A B C D E F G H I J K L O P R S T U V W Z
If you would like to add a term to the list please feel free to e-mail us by clicking on the link above and we will add it for you.
Absorption: The act or process of retaining foreign particles such as gas or liquid without transmission of these particles.
Acid Etch: (1) The use of a strong acid to remove the surface of concrete thereby exposing the aggregate. (2) The use of a strong acid to etch the surface of material such as metal in order for that material to accept a primer or Spray Polyurethane Foam.
Acrylic Coating: A coating system with an acrylic resin base.
Acrylic Resin: Polymers of acrylic or methacrylic monomers often used as a latex base for coating systems.
Adhere: The clinging of one surface to another; either molecularly or otherwise.
Adhesion: The state of adhering
Aggregate: A surfacing or ballast for a roof system. Aggregate can be rock, stone, crushed stone or slag, water-worn gravel, crushed lava rock or marble chips.
|
|
Alligatoring: The cracking of the surfacing bitumen on a built-up roof, producing a pattern of cracks that resemble an alligator’s hide. |
Aluminium: A non-rusting metal used in roofing for metal roofing and the fabrication of gutter and flashings.
Alvadac: Trade name for a range of EPDM products
Ambient Temperature: The temperature of the air.
Anchor Bolts: Bolts which fasten columns, girders or other members to concrete or masonry.
Angle Iron: A piece of iron that forms a right angle.
Application Rate: The rate at which a material is applied per unit area.
Apron Flashing: A flashing located at the low end of a curb or penetration.
Architect: A tradesman who designs and produces plans for buildings, often overseeing the building process.
Architectural Panel: A metal roof panel that usually requires solid decking underneath.
Area Divider: A flashed assembly usually extending above the surface of the roof that is anchored to the roof deck. It is used to relieve thermal stresses in a roof system where an expansion joint is not required, or to separate large roof areas.
Asbestos: An incombustible fibrous mineral form of magnesium silicate formerly used for fireproofing and sometimes used for the reinforcement of roofing materials.
Atactic Polypropylene: A group of high molecular weight polymers formed by the polymerization of propylene.
Attic: The open area above the ceiling and under the roof deck of a steep-sloped roof.
Auger: Mainly used in carpentry, a wood-boring tool used to bore holes.
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.
Back-Surfacing: A fine mineral material on the back side of roofing materials such as roll roofing to keep them from sticking together while packaged.
Ballast: A material installed over the top of a roof membrane to help hold it in place. Ballasts are loose laid and can consist of aggregate, or concrete pavers. The ballast used for EPDM is generally above 10mm diameter and is smooth (No Quarry Gravel) river gravel is usually the best.
Bar Joist: See Steel Joist.
Barometer: Instrument for measuring atmospheric pressure.
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.
Base Sheet: An asphalt-impregnated, or coated felt used as the first ply in some built-up and modified bitumen roof systems.
Batten: (1) A strip of wood usually fastened to the structural deck for use in attaching a primary roof system such as tile; (2) A plastic strip, wood strip, or metal bar which is used to fasten or hold the roof and/or base flashing in place, A.K.A. Termination Bar, also used for fixing trims to the perimeter of low pitch roofs.
Beam: Structural support member (wood, steel, concrete) that transfers weight from one location to another.
Bermuda Seam: A metal roof that has a step profile.
Bird Bath: Small, inconsequential amounts of water on a roof that quickly evaporate.
Bird Screen: Wire mesh installed over openings in order to prevent birds from entering a building or roof cavity.
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.
Bituminous Emulsion: Bituminous particles suspended in water or other solution. See also Asphalt Emulsion.
Bleeder Strip: A starter strip placed along rake edges for use in asphalt shingle roofing. See also Rake-Starter.
Blind-Nailing: The use of nails so that they are not exposed to the weather in the finished roofing system.
Blister: A pocket of air trapped between layers of felt or membrane. Blisters are usually caused by water or other foreign substances.
Blocking: Pieces of wood built into a roof assembly used to stiffen the deck around an opening, support a curb, or for use as a nailer for attachment of membranes or flashing.
Blue prints: Architectural plans for a building or construction project.
Bond: The force(s) holding two components in positive contact.
Bonding Agent: A chemical agent used to create a bond between two layers.
Boot: A piece of material preformed to protect roof penetrations from dirt, moisture and other foreign and/or damaging substances.
Bow (Warp): A curve, bend or deviation from being flat.
Bridging: When membrane is unsupported at a juncture.
British Thermal Unit (BTU): The heat energy necessary to raise the temperature of one pound of water one degree Fahrenheit, a joule.
Buckle: A long, tented displacement of a roof membrane. Can occur over insulation and deck joints.
