A Glossary of Commercial Roofing

Need to study up on your roofing terms? Jump right in with our glossary below! If you can’t find your desired term in the Commercial Roofing Glossary below.

Commercial Roofing Terms (A-Z)

Acrylic Coating: a water based restorative coating designed to increase reflectivity and reduce the effects of rusting.

Aggregate: gravel material often seen on the top of built up roofing (BUR). Often intentionally worn down by water prior to use.

Algae: a common hazard to roofing color and durability. This fungus often grows on roofs in areas with frequent rain and high humidity, and must be removed in a timely manner to avoid damage.

Aluminum Roofing: a popular form of metal roofing, known for its premium rust-resistance and high reflectivity. Typically installed in corrugated or standing seam panels.

ASTM: stands for American Society for Testing of Materials. An associate dedicated to creating material testing methods and durability standards. Often referred to when researching material impact and fire resistance.

Blistering: unsightly bubbling sometimes produced when moisture gets trapped beneath the surface of a roofing system.

Boot: a type of flexible flashing used to cover the gaps surrounding a rooftop penetration, such as a pipe or vent.

Building Code: national, state, or municipal construction standards that govern new construction and building maintenance.

Built-up Roofing (BUR): a form of asphalt roofing historically known for its impact resistance. Typically utilizes a multi-layer system of felt, tar, and gravel/stone.

Butyl Tape: used to seal the gaps between roofing material seams and prevent water infiltration.

Carpet Roll: prevents material wrinkling during installations, especially in cold weather climates.

Caulking: a sealing process / material used to block water, air, and pests from entering vulnerable areas of a roofing system. Commonly used at joints, junctures, and seams.

Chemical Resistance: describes a material’s ability to withstand exposure to certain chemicals without being damaged.

Class A Fire Resistance: the highest rating for fire resistance as set by the ASTM. Materials with this rating are made to endure harsh fire exposure from outside the structure.

Cool Roofing: any roofing system designed to reduce heat gain during daylight hours. Most cool roofing systems utilize a reflective surface to limit the amount of sunlight absorbed. As a result, the underlying buildings experience significant improvements in building efficiency.

Corrugated Metal Roofing: a common form of paneled metal roofing. Usually composed of aluminum or steel, these metal sheets are attached to the rooftop via rust-resistant fasteners. Corrugated panels vary by gauge (thickness), ridge/wave style, and color.

Counterflashing: prevents water from clinging to the rooftop walls and directs it down to the surface for safe draining. May by mounted in the wall itself, adhered to the side, or a combination of the two.

Coping Cap: the metal, stone, masonry, or other material that covers the top of a parapet wall.

Core Cuts: a process of testing the health and moisture conditions of an existing roofing systems, by extracting a series of deep cuts that reach all the way down to the decking.

Dead Load: the weight of a roofing system, including all attached fixtures, which the system itself must be able to sustain.

Decking: a flat surface in a roofing structure designed to support and provide points of attachment for the underlayment and rooftop materials. Located above structural trusses and joists.

Dielectric Welding: also known as high-frequency welding or radio frequency welding. Used to bind thermoplastic materials together, especially at the joints.

Dome Strainer: prevents debris from entering a drain boot. Typically made from aluminum for premium rust resistance.

Drain: a collection point for water that safely diverts rain and other fluids away from the rooftop.

Edge Details: detailing on the ends of roofing edges used to block water infiltration.

Elastomeric Roofing: seamless, restorative coating solutions designed for thermal flexibility. Protects the underlying roofing structure from leaks, weathering hazards, and other threats.

Emergency Roof Repair: professional relief service provided outside of standard business hours or on the weekend. Sometimes used to describe a situation that demands immediate repairs to avoid further damage and expense.

Emissivity: a term describing how well a roofing surface releases pent up thermal energy (primarily produced by sunlight).

EPDM Roofing: stands for ethylene propylene diene monomer; more often referred to as “rubber roofing”. A cheaper, rubberized form of single ply roofing made to withstand the harsh impact of hail, while also expanding and contracting as needed with seasonal temperature change. Typically comes in black.

Expansion Joint: allows for the natural thermal expansion and contraction of roofing materials caused by ambient temperature changes. An important consideration during installation.

Fascia: the extreme edge of a sloped roofing system. Durable boards (typically composed of wood, metal, or vinyl) cover the gap between roofing and the underlying soffit, preventing moisture and pest infiltration.

Fastener: used to attach metal roofing panels to the surface of a rooftop. Typically made of rust-resistant material, these may require retightening every ten years or so.

Flashing: metal or other material installed between a vertical and horizontal surface for the purpose of blocking rain water and debris.

