AGGREGATE – In roofing, crushed stone, curshed slag or water-worn gravel used for surfacing for roof coverings.
BALLAST – In roofing, ballast comes in the form of large stones or paver systems or lightoweight interlocking paver systems and is sused to prvide uplift resistance for roofing systems that are not adhered or mechanically attached to the roof deck.
BUILDING INTEGRATED PHOTOVOLTAIC ROOFING – A roofing product consisting of electricity generating photovoltaic component integrated into a roof covering.
BUILT-UP ROOF COVERING – Two or more layers of felt cemented together and surfaced with a cap sheet, mineral aggregate, smooth coating or similar surfacing material.
FLASHING – The roofing component used to seal roofing systems where the system is interrupted or terminated.
INTERLAYMENT – A layer of felt or nonbituminous saturated felt not less than 18 inches (457 mm) wide, shingled between each course of a wood-shake roof covering.
MECHANICAL EQUIPMENT SCREEN – A partially enclosed rooftop structure used to aesthetically conceal heating, ventiliating and air conditioning (HVAC) electircal or mechanical equipment from view.
METAL ROOF PANEL – An interlocking metal sheet having a minimum installed weather exposure of 3 square feet (0.279 m2) per sheet.
METAL ROOF SHINGLE – An interlocking metal sheet having an installed weather exposure less than 3 square feet per (0.279 m^2) sheet.
MODIFIED BITUMEN ROOF COVERING – One or more layers of polymer-modified asphalt sheets. The sheet materials shall be fully adhered or mechanically attached to the substrate or held in place with an approved ballast layer.
PENTHOUSE – An enclosed, unoccupied structure above the roof of a building, other than a tank, tower, spire, dome bupola or bulkhead.
PHOTOVOLTAIC MODULE – A complete, environmentally protected unit consisting of solar cells, optics and other components, exclusive or tracker, designed to generate DC power when exposed to sunlight.
PHOTOVOLTAIC PANEL – A collection of modules mechanically fasthened together, wired and designed to provide a field-installable unit.
PHOTOVOLTAIC PANEL SYSTEM – A system that incorporates discrete photovoltaic panels, that converts solarradiation into electricity, including rack support systems.
POSITIVE ROOF DRAINAGE – The drainage condition in which consideration has been made for all loading deflections of the roof deck, and additional slope has been provided to ensure drainage of the roof within 48 hours of precipitation.
RADIANT BARRIER – A material having a low-emittance surface of 0.1 or less installed in building assemblies.
REROOFING – The process of recovering or replacing an existing roof covering.
ROOF ASSEMBLY – A system designed to provide weather protection and resistance to design loads. The sytem consists of a roof covering and roof deck or a single component serving as both the roof covering and the roof deck. A roof assembly includes the roof deck vapo retarder, substrate or thermal barrier, insulation and roof covering.
ROOF COVERING – The covering applied to the roof deck for weather resistance, fire classification or appearance.
ROOF COVERING SYSTEM – See “roof assembly”
ROOF DECK – The flat or sloped surface not including its supporting members or vertical supports.
ROOF RECOVER – The process of installing an additional roof covering over a prepared existing roof covering without removing the existing roof covering.
ROOF REPAIR – Reconstruction or renewal of any part of an existing roof for the purpose of its maintenance.
ROOF REPLACEMENT – The process of removing the existing roof covering, repairing any damaged substrate and installing a new roof covering.
ROOF SECTION – A separation of division of a roof area by existing joints, parapet walls, flashing (excluding valleys), difference of elecvation (excluding hips and ridges), roof type or legal description; not including the roof area required for a proper tie-off with an existing system.
ROOF VENTILATION – The natural or mechanical process of supplying conditioned or unconditioned air to, or removing such air from, attics, cathedral ceilings or other enclised spaces over which a roof assembly is installed.
ROOFTOP STRUCTURE – An enclosed structure on or above the roof of any part of a building.
SCUPPER – An opening in a wall or parapet that allows water to drain from a roof.
SINGLE-PLY MEMBRANE – A roofing membrane that is field applied using one layer of membrane material (either homogeneous or composite) rather than multiple layers.
UNDERLAYMENT – One or more layers of felt, sheathing, paper, nonbituminous saturated felt or other approved material over which a steep-slope roof covering is applied.
VEGETATION ROOF – As assembly of interacting components designed to waterproof and normally insulate a building’s top surface that includes, by design, vegetation and related landscape elements.