Built-Up Roof Membrane: A roof membrane consisting of layers of bitumen, which serves as the waterproofing component, with plies of reinforcement fabric installed between each layer. The reinforcement material can consist of bitumen-saturated felt, coated felt, polyester felt or other fabrics. A surfacing is generally applied and can be asphalt, aggregate, emulsion or a granule-surfaced cap sheet.
Butt Joint: Where two separate, adjacent pieces of material abut.
Butterfly roof: A roof with two opposing pitches meeting in the middle
Butyl: A hydrocarbon radical, C4H9. Butyl has a rubber-like consistency, is formed from the copolymerisation of isobutylene and isoprene and is used primarily in sealants and adhesives.
Butyl Rubber: A butyl-based, synthetic elastomer.
Butyl Tape: A sealant tape used in numerous sealant applications such as sealing sheet metal joints.
Calender: A machine used to laminate sheeting or for applying coating with a specified thickness and/or surface attribute.
Calendering: A specific process used to manufacture some membranes such as PVC.
Camber: A slight convex curve of a surface.
Canopy: An overhang, usually over entrances or driveways.
Cant: (1) Short for Cant Strip; (2) The act of installing foam at a right angle adjunct.
Cant Strip: A triangular-shaped strip of material used to ease the transition from a horizontal plane to a vertical plane. Cant strips can be made of wood, wood fibre, perlite, or other materials.
Cap Flashing: A material used to cover the top edge of base flashings or other flashings. (See also Coping.)
Cap Sheet: A granule-surfaced membrane often used as the top ply of BUR or modified roof systems.
Capacitance Meter: A device for locating moisture within a roof system by measuring the ratio of the change to the potential difference between two conducting elements that are separated by a non-conductor.
Catalyst: A substance that effects a chemical reaction and/or the rate at which a chemical reaction takes place. In roofing, catalysts are used in fibreglass roofing.
Cathodic: metals low in the Galvanic Series.
Caulk: A material with no elastomeric properties used for sealing joints.
Caulking: The act of sealing a joint or of material.
CCF: 100 cubic feet.
C-Channel: A structural framing member that, when viewed cross-sectionally, has the shape of a "C".
Cellulose: A complex carbohydrate, (C6H10O5)n, that is composed of glucose units, forms the main constituent of the cell wall in most plants, and is used in the manufacturing of organic roofing materials.
Cellulose Insulation: Ground up newspaper that is treated with a fire retardant.
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.
Chemical Resistance: A materials ability to retain its properties when it comes into contact with certain chemicals.
Chlorinated Polyethylene1 (CPE): CPE is a flexible material with high tear strength, good chemical resistance and patency towards UV radiation. As a result of the high chlorine content (typically 30%) it is inherently difficult to ignite, but releases hydrogen chloride during combustion. It suffers from an extremely high permeability to gas. Resistance to most inorganic chemicals is generally good, while resistance to hydrocarbons increases with increasing chorine content. The material is used mainly as an impact modifier for PVC and, to a lesser extent, LDPE and HDPE film.
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.
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 centreline.
Closure Strip: A material used to close openings created by joining metal panels or sheets and flashings.
Coal Tar Bitumen: A proprietary trade name for Type III coal tar used in dead-level or low-slope built-up roofs. It is not for use in roofs exceeding ¼" in 12" (2%) slope.
Coarse Orange Peel Surface Texture: A surface showing a texture where nodules and valleys are approximately the same size and shape. This surface is generally acceptable for installing a protective coating.
Coating: A layer of material that is spray, roller, or brush applied over a surface for protection or sometimes decoration.
Cohesion: Mutual attraction by which the elements or particles of a body or substance are held together.
Cold Applied: Products that can be applied without heating. These are in contrast to products which need to be heated to be applied.
Cold Patch: A repair done with cold applied material.
Collar Beam: A tie that stops a pitch roof from spreading, connects similar rafters on opposite sides of the roof.
Column: A vertical structural member placed on a footing or foundation used to support horizontal above-ground building components.
Combing Ridge: A term used to describe an installation of finishing slate at the ridge of a roof whereby the slates on one side project beyond to the apex of the ridge.
Combustible: Capable of igniting and burning.
Compatible: Two or more substances which can be mixed or blended without separating, reacting, or affecting either material adversely
Condensate: The liquid resulting from condensation.
Condensation: The conversion of water vapour to liquid state when warm air comes in contact with a cold surface. (See also Dew Point.)
Conduction: The transmission or conveying of something through a medium or passage, especially the transmission of electric charge or heat through a conducting medium without perceptible motion of the medium itself.
Construction Joint: A constructed joint where two successive instalments of concrete come together.
Contact Cements: Adhesives used to adhere or bond roofing components.
Convection: Transfer of heat by movement of heated molecules.