Flat Roof Coatings: restorative coatings specifically designed to overcome the common hazards of flat roofs, especially water ponding. Often used to create a seamless top over the existing roof ply, reducing the potential for leaks.

Flat Roofing: the most common category of commercial roofing, typically utilizing a single ply material. Flat roofs have very light gradients, allowing water runoff but leaving plenty of space for rooftop equipment.

Green Roofing: roofing solutions that utilize a top layer of plant life to protect the underlying structure, reduce water runoff, greatly limit heat gain, and purify the surrounding air. The flora is supported by several layers below, including a special growing medium and root barrier. The term may also be used to describe roofing solutions that promote energy efficiency and reduce waste.

Gutter: troughing installed beneath the termination of a roof to catch draining rain water and divert it safely away from the structure. Often made from metal or vinyl.

Hot Pipe: a type of roof penetration marked by its round shape and hot temperature (≥110°F).

Ice Dams: ice buildup that traps snow and water on top of a roofing structure. The added weight causes significant strain on the underlying roofing system, and the ice poses a threat to any property below should it suddenly fall off.

Impact Resistance: the ability of a roof or rooftop substance to resist the force of a falling object. Usually used to describe a system’s resilience against hail damage and falling debris.

Industrial Roof Coating: restorative coatings specifically designed to overcome the chemical, thermal, and mechanical threats unique to industrial buildings.

Industrial Roofing: roofing solutions, processes, and challenges associated with manufacturing businesses. May sometimes be used to describe any expansive roofing system.

Infrared Moisture / Leak Detection: an inspection process involving special cameras that detect the differences in heat created by moisture infiltration and converts them into a thermal image.

Inspections: the process of closely examining a roofing structure for the purpose of assessing its current health, exposing damage, and establishing maintenance requirements. Typically involves an eyeball inspection by a roofing professional, but may also include additional imaging equipment.

Insurance Claims Help: professional roof inspection and reporting designed to provide supplementary evidence during a roof damage insurance claim. May be used in addition to or in lieu of an adjuster’s inspection, depending on the associated insurance agency’s policy.

Leak Detection: an inspection process specifically designed to locate and expose damaged roofing segments vulnerable to water infiltration. May involve a close analysis with the human eye and/or imaging equipment.

LEED Certification: stands for Leadership in Energy and Environmental Design. Used by the United States Green Building Council used to identify buildings that meet its standards for environmental performance and efficiency.

Mechanical Damage: rooftop degradation caused by physical trauma, such as punctures, penetrations, or tearing. Often used to describe damage caused by foot traffic or moving equipment across a roofing system.

Mechanical Lock Metal Roof: a variety of standing seam metal roofing used for steeper slope rooftops. Seam locks in this variety must be formed by hand during installation.

Membrane: a roofing solution designed to block water infiltration and protect against other elemental threats. Typically comes in large rolls for easy transportation and installation. See single ply roofing.

Metal Anchors: special rust-resistant bolts used to attach a new roofing system to the underlying structure.

Metal Retrofit: the process of covering a metal roof with a new membrane to address severe corrosion, leaks, and/or condensation problems.

Metal Roof Coating: the process of coating a metal system for the purpose of color restoration, UV radiation resistance, rust prevention, and/or greater sunlight reflection.

Metal Roofing: a type of roof usually composed of coated steel or aluminum, providing strong weather protection and energy-efficiency. May be installed in shingle form, but typically comes in sheets attached by metal fasteners.

Modified Bitumen Roofing: a type of roofing made of altered asphalt material. Known for its flexible nature and puncture-resistant surfacing.

Monolithic: composed of or created from one material. Often used to describe restorative roof coating solutions.

NRCA: National Roofing Contractors Association. Popular association for roofing professionals around the United States, offering certifications and helpful resources on the industry.

Overdriven: when a screw is pushed too deep into a roofing surface, potentially creating a leaking hazard.

Parapet Wall Flashing: a type of flashing specifically made to cover the roof walls.

Pitch Pocket: a type of flashing installed around a roofing penetration to block water and debris. Typically involves a metal or membranous flashing, plus poured sealant.

Polyurea Roof Coating: a type of protective roof coating known for its mechanical and chemical resistance. Also popular for its powerful protection against standing water.

Positive Drainage: describes a roofing slope with an adequate gradient for proper water drainage.

Pull Test: a test that involves applying mechanical force to a membrane, fastener, or another roofing component to gauge how much force is required to remove that component.

PVC Roofing: stands for polyvinyl chloride. A premium plastic, single ply solution designed for impressive chemical, fire, weather, and mechanical resistance. Typically comes in a reflective white color for enhanced energy-efficiency.

