Our hope is that when you speak to a roof contractor, either us or another company, that you will be able to understand some of the terminology used. By including this glossary on our site, we sincerely hope you obtain a little bit of knowledge and understanding about your roof system. The better informed you are, the better choices you can make regarding your roof.
Ability of the roof material to resist being worn from abrasive contact, such as foot traffic, flying debris, tree limbs, mechanical equipment, etc
Capability of material to accept quantities of liquid and gas, usually water
To bond two surfaces together
The state and degree of attachment between two surfaces
A bonding substance that keeps two surfaces attached
Crushed stone or slag, or water worn gravel used to top a built up roof; any granular mineral material
The effect of the weather and environment have on exposed material for a period of time
Rooftop fungus causing dark brown or black stains
Resembling the cracks of an alligator hide on the surface of bitumen built up roof; the cracks may or may not go through the surface of the bitumen
Sheet steel with a layer of aluminum to prevent rusting
Metal sometimes used for flashing and metal panels that does not rust
Air temperature
Roofing nails driven in at an angle and not parallel to the roof deck
American National Standards Institute
Atactic polypropylene; a modified bitumen membrane that can be smooth or granulated and is typically installed by torch down, but may also be applied by cold process adhesives
Amount of material applied per unit area
Metal flashing used at chimney fronts; metal flashing used where a sloped roof and wall or steeper sloped roof meet
Metal roof paneling usually requiring a solid deck underneath and a slope to shed water off
Also known as dimensional shingles; shingles that provide a three-dimensional appearance
Used to separate large roof areas to accommodate building movement or roof systems with incompatible materials; may used to assist in the installation of a tapered insulation system; is a single or double wood member attached to a properly flashed wood base plate anchored to the roof deck
Asphalt Roofing Manufactures Association
A group of natural, fibrous impure silicate minerals and materials used to resist heat and corrosion
American Society of Home Inspectors
A black or dark brown material obtained through petroleum or crude oil processing used in various types of roofing materials
Used as underlayment; felt paper that has been saturated with or coated with asphalt
Asphalt based primer used to ready material for asphalt sealant
Can be used for temporary roof repairs on asphalt based flat roofs; is a mixture of solvent based bitumen, mineral stabilizers, other fibers, and/or fillers; is trowel grade and used on asphalt compatible materials to waterproof; is divided into two standards: ASTM D2822 is applicable to material containing asbestos; ASTM D4586 is applicable to asbestos free material; can be classified as Type I or Type II; Type I is self-sealing, adhesive and ductile; is also known as plastic cement, mastic, blackjack, roof tar, bull; Type II is generally has a high softening point and low ductility; is also known as vertical grade flashing cement
A paper felt or reinforced fiberglass mat coated with asphalt-coating with mineral granules embedded on the weather exposed side
Formerly known as American Society for Testing and Materials; develops and designates voluntary standards used worldwide to improve product quality, safety, and consumer confidence
Open space above the ceiling and immediately below the roof deck on steep-sloped roof systems
Also known as blind nailing; the practice of driving nails or fasteners in the back portion of concealed roofing ply, steep roofing unit, or some other roofing component so that the fasteners are covered by the next ply and are not exposed to the weather; also used to prevent slippage in hot-mopping
Rock, aggregrate, or pavers placed on single-ply roofing membranes to hold in place
Initial coating in a series of coatings
First ply of roofing in a roof membrane or roof system
Initial sheet or ply in multi-ply built up and modified bitumen roof membrane systems
A plastic, wood, or metal strip fastened as to hold up roof membranes up at walls or hold base flashing in place; strip of wood used to set in or over the deck; a cap or cover; a metal closure set over or covering the joint between metal panels
Typically horizontal beam on on a roof structure that holds the roof loads; there are three types: simple, continuous, and cantilever
Generic term for any material made of bitumen, typically asphalt and coal tar
Treated with or containing bitumen
A pocket of air trapped caused by water vapor or gases in between layers of membranes, between felt and membrane, or between the substrate and membrane
Wood built up around curbs, drains, and other penetrations that serve to support a curb, as a wood nailer for membrane attachment, or to strengthen the deck around an opening