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 colour after being exposed to the weather for a length of time and appears in the middle of the Galvanic Series.
Cornice: A horizontal projecting part that crowns the wall of a building.
Corrugated: Folded or shaped into parallel ridges or furrows so as to form a symmetrical wavy surface.
Counter Batten: Wood strips installed vertically on sloped roofs over which horizontal battens are secured.
Counterflashing: Formed metal sheeting secured to walls, curbs, or other surfaces, for use in protecting the top edge of base flashings from exposure to weather.
Cove: In roofing, a heavy bead of sealant material installed at the point where vertical and horizontal planes meet. It is used to eliminate the 90° angle. See also Fillet.
Cover Plate: A metal strip sometimes installed over the joint between formed metal pieces.
Coverage: The surface area covered by a material.
Crack: A separation or fracture occurring in a material. See also Split.
Crazing: A series of hairline cracks in the surface of a weathered material, having a web like appearance.
Creep: Movement of roof membrane causing the roof system to be deformed
Cricket: A roof component used to divert water away from curbs, platforms, chimneys, walls, or other roof penetrations and projections. See also Saddle.
Cross Ventilation: The effect of air moving through a roof cavity between vents.
Curb: (1) A raised member used to support skylights, HVAC units, exhaust fans, hatches or other pieces of mechanical equipment above the level of the roof surface, should be a minimum of eight inches (8") in height; (2) A raised roof perimeter that is relatively low in height.
Cure: A process by which a material is forms permanent molecular linkages by exposure to chemicals, heat, pressure, and/or weathering.
Cure Time: The time necessary to effect curing.
Curing Agent: A material additive that alters chemical activity between the components resulting in a change in the rate of cure.
Curing Compound: A liquid that is applied to newly installed concrete which slows water loss while curing.
Damp proofing: Treatment of a surface or structure to resist the passage of water in the absence of hydrostatic pressure.
Dead Level: Refers to a roof with no slope or pitch.
Dead Loads: Permanent, non-moving loads on a roof resulting from the weight of a building’s components, equipment, and the roof system.
Deck: The structural component of the roof of a building, which provides the substrate to which the roofing system is applied.
Decking: See Deck.
Deflection: The downward displacement of a structural member under load.
Degradation: A decline in the appearance, structure, or properties, of a material or substance.
Delamination: Separation of laminated layers of a material or system.
Dew Point Temperature: The temperature at which water vapour turns to liquid in cooling air at the existing atmospheric pressure and vapour content.
Diaphragm: A type of structural roof deck capable of resisting shear that is produced by lateral forces such as wind or seismic loads.
Diffusion: The movement of a substance such as water vapour from regions of high concentration to regions of lower concentration
Dimensional Stability: The ability of a material to retain its current properties and to resist a change in size resulting from exposure to temperature changes and moisture.
Dome: A roof with a partial-spherical shape.
Dormer: A framed projection through the sloping plane of a roof. (See Fig1 )
Double Coverage: Installing roofing so that there are twice the materials used resulting in a double layer of roofing.
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. (See Fig 1)
Downspout: See Downpipe. (See Fig 1)
Drain: a device used to carry water off of a roof.
Drawing outline: A top view drawing of a building or roof showing the roof perimeter drawn to scale.
Drip Edge: A device designed to stop water running back under an overhang. A fibreglass (or steel) flashing formed at a 90º angle that is placed along the outer perimeter of steep sloped buildings; used to help direct runoff water away from the building. Drip Edge resembles nosing except that it has an outwardly angled bottom edge (preferably hemmed). To see the difference between Drip Edge and Nosing, See Nosing.
Dry Rot: Wood rot caused by certain fungi. Dry rot can result from condensation build-up, roof leaks that go untended, or from other problems. Dry rot will not remain localized. It can spread and damage any lumber touching the affected area.
Dual Level Drain: An item that will permit drainage at two different levels.
Dynamic Load: Any moving load on a roof such as people and equipment. Wind can also be considered a Dynamic Load.
Eave: A roof edge that extends out past the exterior wall line. (See Fig 1)
Eaves-Trough: Another name for Gutter.
Edge Stripping: Roofing material used to seal perimeter edge metal and the roof itself.
Edge Venting: The installation of vent material along a roof edge (e.g., Starter Vent) as part of a ventilation system. Edge vent material should be used in conjunction with other venting material (e.g., ridge vent), as it not intended for use by itself.
EER: Energy Efficiency Ratio; is worked out by dividing BTU hours by Watts
Elastomer: A material, which, after being stretched, will return to its original shape.
Elastomeric: Properties of a material that will permit it to return to its original shape after being stretched.
Elastomeric Coating: A coating that can be stretched to twice its dimensions and that will return to original when tension is released.
