Commercial Roofing Glossary

From novice to expert, your guide to commercial roofing terms.

A Handy Commercial Roof Decoder Ring

Trying to grasp the terminology used in commercial roofing can sometimes feel like learning a new language. From roof framing terminology to the intricate details of roof structure terminology, there’s a lot to grasp. Our glossary aims to simplify this process, providing clarity on common roofing terms and essential roof terminology.

Whether you’re a novice looking to understand basic roof terms or a professional seeking deeper insights into roof construction terminology, we’ve got you covered. By having an improved understanding of roofing terminology, you’ll become better equipped to discuss and understand all things related to commercial roofing.

Commercial Roofing Glossary


The ability of a material to accept and retain a liquid, often related to the capacity of insulation or roofing to retain water.


The bonding power of a material. In roofing, dry surfaces can bond by applying pressure.


Crushed stone, gravel, or other granular materials that protect and weigh down a roof surface or provide a finished surface.

Apron Flashing:

A term used for a flashing located at the juncture of the top of the sloped roof and a vertical wall or steeper-sloped roof.


A sticky, black, and highly viscous liquid or semi-solid form of petroleum, often used in waterproofing products and roofing shingles.


A material, often stones, used to weigh down and stabilize roofing components.


A black viscous mixture of hydrocarbons used in roofing and asphalt.


A raised area on the roof, often filled with air or water, indicating separation beneath the surface.

Built-Up Roof (BUR):

A type of roofing made up of alternating layers of tar and reinforcing fabric.

Cant Strip:

A beveled or triangular-shaped piece of wood, metal, or foam used to ease the transition from a horizontal roof deck to a vertical surface.

Cap Sheet:

The top layer in specific roofing systems, typically granulated and UV resistant.


A liquid-applied substance used to protect and seal roofing materials.


A peaked construction used to divert water around obstructions on the roof.


The structural substrate, usually made of wood or metal, over which roofing materials are applied.


A small structure with a window that projects from a sloped roof.


A pipe that carries rainwater from a roof to a drain or ground level.

Drip Edge:

An edging device installed along the outermost perimeter of the roof to direct water runoff.


The overhanging lower edge of a roof.


Ethylene propylene diene monomer, a type of synthetic rubber roofing membrane.

Expansion Joint:

A device used to allow for the expansion and contraction of different construction materials.


The vertical board around the edge of a roof.


General term for nails, staples, screws, or bolts used to secure roofing material.


Materials used to prevent water infiltration when the roof intersects with another surface.


The triangular section of the outer wall at the edge of a pitched roof.

Galvanized Steel:

Steel coated with a layer of zinc for corrosion resistance.


Small, gravel-like particles that coat the top of shingles, providing UV protection and color.


A channel that collects and diverts rainwater shed by the roof.


The external angle formed by the intersection of two sloping roof planes.


Materials that reduce heat transfer into or out of a building.


Horizontal beams that support the roofing system.


The part of the roofing material that overlaps a section of adjacent material.


A type of roof with four sloping sides, each of which becomes steeper halfway down.


A flexible or rigid material, either pre-formed or formed in place, used to waterproof roofs.

Modified Bitumen:

A roofing material made from asphalt reinforced with fiberglass or polyester.


A wood or metal securement on top of or to the side of the roof deck that provides a receiving medium for the fasteners.


A wall-like structure at the edge of a roof.


Any object, such as a pipe or stack, which passes through the roof.


The angle or slope of a roof.


A layer of roofing material; multiple layers form a built-up roof system.


Polyvinyl Chloride, a type of single-ply roofing system.


The framing beams supporting the roof deck, running from the ridge to the eaves.


The top edge where two sloping sides of a roof meet.


An opening in a wall or parapet for the drainage of water from a roof.


The joint or connection between two adjacent sections of roofing material.

Single-Ply Roofing:

A roofing system with a single material layer as the primary and topmost watertight surface.


The exposed surface beneath the overhanging portion of a roof eave.


Thermoplastic Olefin, a type of single-ply roofing material.


A layer of material placed between the roof deck and the roofing material, often for waterproofing.


The angle formed at the intersection of two sloping roof surfaces.

Vapor Retarder:

A material designed to resist the migration of water vapor.


An opening or device that permits air or vapor to exit the roofing system.


The process or treatment of making a structure resistant to water infiltration.


The natural deterioration of materials due to environmental factors.

Weep Hole:

A small opening that allows for drainage of water.

Wind Uplift:

The force exerted by wind below roofing components, potentially lifting them off the structure.

Join Our Email Newsletter…

for the latest roofing trends and tips so you can enjoy the rain again!