When high winds rip shingles or part of a shingle off the roof
Two subjects held together by adhesive or cohesive forces
An adhesive applied to a substrate and next layer to create a bond
Flexible material, usually in a particular shape, used to seal a penetration; flexible material used to create a closure, typically on inside and outside corners, usually an issue for roof repair
Also known as a metal brake; a piece of equipment used to bend and form metal; can be hand or power-activated machinery
Use of a broom or squeegee to smooth a membrane ply to adhesive or bitumen under the membrane to insure proper contact
Tented displacement of roof membrane or shingles usually occurring over insulation or deck joints
Published designations and ordinances by designated jurisdictions that prescribe design loads, the quality of material, construction details, procedures, building locations, maintenance, use, and occupancy in the area that the code has been adopted
Package of shingles or shakes
Built up roof membrane; a multi-ply roofing system where semi-flexible membrane or felts are applied with alternating layers of bitumen; typically the top layer is mineral aggregate and bitumen, liquid applied coating, or granulated cap sheet
Lower edge of shingle, tile or shake
When two adjacent and separate sections of material meet and form a joint
Sealant tape sometimes used at end laps and metal roof seams, some sheet metal joints, and other sealant applications
Overhanging roof structure over entrances and doors
Triangular or beveled strip of wood, wood fiber, perlite, or other material that is used under flashing to modify the angle where the membrane meets a wall or curb
Typically metal piece used to cover the upper edges of base, wall, or primary flashing
Granulated sheet used as the top ply of built up roof membrane
Used in all areas of roofing, including roof installation, roof maintenance, and roof repairs for sealing a joint, juncture, seam, crack, or void with caulk to make them watertight
Line made by snapping a string covered in colored chalk, a chalk box; used to align roof material during installation
When certain ingredients in coatings, paints, and other materials degrade or migrate out of the material
Stone or masonry structure that projects out of the roof that provides ventilation for smoke and flue gases
The horizontal or inclined member of a truss that resists bending
A strip, plate, or angled metal that serves to secure two or more components together, such as when coping metal attaches to the cleat
Shingle valley installation where shingles from one side completely cover the valley and are then trimmed back to match the valley lines
A layer of material applied by brush, roller, or spray used for waterproofing, further roof protection, and decoration
Degree of bonding a material has to itself
Roof membrane installed with alternating layers of cold applied roofing cement and a top layer of cold applied coating or cap sheet
Metal flashing used around vent pipes
Water vapor and other gases convert to liquid as the temperature lowers
A covering piece of a wall, sometimes secured with fasteners in the back and cleat under the front
Formed metal that protects and covers the upper edge of base flashing that is secured into a wall, curb, or pipe
A row of shingles or layer of roof material
Fracture in roof membrane
Network of fine cracks in roof membrane or coating
Elevated area on a roof to divert water around a chimney or curb, or away from a wall or expansion joint
When air moves through a roof cavity between vents
Also known as crow’s nest; small roof structure that sets on the ridge or peak of the main roof
A curl in shingles or shakes
Process from heat, chemicals, pressure, or weatherization that causes material to form permanent molecular linkages
Open portion between the tabs of a three tab shingle
No slope; absolutely horizontal
Rooftop loads, such as mechanical or HVAC equipment, that does not move
Structural surface or substrate that roof material is applied
Separation of the plies or laminated layers of a component or system
Temperature that water vapor begins to condensate
Half circle shaped roof
Raised projection that extends out of a sloped roof, many times for the purpose of placing a window
A conduit that drains water from scuppers, gutters, or conductor heads off the roof
Similar to a sink drain, it collects and directs water off the roof, sometimes the cause for a roof repair and must be maintained regularly
Installed metal lip that keeps shingle edges off the roof deck and extends the shingles over eaves and gutters; metal flashing on the lower edge of a roof that controls the direction of dripping water
Wind or moving load on a roof
Projecting roof edge that extends past the outside wall
Process where granules are pressed onto shingles or coating, or where hot bitumen or adhesive is pressed onto felt, fabric, or mat
When the end of rolled membrane is overlapped by the next sheet