Elongation: The ability of a material to be stretched or lengthened.
Embedment: In roofing, to uniformly press one material into another, such as aggregate into bitumen, roofing felt into bitumen, or granules into a coating.
End Lap: The extension of one component of material past the end of an adjacent piece of material.
Envelope: 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 Bitumen-Stop.
EPDM: See Ethylene Propylene Diene Monomer.
Epichlorohydrin (ECH): A synthetic rubber material similar to EPDM with a stronger resistance to animal fats and oils than EPDM.
Epoxy: A type of synthetic, thermosetting resins that produce tough, hard, chemical-resistant coatings and adhesives.
Equipment Screen: A non-structural wall or screen constructed around rooftop equipment such as HVAC units, curbs, etc. to hide the look of the equipment and make the structure more aesthetically pleasing.
Ethylene Propylene Diene Monomer (EPDM): A thermoplastic rubber with high tear strength that can be cross-linked by both peroxides and sulphur.
Exhaust Vent: A device used to vent air from the roof cavity with vents that are installed on or near the higher portions of the roof such as the ridge.
Expansion Cleat: A cleat designed to handle thermal movement of the metal roof panels.
Expansion Coefficient: The amount that a specific material will vary in one dimension with a change of temperature.
Expansion Joint: A built-in separation between building sections to allow for free movement between the sections without damaging the buildings structural components.
Factory Seam: A splice/seam made in the roofing material by the manufacturer. It is preferable during installation to cut these splices out of the membrane.
Fading: Losing brightness or brilliance: dim
Fall: The amount of pitch a roof has
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: A general term covering a wide variety of screws and nails used to secure roof system components.
Felt: A roofing sheet made of interwoven fibres. The fibres can be wood or vegetable for Organic Felts, glass fibres for fibreglass felts, polyester, or asbestos.
Felt Machine: A machine that will install bitumen and felt at the same time.
Ferrule: A metal sleeve used as a spacer to keep gutter from being beat up when secured to fascia with spikes.
Fibreglass Insulation: Insulation composed of glass fibres used to insulate walls and roofs. It can be rigid board or blanket insulation.
Field of the Roof: Refers to the central part of a roof away from the perimeter.
Field Seam: A non-factory material seam made by joining overlapping seams together with adhesives, heat welders, or other means.
Filler: An inert ingredient added to roofing materials in order to alter their physical characteristics.
Fillet: A sealant material installed at horizontal and vertical planes to remove 90° angles.
Fin: A sharp protrusion in a roof deck that can damage roof components.
Flame Retardant: A substance used to impede a material’s tendency to burn or ignite.
Flammability: The ability of a material to burn or ignite.
Flange: A projection edge of a roof component such as flashings, skylight frames, pre-manufactured curbs, etc. Usually refers to the part that sits on the roof surface.
Flash:
v. To install flashing components.Flash Point: The lowest temperature of a liquid material at which combustion will occur when air reaches its surface.
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 Collar: A flashing component used to seal soil pipe vents, hot stacks or other roof penetrations.
Flat Lock: A type of interlocking two separate metal panels by folding one panel over on top itself and the folding the other down under itself and then hooking the panels together.
Fleece: Mats or felts used as a membrane backer and composed of fibres.
Flood Test: A water test performed to determine the effectiveness of a roof covering.
Flow: To become fluid in character.
Fluid-Applied Elastomer: A liquid elastomeric material that cures to form a continuous waterproofing membrane.
Foam Stop: The edge metal used to terminate Sprayed Polyurethane Foam.
Framed Opening: a structurally framed opening in a roof of a building for use in installing large items such as HVAC units, skylights, or ventilators.
Fully Adhered: A completely attached (adhered) roof membrane.
Gable: A triangular-shaped portion of the end wall of a building directly under the sloping roof and above the Eave line. See Fig 1.
Gable Roof: A roof configuration that has gable ends. See Fig 1.
Gable-On-Hip Roof: A roof configuration with hips coming up from the eave corners that terminate into a gable roof.
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.
Gambrel: A roof that has two different pitches.
Gauge: A standard of measurement. For instance the thickness of sheet metal or the diameter of wire. The thicker the wire or metal, the lower the gauge.
Girder: A main beam upon which floor joists rest, usually made of wood or steel.
Grain: A unit of measure for the mass of moisture: a unit of weight equal to 0.002285 ounces or 0.036 dram.
Granule: A small aggregate, naturally or synthetically coloured, used to surface cap sheets, shingles, and other granule-surfaced roof coverings.
Gravel: Aggregate consisting of rock fragments or pebbles.
Gravel Stop: A flanged, sheet metal edge flashing with an upward projection installed along the perimeter of a roof to stop the flow of bitumen over the edge.
