Commercial Roofing Glossary

A–C

Asphalt Shingles

Common residential roofing material made from fiberglass and asphalt, known for affordability and ease of installation.

Ballast

Loose stone or gravel placed on top of a roof membrane to hold it in place, protect it from UV exposure, and provide weight against wind uplift.

Base Sheet

The first layer of a built-up or modified bitumen roofing system installed over insulation or deck to provide a smooth, stable surface for subsequent layers.

Built-Up Roofing (BUR)

A traditional commercial system made by alternating layers of bitumen (asphalt or coal tar) and reinforcing fabrics (plies), topped with gravel or a reflective coating.

Cap Sheet

The top layer of a modified bitumen or built-up roof system, often with granules or reflective surfacing.

Cant Strip

An angled strip used where the roof deck meets vertical walls or curbs to create a smooth transition, improving membrane adhesion and reducing stress.

Commercial Roof Coating

Liquid-applied membranes used to extend roof life and improve energy efficiency. Common types include acrylic, silicone, polyurethane, elastomeric, and asphalt-based coatings.

Commercial Roof Maintenance

Ongoing inspections, repairs, and preventative care to extend the life of a commercial roof system.

Commercial Roof Repair

Fixing leaks, damage, or wear on commercial roofing systems to restore functionality.

Commercial Roof Replacement

Removing and installing a new commercial roof when the existing system is beyond repair or expired.

Commercial Roof Restoration

The process of repairing and recoating an existing roof system to extend its life, improve waterproofing, and enhance energy efficiency without full replacement.

Cool Roof

A reflective roofing system designed to reflect more sunlight and absorb less heat, lowering building cooling costs.

Corrugated Metal

Corrugated metal is a type of commercial roofing panel with repetitive ridges and grooves that add strength, improve drainage, and offer a cost-effective, lightweight roofing solution.

Cover Board

A rigid board installed between the insulation and membrane to improve durability and fire resistance.

Crickets (or Saddles)

Small peaked structures built into flat roof systems to divert water toward drains and away from HVAC curbs or skylights.

D–F

Elastomeric barrier

A flexible, waterproof coating typically used in construction to seal and protect surfaces such as roofs, walls, or foundations. It’s made from elastomeric polymers, which allow it to stretch and return to its original shape without cracking.

EPDM

A durable synthetic rubber roofing membrane used in low-slope commercial buildings. Known for its flexibility, weather resistance, and long service life.

Flat Roofs

Low-slope roofing systems commonly used in commercial settings. These roofs often require specialized materials and drainage solutions to prevent water buildup.

G–I

(No terms in this section yet)

J–L

Low-Sloped Roof 

M–O

Mechanically Attached

A membrane attachment method using screws and plates to fasten the roof system to the deck.

Metal Edge

A flashing component installed at roof perimeters to protect the membrane and provide a clean finish.

Metal Roofing Systems

Roofing systems made from metal panels or shingles that provide durable, long-lasting protection and resistance to weather elements.

Modified Bitumen

A rolled asphalt-based membrane reinforced with polyester or fiberglass, often installed using heat, adhesives, or cold-applied methods.

NDL (No Dollar Limit) Warranty

A commercial roofing warranty that covers the full cost of repair or replacement, regardless of cost, if the system fails within the coverage terms.

Overburden

Any material or structure (e.g., solar panels, pavers, rooftop gardens) installed on top of a roofing system.

P–R

Penetration

Any object that passes through the roof deck or membrane, such as vents, pipes, or skylights, requiring flashing to prevent leaks.

Polyurethane Coating

A durable liquid-applied roof coating known for high tensile strength, flexibility, and chemical resistance.

PVC Roofs

Single-ply roofing systems made from polyvinyl chloride offer excellent chemical resistance, weldable seams, and reflectivity for commercial flat roofs.

S–U

Scupper

An outlet in the side of a building’s parapet wall that allows rainwater to drain from a flat roof.

Silicone Coating

A UV-stable and waterproof liquid coating used to restore and protect flat roofs, especially in ponding areas.

Solar Reflectance

Solar reflectance is the ability of a roofing material to reflect sunlight, including visible, infrared, and ultraviolet wavelengths. Materials with high solar reflectance absorb less heat, helping to keep buildings cooler and reduce energy costs, especially in sunny or hot climates.

SPF (Spray Polyurethane Foam)

A closed-cell foam sprayed onto roofs that expands and hardens, creating a seamless, insulating waterproof layer.

Standing Seam Metal Roofing

A type of metal roofing system where long, vertical panels are joined together by raised seams that run continuously from the roof ridge to the eaves. The seams are typically 1 to 2 inches high and are either mechanically crimped or snapped together, concealing the fasteners and providing a sleek, weather-tight finish ideal for both commercial and residential applications.

TPO 

A thermoplastic polyolefin-based coating applied to restore aged TPO membranes, improving reflectivity and waterproofing.

Urethane Coating

A tough, flexible liquid-applied coating known for excellent chemical and abrasion resistance, commonly used in commercial roof restoration.

V–Z

Vapor Barrier

A layer installed to prevent moisture from passing from the interior of a building into the roofing system.

Walk Pads

Protective mats installed on commercial roofs to provide safe access for maintenance and prevent membrane damage from foot traffic.