Ethylene Propylene Diene Monomer; also known as rubber roofs; this system can be ballasted, mechanically attached, or fully adhered
Structural separation allowing free movement between two buildings to avoid roof system damage
Any nail left exposed to the environment without sealant or being covered
Part of roof system left exposed to the environment and weather
Small sized dormer, usually having an arched curved
Reinforcing inorganic or organic thread, filaments, or yarn used in certain membranes
Mutual company that researches and classifies roof systems on fire resistance and wind uplift resistance
Seam or splice made by the manufacturer
A board or metal running horizontal under the roof edge
Any nail, staple, screw,cleat, bolt, clip, etc that is used to secure roofing material or components
Organic, fiberglass, asbestos, or polyester sheet used as a waterproofing layer under the primary roofing material
Metal sleeve around a gutter spike
Insulation made of fiberglass, that can be blanket or rigid type; rigid insulation boards are used with flat and metal roofs
Main portion of the roof, not to include the perimeter or flashing areas
A half cylindrical opening or void in a lap edge or seam, or at the cut edge of a shingle
A substance added to reduce or retard material from burning
Rigid metal pan used around flashing pieces, such as skylight flange, flashing boot, chimneys, etc
System or material used to seal and waterproof around any roof penetration
Trowel grade Type II roof cement that may include organic or inorganic fibers that allow it to be used on vertical surfaces; also called vertical grade
Flashing used to seal pipes and other roof penetrations; also called roof jack or flashing boot
Top layer of aggregate embedded bitumen on a built up roof
Also known as water test; practice where a controlled amount of water is used to test if a portion of a roof is watertight; sometimes used to find roof leaks
Traditional roof style; triangular portion under the sloping roof and above the eave line at the endwall of a building
Steel coated with zinc to resist corrosion
Also called a barn style roof; a roof with two slopes on one side
Aggregate used to surface shingles, cap sheets, and other granule-surfaced roof material
Small rounded rock that eroded naturally and is used as aggregate
Metal flange at the roof edge that keeps aggregate from washing off the roof
Channeled trough or duct installed on the downslope perimeter of a roof to collect and divert rainwater away from the building
Method of sealing shingles on steep slopes, installing in cold weather, in high wind areas, and when shingle bonds have been broken, such as when doing a repair
Method of melting and fusing overlapping seams together by heat and pressure
Metal folded back on itself to reinforce or create a safe edge
When a shingle is nailed above the manufacture’s specified nail location
The down slope ridges on hip roofs
Roof with no vertical ends, that rises by inclined planes coming together at a peak and four separate hip legs
Term for hot bitumen
Heating, venting, and air conditioning equipment
Mass of ice or snow that melts and re-freezes at eave areas, forcing water and ice to back up under the roofing material
Ability of roofing material to resist impacts, such as puncturing from falling objects and foot traffic
To saturate or coat with a liquid material, such as bitumen or coating
Slope of a roof expressed by the number of vertical units of rise per horizontal units of run
Method to locate wet or moist insulation by infrared camera
Individually separate shingles that are mechanically attached to each to provide wind resistance
Wooden or metal beams arranged in a parallel fashion from wall to wall to support a roof, ceiling, or floor of a building
Imperfection in fabric construction that causes surface irregularities
Also known as dimensional shingles and architectural shingles; shingles made from two separate pieces and are then laminated together
The part of roofing component that overlaps the same or another component
Roof cement made to adhere to overlapping membranes or asphalt roll roofing
Seamed, sealed, or bonded overlapping materials
Soft metal used for certain flashing
Temporary loads, such as snow, rain, wind, people, installation equipment, etc, that the roof must be designed to support
Membrane that is not attached to the substrateexcept at the perimeter and penetrations, but is held down by ballast
A nearly vertical decorative roof on the perimeter of a building
Flashing cement or asphalt mastic
General term for certain rolled material and base material of shingles
When roofing membrane is attached to a substrate by fasteners, with plates or batten
Flexible or semi-flexible roofing material used in low slope and flat roofs to watertight the roof; examples are TPO, PVC, modified bitumen, EPDM
See flashing; flashing typically made from sheet metal for coping, step flashing, counterflashing, riglet metal, etc.