Grout: A thin mortar used to fill cracks in masonry and tile.
Grout (Non-Shrink): A cementitious material used to partially fill penetration pockets (pitch pans). A pourable sealer is used afterward.
Gutter: A channel installed along the downslope perimeter of a roof to convey runoff water from the roof to the drain leaders or downpipes. (See Fig 1)
Gutter Clips: Plastic brackets used to support plastic gutters.
Gutter Strap: Metal bands used to support metal gutters.
Half Gable Roof: See Shed Roof.
Hand-Tabbing: Applying spots of adhesive to shingle tabs.
Hatch: A unit used to provide access to a roof from the interior of a building.
Heat Transfer: Thermal energy going from an area of higher temperature to an area of lower temperature by conduction, convection, or radiation.
Hem: The edge created by folding metal back on itself. Metal is hemmed for safety and strength reasons.
Hip: The angle formed by the intersection of two sloping roof planes. (See Fig 1)
Hip Roof: A roof that rises by inclined planes on all sides of a building. The line where two adjacent sloping sides of a roof meet is called the Hip.
Hoist: A mechanical lifting device. A hoist can be hand or electrically operated.
Holiday: An area where a liquid-applied material is missing.
Honeycomb: Small voids left in concrete because the mortar failed to fill the spaces around the aggregate.
Humidity: The amount of water vapour in the air.
HVAC: Acronym for Heating, Ventilating, and Air Conditioning.
Ice Dam: Ice formed at the transition from a warm surface to a cold surface, such as along the overhang of a house. The build-up of ice is the result of ice or snow melting on the roof area over the warmer, living area of a building and then refreezing when it runs down and reaches the overhang.
Ignition Temperature: The minimum temperature at which a material will combust.
Impact Resistance: A roof assembly’s ability to withstand the impact from falling objects such as hail.
Impregnate: To saturate; in roofing, asphalt impregnated fibreglass roofing felts are fibreglass mats that have been completely permeated with asphalt bitumen.
Incompatibility: Descriptive of two or more materials which are not suitable for use together.
Infiltration: The process by which air leaks into a building. In which case heat loss results. To find the infiltration heating load factor (HLF), the formula to account for the extra BTU's needed to heat the infiltrated air is:
BTU/HR = building volume x air changes x BTU/cu.ft/hr xTD (TD is temperature difference).
Infrared Thermography: The use of an infrared camera to detect moisture in roof insulation.
Inorganic: Involving neither organic life nor the products of organic life; relating to compounds not containing hydrocarbon groups.
Insect Screen: Material used to inhibit an insect’s ability to enter a building through openings in a roof such as vents.
Inside Drain: A drain positioned on a roof in a location other than at the perimeter. It drains surface water inside the building through closed pipes to a drainage system.
Insulation: Generally any material which slows down or retards the flow or transfer of heat. See also Thermal Insulation.
Intake Ventilation: The part of a ventilation system used to draw fresh air in. Usually vents installed in the soffit or along the eaves of a building.
Internal Pressure: Atmospheric pressure inside a structure that correlates to the number and location of openings and air leaks.
Inverted Roof Membrane Assembly (IRMA®): A variation of the "Protected Membrane Roof Assembly" in which Styrofoam® brand insulation is used. IRMA® and Styrofoam® are registered trademarks of the Dow Chemical Company.
Jack:
See Roof Jack.Joint Tape: Tape used to seal joints between insulation boards.
Joist: Any of the parallel horizontal beams set from wall to wall to support the boards of a floor, ceiling or roof of a building.
Kelvin: Thermometer scale on which a unit of measurement equals the Celsius degree but with zero being equal to minus 273 degrees Celcius
Knee Cap: Sheet metal trim that fits over a panel rib after it has been cut and bent.
Kynar Coating: Architectural coating that is UV stable and suitable for exterior use on aluminium and other metal surfaces.
Laitance: An accumulation of fine, powdery aggregate particles on fresh cement caused by the upward movement of water; indicates that too much water was used in the mix resulting in poor surface adhesion for a waterproofing layer.
Lap: The part of the roofing material that overlaps a section of adjacent material.
Lap Seam: Where two materials that overlap are sealed together.
Lead: A malleable metal once extensively used for flashing.
Leader Head: A component used to direct water from a through-wall scupper to a downpipe.
Leader Pipe: A conduit for carrying water from a gutter, scupper, drop outlet or other drainage unit from roof to ground level. Also known as Downpipe or Downspout. (See Fig 1)
Lift: The rise in Sprayed Polyurethane Foam resulting from a pass.
Liquid Applied Membrane: Generally applied in one or more coats to provide a fully-adhered waterproof membrane which conforms to all contours.
Live Loads: Temporary items on a roof such as equipment, people, snow, etc. which the roof must be designed to support.