Reflectivity: measures the percentage of sunlight (and resulting heat) reflected by a roofing surface. Greatly determines the energy-efficiency of a roofing system.

Roof Consultant: any roofing professional tasked with providing advice about a particular roofing project, system, or challenge. Typically an individual with years of roofing industry experience, especially in the field related to the associated client.

Roof Replacement: the process of removing a damaged and/or degraded roofing system (typically down to the decking), then installing a replacement roof.

Roof Restoration: an alternative to basic repair and full replacement. Involves minor structural repairs, followed by a protective coating. May be used to extend the life of an existing roof, or enhance a new installation.

Rubber Roof Coating: often referred to as liquid rubber. A liquid EPDM coating designed to withstand thermal expansion without needing seams. Often combined with a white finish for better reflectivity.

Rubber Roofing: single ply roofing designed for higher seasonal flexibility and impact resistance. Sometimes used to refer to EPDM or TPO membranes.

Scupper: a draining installation within a parapet or uplifted roof edge.

Sealant: used to waterproof seams or cracks in a roofing system. May refer to caulking and other similar materials.

Separator: when contact between two different materials would cause corrosion or another form of degradation, this device creates a barrier between them.

Skylight: a specialized window mounted in a ceiling/rooftop. Designed to admit additional natural light into the structure.

Single Ply Roofing: a common form of flat roofing. Utilizes a single membrane (or ply) to cover the rooftop, typically installed in sheets using adhesive, anchors, or ballasts.

Silicone Roof Coating: sometimes known as silicone roofing. A commercial roof restoration material that creates a seamless, waterproof top layer.

Slipsheet: a special sheet that prevents a roofing component or material from coming into contact with a non-compatible component or material, preventing chemical or corrosive degradation. See separator.

Snap Lock Metal Roof: a form of standing seam roofing used on gentle-slope systems. Panels come prefabricated to snap into place during installation.

Soffit: the vented underside of sloped roofing sections that protrude beyond the outer wall. Allows heat to exit attic spaces during peak sunlight hours, reducing energy costs.

Solar Reflectance Index (SRI): used to rate roofing system efficiency by gauging reflectance and emittance.

SPF Spray Foam Roofing: stands for spray polyurethane foam, a cool roofing solution designed to be sprayed into place, hardening over a short period of time. Once the foam solidifies, the result is a seamless and energy-efficient system.

Standing Seam Metal Roof: a premium style of metal roofing. Panels overlap in vertical seams, strengthening the overall structure and blocking rain from the underlying layers. Standing seam panels are usually thicker than simple corrugated panels.

Steel Roofing: one of the most popular forms of metal roofing. Steel roofs typically utilize a form of coated steel sheets that produce a strong weather barrier, though they may also come in shingle form.

Substrate: describes any layer located beneath the exposed rooftop. Decking, recovered membranes or paneling, or even rigid insulation may be described as a substrate.

Tear-off: the process of removing components or the entirety of a roofing system. Complete tear-offs usually involve stripping the roof down to the decking.

Thermal Imaging Service: a form of leak detection and energy-efficiency audit. It detects and indicates differences in temperature between sections of a rooftop.

Thermoplastic Membrane: a membrane (or ply) molded by the use of extreme heat. Membranes of this variety typically have much stronger seams. Material examples include TPO and PVC.

Tie-In: a seal or border dividing two separate membranes. May be used to separate old and new membrane sections, and/or two different materials.

TPO Roofing: stands for thermoplastic polyolefin. A form of single ply, rubberized roofing that typically comes in a reflective white color.

Two-way Air Vent: designed to allow limited air flow through a roofing system, lessening the negative effects of negative air flow.

Ultraviolet (UV) Radiation: a degrading force produced by sunlight. Over time, it naturally causes colors to fade and roofing materials to crack over time.

Underlayment: a sheet placed over the surface of roof decking prior to installing the subsequent layers. Protects some protection against moisture infiltration.

Urethane Modified Acrylic Coating: a form of reflective roof coating designed for stronger resistance against water erosion.

Vents/Pipe Stacks: types of rooftop penetrations, identifiable by their round shape.

Vulcanized Rubber Roofing: specialized rubber material designed for stronger internal cohesion and external chemical resistance. Provides stronger protection against corrosion and water pooling than non-treated rubber.

Wind Load: the force placed on a building or roof as wind strikes it.

Wind Uplift: the force inflicted on a roofing system when upward pressure (created by wind) is greater than downward pressure. Measured in pounds per square foot.

Have Questions?

Be sure to check out our helpful guides from Roofer’s Guild in the links below.

Related Links:
3 Ways to Take Advantage During Your Next Roof Inspection 
How to Choose Your Commercial Metal Roofing (in 3 Steps) 
Roof Coatings