the ceiling directly below the roof.
Base Flashing
That portion of the flashing that is attached to, or rests on the roof deck to direct the flow of water on a roof, or to seal against the roof deck.
A material applied to the base of a wall extending above the roofline, as protection for the junction of the vertical wall and the roof.
Bitumen
Bitumens are mixtures of hydrocarbons of natural or pyrogeneous origin; or combinations of both, frequently accompanied by their non-metallic derivatives, which may be gaseous, liquid, or solid, and which are completely soluble in carbon disulfide. In the roofing industry, the work covers both asphalt and coal tar pitch.
Cant Strip
A beveled support used at the junction of the roof deck with a vertical surface, so bends in the roofing membrane that form the base flashings can be made without damage to the membrane.
Caulk
A compound used to fill joints, gaps, and imperfections.
Closed Valley
A valley in which the flashing is covered by a shingle membrane.
Condensation
The change from water vapor to liquid water, resulting from a drop in temperature of an air vapor mixture.
Coping
The cap or highest covering course of a wall, usually overhanging the wall, and having a sloping top to carry off water.
Counter Flashing
Strips of metal, roofing, or fabric inserted and securely anchored to the reglet or attached to a vertical surface above the plane of the roof, and turned down over the face flashing to protect the base flashing.
Course
A row of shingles that can run horizontally, diagonally or vertically.
Curb
A wall of wood or masonry built above the lever of the roof, surrounding a roof opening for a skylight, roof fan, or other equipment.
DeadLoad
The total weight of all installed materials and the constant weight of a roof used to compute the strength of all supporting framing members.
Deck
The top surface of a structure, serving as a substrate for the roofing membrane. Normally consists of plywood, boards, or other sheet materials such as oriented-strand board (OSB). Fastened with nails or screws.
Dormer
A separate smaller roofed structure that projects from a sloping roof to provide more space below the roof, usually containing a vertical window.
Downspout
A pipe conveying rainwater from a roof gutter to a drain.
Drip Edge
A modified L-shaped flashing used along the eaves and rakes. The drip edge directs runoff water away from the deck, fascia, eaves and siding .
Eave
The horizontal roof overhang that extends outward and is not directly over the exterior walls or the building interior. The horizontal lower edge of sloped roof.
Exposure
That portion of a shingle that is exposed to the weather.
Fascia
A wood trim board used to hide the cut ends of the roof rafters and sheathing. The gutter system is usually nailed to the fascia.
Fire Rating
The Underwriters Laboratories (UL) system for classifying the fire-resistance of various materials. Roofing materials are classified as Class “A”, “B” or “C”, with Class “A” materials having the highest resistance to fire originating outside the structure.
Fire Resistant
Material that is resistant to ignition by fire.
Fire Wall
Any wall built for the purpose of restricting the spread of fire in a building. Such walls of solid masonry or concrete usually divide a building from the foundations to about a meter above the roof.
Flashings
Metal strips used to form a watertight seal between the items butted up against the shingles. Flashing is used along walls, chimneys and dormers. Metal is usually 28 gauge galvanized sheet metal, but may be lead, copper, tin or aluminum. Prevents the seepage of water around any intersection or projection in a roof, such as vent pipes, chimneys, valleys and the joints at vertical walls.
Gable
The triangular end of an exterior wall from the level of the eaves to the ridge of a double-sloped roof.
Gambrel Roof
A type of roof which has it’s slope broken by an obtuse angle, so that the lower slope is steeper than the upper slope. A double-sloped roof having two pitches.
Gravel Stop
A gravel guard is used at the rakes and eaves of a built-up gravel coated roof.
Gutter
Through at the eaves of a roof to convey rainwater from the roof to the downspout.
Header
The beam into which the common joist are fitted when framing around a roof opening.
Head Lap
The overlapping of shingles or roofing felt at their top edge.
Hip Roof
A roof, which rises by inclined planes from all four sides of a building. The line where two adjacent sloping sides of a roof meet is called the hip.
Live Load
The total weight of all installed equipment and materials and all variable weight that will move across a surface.
Membrane
A waterproofing system of roof covering.
Overhang
That portion of roofing extending beyond the deck. As related to the roof structure, which extends beyond the exterior walls of a building.