Loose-Laid Roof Membranes: Roofing material attached only at the perimeter and at penetrations and held in place by ballast, pavers, or other materials.
M
Mansard: (1) A steep-sloped roof located at the perimeter of a building and usually used for decorative purposes. (2) The upper story formed by the lower slope of a mansard roof.
Mansard Roof: A steeper roof that terminates into a lower sloped roof at its high point.
Masonry: Refers to bricks, concrete, or concrete blocks.
Mastic: Heavy consistency compound that may remain adhesive and pliable with age. It is typically a waterproof compound applied to exterior walls and roof surfaces.
Mat: A thin layer of woven, non-woven, or knitted fibre used to reinforce a material.
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.
Mechanical Damage:
Damage to a roof by means of items puncturing or otherwise unnecessarily penetrating the roof system or any of its components. Screws or nails stuck in the roof and heel marks along base flashings are examples of mechanical damage.Mechanical Fasteners: Devices such as screws, plates, battens, nails, or other materials that are used to secure roofing materials.
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 are used to terminate the roofing membrane or material along roof edges. Metal flashings are also used in the field of the roof around penetrations.
Meter: Metric unit of length measurement equal to 39.37 inches.
Mil: A unit of measure equal to 0.001 inches (1/1000 in.) used to indicate the thickness of a roofing membrane.
Mildew: A superficial coating or discoloration of organic materials caused by fungi, especially under damp conditions.
Millimetre: Metric unit of measure equal to one thousandth (0.001) of a meter, or 0.03937 inches.
Mineral Fibre: Inorganic fibres of glass or rock.
Mineral-Surfaced Roofing: Roofing materials with a top surface consisting of mineral granules.
Mitre: The joint made by two diagonally cut pieces put together.
Moisture Relief Vent: A vent installed through the roofing membrane to relieve moisture vapour pressure that has been trapped within the roofing system.
Moisture Scan: A survey of a roof specifically to detect the amount of moisture present in the roof system. Devices used in moisture surveys can be capacitance meters, infrared cameras, and nuclear scanners. Infrared scans can be done from the air or on the surface of the roof. Capacitance and nuclear scans are done on the roof surface. It is argued that the most accurate scans are done from the surface of the roof with the most accurate of these being nuclear scans.
Mole Run: A term used to describe a ridge in a roof membrane that is not the result of improper deck or insulation joints.
Monitor: A large structure rising above the surrounding roof planes, designed to give light and/or ventilation to the interior of the building.
Monolithic: Used to describe something without seams; formed from a single material.
Monomer: A simple molecule that can combine with other to form a polymer.
Multiple Coats: More than one layer of coating applied to a substrate.
NAHB: National Association of Home Builders
Nailer: A piece of timber, preferably treated, that is secured to the deck, walls, or to premanufactured curbs. Nailers are used to receive fasteners for roof membranes. Generally, nailers are installed wherever it is necessary to secure base flashings and edge metal. Also see Blocking.
Newton (N): In the meter-kilogram-second system, the unit of force required to accelerate a mass of one kilogram one meter per second per second (s².)
Night Seal: To temporarily seal the edge of a roof membrane in order to protect it from moisture entry. A.K.A. Night Tie-Off and Water Cut-Off.
Noble: In reference to metal, inert or inactive.
Non-Breathing Membrane: A membrane that does not permit water vapour or air to permeate it.
Non-Flammable: Material with no measurable flash point.
Non-Friable: Refers to a material’s inability to be crushed or pulverized into a powder.
Non-Volatile Content: The portion of a material that will not evaporate.
Non-Vulcanised Material: A material that retains its thermoplastic properties throughout its service life.
Nonwoven: Random arrangement of the reinforcement fibres of a scrim sheet or mat.
Nosing:
Metal (or Fibreglass) flashing formed at a 90º angle and is installed around roof perimeters, curbs, platforms, etc. in order to protect the edge of the roofing system. Nosing should not be used in place of drip edge.Below is an example of the difference between drip edge and nosing. Though nosing is used commonly, the drip edge is better because it help keep run-off away from the fascia.
Open Valley: A valley where both sides of the roof are trimmed back from the centreline to expose the valley flashing material beneath.
Orange Peel Surface Texture: A surface with a texture comparable to the skin of an orange upon which a protective coating may be applied.
Organic: Formed from hydrocarbons.
OSB:
Oriented Strand Board - Often used as roof sheathing in place of plywood and predominantly used in the flat roof industry instead of plywood and chipboard.|
|
This is a photograph of what OSB (Oriented Strand Board) looks like. It is often used in place of plywood for roof sheathing.
Overlay: See Re-Cover.
Overspray: The loss of spray particles (from coatings, SPF, etc.) in the air.