One mil is equal to 0.001 inches; used to indicate how thick a roof membrane is
Mold in early stage; fungal growth caused in damp conditions
See granules; aggregate used to surface shingles, cap sheets, and other roof materials
Roofing sheet that is surfaced with mineral granules, either on one side or both
Joint made by joining two diagonally cut pieces of wood so they produce a 90 degree angle
Rolled bitumen roofing membrane with one or more polymer included, such as atactic polypropylene (APP), that can be torched down or applied by cold process, or stryene butadiene stryene (SBS), which can be heat welded or applied by cold process
Method of applying hot bitumen, with either a mechanical applicator or by a hand mop
A mixture of sand, limestone, mortar, and water that holds bricks together
A painted line on laminated shingles to aid the installer in drive nails in the proper placement
When a nail is not driven in fully, or backs out off the deck due to building movement, and sits above the roof deck; these nails can sometimes pop through the roof material or shingle and cause a roof leak
Synthetic rubber, that can be made into rolls for flashing, cement, or coating to watertight
Used when installing a second shingle layer to cover 3 tab shingles with larger shingles, such as architectural shingles, so to avoid the underlaying shingles cupping
Method of temporarily sealing a roof membrane to protect from water intrusion until the installer can come back, usually the next day, to finish the roof
National Roofing Contractors Association
Method valley installation on a shingle roof where metal is used down the valley center
Any material made from plant or animal matter
An organic base material saturated with asphalt and used as underlayment between the substrate and shingles or roofing material
Mat made from recycled wood pulp and paper
Shingles made with an organic base mat
Orientated Strand Board; made from wood chips and lamination glues and used as roof decking
Occupational Safety and Health Administration; government administration that sets rules and regulations to provide safe working conditions
When fasteners are driven too far that the roofing material rips or is punctured
When shingles or shingle courses are placed higher than their intended exposure; may cause shingles to blow off or roof leaks
Flat bottom part between the ribs of a roofing panel
Any part of a perimeter wall that is entirely above the roof
Any object, such a pipe, vent, electrical conduit, etc, that passes through the roof
Light weight, insulating aggregate used in concrete insulation and preformed perlitic insulation board
Installation of a roof system during two or more separate time intervals
A form of flashing around a penetration that is filled with bituminous or polymeric sealants to help reduce the risk of roof leaks
Type I trowel grade roof cement used for low slope applications
The physical property of material being flexible or bendable
A layer of roof material, such as felt, ply sheet, or membrane, in a roof system
Water that is sitting on a roof and has not drained off completely
A flat roof having sufficient slope to ensure drainage of water off the roof within 48 hours
Liquid applied solution used to improve the adhesion and increase the strength between two surfaces bonded together
The extent of a roofing material to be able to withstand the action of sharp objects without becoming perforated
Secondary horizontal structural member that supports the rafters of the roof by transferring the load from the primary framing
Term for the size of the dabs in hand sealing shingles during roof repairs, extreme steep slope, and high winds; based on the size of a U.S. quarter
Unrecommended method of installing shingles straight up the roof
One of a series of sloped beams that supports a sloped roof and its loads
A thin cut in a masonry wall used to insert a flashing component, such as a reglet
Sloped edge of a gable style roof plane
Starter strip, bleeder strip; first course of shingles installed along the rake edges that is trimmed
Covering an existing roof system with a new one without tearing the original one off
Metal receiver between a wall and roof used for attachment of counterflashing
Membrane that has been strengthened with one or more reinforcing material
Ratio of the weight of moisture in a given volume of air
Plastic strip installed on the back of shingles used to keep the shingles from sticking to each other during shipping and installation
Removing the existing roof system to replace it with a new one
Highest outer horizontal point that two sloped roofs meet
Roof material used to cover a roof ridge
Shingles specifically manufactured to install on the ridge of a shingle roof
The last or top row course of shingles, tiles, slate, shake, or other roofing material that covers the ridge
Vent located on the roof ridge that allows warm and moist air out of the attic; most are prefabricated shingle over types; typically the ridge needs to be cut during installation to allow for an opening for the air to escape
Roof components assembled together to make a complete roof system
Metal bracket nailed under shingles, shake, etc. used to support toe boards on steep roofs
Also know as airhawks, box vents, mushroom vents, soldier vents; rectangular shaped roof vents
Roof area having four separate edges
Act of fixing roof damage or a roof leak
Angle of a roof, expressed by the ratio of units of vertical rise to horizontal length
Horizontal component of slope
Small, raised structure composed similar to a hip roof or pyramid constructed to divert water; may be located between drains, valleys, or behind a chimney
Area of roof is lower than the rest of the roof due to damaged decking or building movement
Felt that has been saturated with bitumen
Exposed section of double thickness on certain shingles used to imitate a wood shake look
Also known as conductor heads, collector heads, leader heads; component used in roof drainage to collect rainwater and channel it through a downspout