Paparet
A low wall along the edge of and surrounding a roof deck. It is generally an extension of exterior building walls and above firewalls that usually extend about a meter or less above the roof.
Pitch
Height from the joist to the ridge divided by rafter length, which translates to rise in inches per horizontal foot or ratio of pitch. Ratio is a portion up to full pitch (24” in 12”).
Pitch Pan or Pocket
Usually a rectangular flanged metal collar placed around metal supports that project above a roof deck. The pitch pan is placed on top of the roofing underlayment.
Ponding
The collection of water in shallow ponds on the top surface of roofing. Certain roofs are designed for the ponding water to a shallow depth over the whole surface of the roof deck, to aid in summer cooling. Many flat roof systems void their warranties if ponding water sits on the deck for more than 48 hours.
Penentrations
Vents, pipes, stacks, chimneys – anything that sticks up through the roof deck.
Rafters
The lumber supports that make up the roof structure. Usually 2” x 12” lumber. The roof sheathing is nailed to the rafters. Serves as the supporting framing to which the roof deck is attached.
Rake
The inclined edge of a roof over a wall.
Reglet
A groove in the vertical wall adjacent to a roof surface, above the top of base flashing into which the metal counter flashing is placed and rigidly held in place; it is either formed in concrete or consists of a metal insert.
Ridge
The top edge of two intersecting sloping roof surfaces.
Ridge
The horizontal line where two opposite sloping sides of a roof join at the highest point of the roof, hip, or dormer. On double sloped gable roofs sometimes called the comb.
Ridge Cap
Formed shingles, shake or tile used to cover the ridge of a building.
Roof Drain
The termination or fitting at the roof of an interior drain or leader for draining rainwater from normally flat roofs.
Roof Insulation
Any medium or low density material used as part of the roofing system to reduce heat loss through the roof. A variety of insulation materials are being used including wood fibers, glass fibers, cork, plastics and poured lightweight.
Roof Span
Distance from outer wall to opposing outer wall of a building covered with a roof.
Roofing System
The waterproof roof covering, roof insulation, vapor barrier and roof deck as an entity.
Run
The horizontal distance between the face of a wall and the ridge of the roof.
Scupper
An outlet in the wall of a building or a parapet wall for drainage of overflow water from a floor or roof directly to the outside. Special scupper drains connected to internal drains are also sometimes installed at roof and wall junctions.
Side Lap
The horizontal distance one shingle overlaps the adjacent shingle in the same course; also the horizontal distance one sheet of roofing overlaps the adjacent sheet.
Slope
Measured by rise in inches for each 12 inches of horizontal run: A roof with a 4-in-12 slope rises 4 inches every foot.
Soffit
A board or sheet that extends from the fascia to the buildings siding and hides the bottom of an overhang. Soffit may or may not contain ventilation slots depending on the attic venting system used.
Starter Course
The first course of shingles installed on a roof, starting at the lower left edge of the eave.
Step Flashing
Metal shingles or plates used in a stair-step pattern under regular shingles. Step flashing is the recommended flashing whenever a wall or chimney is above the roof line.
Square
The common measurement for roof area - 100 square feet (10’ x 10’)
Tab
Weather exposure surface of a shingle between the cutouts.
Truss
A combination of members such as beams, bars and ties, usually arranged in triangular units to form a rigid framework for supporting loads over relatively long spans as in wide span roof construction. Most typical are engineered components which have supplemented rafters in many newer houses. They are designed for specific applications and cannot be cut or altered in any way.
Underlayment (15, 30 and 40)
Asphalt or coal tar saturated felt weighing approximately 15, 30 or 40 pounds per 100 square feet. Typically a mat of organic or inorganic fibers, providing a secondary layer of protection for the roof deck.
Valley
The horizontal line formed along the depressed angle at the bottom of two inclined roof surfaces. Formed at the intersection of two sloping roof surfaces.
Vent
An outlet for air; vent pipe in a plumbing system; a ventilating duct.
Vent Pipe
A vertical pipe providing an escape for foul gasses from a sanitary fixture. For a number of fixtures the vent pipes lead into a larger vertical pipe to the outside through the roof called a vent stack.
Water Vapor
Moisture as a gas in air. Warm air can hold more water vapor than cold air. Water vapors in the air create a pressure much like any other gas. Cold air has a relatively low vapor pressure.