Pallet: A platform used to hold materials.
Pan: (1) The concave piece of "Pan and Cover" tile whose rounded surface touches the top side of the roof substrate. (2) The flat part of a roofing panel located between the ribs.
Pan Flashing: A sheet metal flashing that covers an equipment platform and is designed to counter flash the base flashings surrounding the platform.
Parapet Wall: That part of a perimeter wall that extends above the surface of the roof.
Pass: The term used to describe the application of one layer of Spray Polyurethane Foam (SPF). The speed of a pass will determine foam thickness.
Pass Line: The distinct line formed between two passes of SPF. This line is the top skin of the bottom pass of the SPF.
Peggies: Slates 10-14in (254-356mm)in length.
Penetration: Any object that pierces the surface of the roof.
Percent Elongation: The maximum amount that a material can be lengthened or stretched before breaking; expressed as a percentage of the original length of material tested.
Perlite: A natural volcanic glass having distinctive concentric cracks and a relatively high water content. Perlite in a fluffy heat expanded form is used in lightweight insulating concrete, fire-resistant rigid insulation board (R = 2.78 per inch) and potting soil.
Perm:
A unit of water vapour transmission, defined as one grain of water vapour per square foot per hour per inch of mercury (Hg) pressure difference (1 inch of mercury = 0.491 psi).Permeability: The rate of flow of a liquid or gas through a porous material.
PH: A measure of the acidity or alkalinity of a solution, numerically equal to 7 for neutral solutions, increasing with increasing alkalinity and decreasing with increasing acidity. The pH scale commonly in use ranges from 0 to 14.
Phasing: Installing roof system components in separate time intervals. For instance, installing a base sheet, and then two plies of roofing one day, and coming back and installing the remaining two plies one or more days later. It is generally not considered Phasing if the surfacing is applied at a later date.
Pinhole: A small hole in a coating, foil, membrane, or other roofing material.
Pipe Boot: A prefabricated flashing piece used to flash around circular pipe penetrations. Also known as a Roof Jack.
Pitch: Term used to describe Roof Slope and also short for Coal Tar Pitch.
Pitch Pocket (A.K.A. Pitch Pan): A flanged piece of flashing material placed around irregularly shaped roof penetrations and filled with grout and a pourable sealer to seal around the penetration in order to seal it from against moisture entry. Pitch pockets are a good source of leaks and should be avoided if possible. For an example on how to properly fill a pitch pocket,
Plywood: Wooden panels formed by gluing thin sheets of wood together, with the grain of adjacent layers arranged at right angles.
Polymer: Any of numerous natural and synthetic compounds of usually high molecular weight consisting of up to millions of repeated linked units, each a relatively light and simple molecule.
Polyvinyl Chloride (PVC): A thermoplastic polymer that can be compounded into flexible and rigid forms through the use of plasticizers, stabilizers, fillers, and other modifiers; rigid forms are used in pipes; flexible forms are used in the manufacture of sheeting and roof membrane materials.
Ponding: The accumulation of water at low-lying areas on a roof.
Pop Rivet: A small metal pin having a head on one end, inserted through aligned holes in pieces of light gauge metal to be joined and then the head is expanded to join the metal.
Popcorn Surface Texture: A coarse surface texture of SPF considered unacceptable for coatings.
Positive Drainage: The drainage condition of a roof where all water is gone from the roof surface within forty-eight hours of precipitation during normal drying conditions.
Pot Life: The period of time during which a material with multiple ingredients can be applied or administered after being mixed together.
Pourable Sealer: A type of sealant that is initially in liquid form commonly used in conjunction with pitch pans to form a watertight barrier around penetrations that are difficult to flash.
Primer: A material that is applied to a surface in order to increase that surface’s ability to adhere to or work in conjunction with a subsequently applied material.
Proportioner: A pumping unit comprised of two (2) positive displacement pumps that is designed to dispense two (2) components at a precise ratio. Used in SPF and plural component coating applications.
Puncture Resistance: The ability of a material to withstand being pierced by a sharp object.
Purlin: Horizontal secondary structural member used to transfer loads from the primary structural members.
PVC: Polyvinyl Chloride.
R-Value: The measure of a material’s resistance to heat flow. The higher a material’s R-value, the more it insulates. For more information on R-Value, See Table 1
Racking: The method of installing asphalt shingles where the shingles are installed straight up to the ridge rather than horizontally. If this method is used with 3-tab shingles, the throats of every other course will line up.
Rafter: The structural member extending from the downslope perimeter of a roof to the ridge or hip and is designed to support the roof deck and roof system components.