A hatch that provides access from the inside of a building to the roof
Watertight a roof component or roof system
A mixture of polymers, fibers, fillers, and pigments used to fill and seal joints that cures to a solid
The force required to separate a roof membrane seam
Also known as peel and stick; a membrane that can adhere to a substrate without additional adhesives
Fastener that allow drilling and fastening to be done at the same time in one application
Factory-applied adhesive installed on the back of a shingle with the purpose of bonding to the overlaying shingle once heat has activated the sealant
Edge that is different from the rest of the material to resist fraying or for overlapping seams
Overlapping seam typically in granule surfaced cap sheets where the edges are not granulated
Slight difference in color of roof materials, such as shingle colors
A roof with only one roof plane that does not tie into any other roofs
Individual roof covering that is installed in courses with the above courses overlapping the shingles below; to apply shingles to a roof
Installation of shingles to a roof
Where one roll overlaps the roll beneath it in a continuous longitudinal fashion
Vertical roof plane meets a vertical wall
Framed horizontal bottom of an opening, such as a window
A roof accessory mounted on a rooftop curb designed to admit light
Hard metamorphic rock used as dimensional stone for sloped roofs
Movement of roof membranes on a slope that exposes the lower plies or even base sheet
Angle of incline, expressed by the number of vertical units of rise per horizontal units of run
A series of devices installed on a roof to hold snow to prevent snow or ice slides from sliding off the roof
A live or environmental load; load on buildings caused by snowfall
Underside of the exterior overhanging of a building
Air inlet source located under the eaves, roof edge, or soffitt
Sanitation pipe that penetrates the roof
When the outer layer of masonry or bricks begin to break or flake away
Small block laid on the ground under a downspout to avoid soil erosion
Tear in roof material from substrate or material stress
Act of removing roof aggregate, particularly build up roofs, by scraping and chipping
100 square feet of a roof area
Vertical outlet designed to relieve the moisture vapor pressure from between the substrate and roof membrane
Chromium, nickel, or copper added to steel for the purpose of resisting corrosion
Overlapping or interlocking seam at an upturned rib on a metal roof
Felt or membrane used at the perimeters of a roof area on mechanically attached roof systems or at the edge of the roof on shingle roofs
First course of roofing installed; roll roofing or shingle strips applies at the eave line to fill gaps between cutouts and joints
Any load on a roof that does not change position or size over time
Individual pieces of metal overlapping each other used to flash walls, chimneys, and dormers
Structural deck or insulation that roofing membrane is applied
Depression made around a roof drain or scupper box to aid in drainage
Loads that are added to existing loads
Bottom exposed portion of strip shingles separated by cutouts
Insulation providing a gradual transition from one level to another with the purpose of installing crickets or building the roof up around curbs
Removal of the existing roof down to the deck
Taking a sample of a roof to diagnose the condition of the membrane or the materials on the existing roof system
Resistance that a material has to heat flow
Stress applied to roofing material from sudden temperature change
Roofing membrane or material that extends through a wall to direct water away from the wall
To form a waterproof seal at a termination or flashing; act of using rope or other device attached to a secure point on a roof and the other end attached to a harness worn by the roofer to protect them from falling
Type of joint made by one piece having a cut groove and the other an outward tongue; used so adjacent planks fit in alignment to form a uniform deck
When a roof plane meets another roof plane with different slopes
Underwriters Laboratory; non-profit organization that tests, inspects, and classifies products for safety and efficiency
Form of radiation invisible to the human eye, situated just past the violet end of the visible spectrum; over time, ultraviolet radiation can cause roof material to age and degrade
When a fastener is not fully driven flush; if not corrected, underdriven fasteners can pop through the roof material and cause roof leaks
Sheet installed over the roof substrate and under the roof system, typically in steep slope roofs; used to provide a secondary layer of weather protection
V shaped depression on a roof caused from the intersection of two sloping roof planes
Moisture laden air
Movement of water vapor from an area of a higher amount of water vapor pressure to an area of a lower amount of water vapor pressure
Material installed to restrict or impede water vapor moving through a roof or wall assembly
An opening designed to allow for the passage of air and water vapor from inside a building to the outside
A naturally occurring mineral used in attic and concrete insulation
Written promise to the building owner concerning the roof system and roof materials
Extremely tacky compound used to seal and waterproof with compression type terminations
Modified bitumen based underlayments used to seal wood decks and waterproof critical areas, such as eaves and valleys
Treatment of material, a surface, or a structure to prevent the intrusion of water
Small opening to allow the drainage of water from a building component, such as a skylight or brick wall
Moisture moved by capillary action
Force caused when wind pressure is greater below a roof than above the roof; if this force is greater than the roof is designed for, the roof could be lifted off the building
Method of valley construction where shingles extend acroos the valley and each alternate course overlaps the other