Raggle: A groove that is cut into the side of a vertical surface such as a wall or chimney that is used to insert a flashing element such as a reglet or counterflashing.
|
The red arrow in the following image shows a Raggle. The greyish pieces that you see are pieces of lead being used to hold the flashings in place until they can be properly mortared.
|
|
|
Rake: The sloped perimeter edge of a roof that runs from the eaves to the ridge. The rake is usually perpendicular to the eaves and ridge. (See Fig 1)
Rake-Starter: A starter strip placed along rake edges for use in asphalt shingle roofing. See also Bleeder Strip.
Re-Cover (Overlay): The installation of a new roof system over an existing system without removing an existing system
Reinforced Membrane: A roofing membrane that has been strengthened by adding polyester scrims or mats, glass fibres or other material.
Relative Humidity: The amount of water vapour in the air compared to the amount of water vapour that the air can hold at a given temperature. For example, if the relative humidity is 50 percent, then the amount of water vapour in the air is half of what the air could actually hold at that temperature.
Reroofing: The procedure of installing a new roof system.
Ridge: The line where two planes of roof intersect, forming the highest point on the roof that runs the entire length of the roof. (See Fig 1)
Ridge Cap: Material applied over the ridge or hip of a roof.
Ridge Course: The final course of roofing applied that covers the area where two or more roof planes intersect.
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.
Ridging: The formation of a Buckle.
Roll Goods: The term used for all roofing materials that come in rolls.
Roof Assembly: A term used to describe all of the roof components including structural roof deck.
Roof Curb: A frame used to structurally mount rooftop equipment such as HVAC units, exhaust fans, skylight, etc.; may be pre-constructed or constructed on site.
Roofer: An individual who installs roof systems and materials.
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 Overhang: That portion of the roof that extends beyond the exterior wall line of the building.
Roof Seamer: (1) A mechanical device used to crimp metal roof panels and make the seams watertight. (2) A machine used to weld membrane laps of PVC (Thermoplastic) roofing material.
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. For more information on Roof Slope, See Fig 2
Roof System: Multiple roof components assembled to provide waterproofing (and sometimes insulating) capabilities for a structure.
Run: The horizontal dimension of a slope. See Fig 2.
Rust Blush: Early stage of rust indicated by an orange or reddish colour.
Saddle: (1) A type of flashing usually used in conjunction with step, counter, and apron flashings on steep slope roof systems. (2) A small, somewhat pyramid-shaped figure constructed in between sump drains that is used to direct run-off water toward the sump drains.
Sag: Settling or drooping of base flashings that have not been properly secured to a surface or boards due to moisture exposure.
Scrim: Woven or nonwoven material used to reinforce membranes; it is usually laminated or coated to produce the membrane.
Scuttle: A unit that provides access to the roof from the interior of the building. See also Hatch.
Sealant: Generic term for a multitude of materials used to seal joints or junctures against moisture or weather.
Sealer: Coating designed to prevent bleed-out or bleed-through.
Self Levelling: A term used to describe a viscous material that is applied by pouring, in its uncured state, it spreads out evenly.
Selvage: The unsurfaced strip along a sheet of roll roofing which forms the under portion at the lap in the application of the roof covering.
Shed Roof: A roof having only one slope or pitch, with only one set of rafters which fall from higher to lower wall.
Shingles: Small units of material which are laid in a series of overlapping rows as a covering on pitched roofs.
Silicone Sealant: A sealant having as its chemical compound a backbone consisting of alternate silicone-oxygen atoms.
Skew: Method of putting in nails in at a slight angle, one opposing the next so as to greatly decrease the chance of the boards lifting.
Skylight: A structure on the roof that is designed to admit light and is somewhat above the plane of the roof surface.
Slate: A dark grey stratified stone cut relatively thin and installed on pitch roofs in a series of overlapping rows.
Slope: Incline or pitch of roof surface.
Soffit: The underside of a part or member of a building extending out from the plane of the buildings walls.
Span: The horizontal distance between supporting structures such as beams, trusses, or columns.
Specification: Detailed written instructions which, when clear and concise, explain each phase of work to be done.
Stack: The vertical pipe of a system of soil, waste or vent piping.
String Line: A nylon line usually strung tightly between two supports to indicate direction and elevation.
Substrate: A part or substance which lies below and supports another.
Tab: The portion of an asphalt shingle that is outlined by the cutouts.
Tapered Edge Strip: Tapered insulation strip used to ease transitions from one substrate elevation to another and to provide slope along roof perimeters.
Tape: See Joint Tape and Splice Tape.
Tar: A brown or black bituminous material, liquid or semi-solid in consistency, in which the predominating constituents are bitumens obtained as condensates in the processing of coal, petroleum, oil-shale, wood, or other organic materials.
Tar Boil: A small bubble found in the flood coat of an aggregate-surfaced built-up roof; usually the result of trapped moisture vapour. Tar Boils