Commercial Roofing 101 Basic Terminology for Building Owners

Mar 28, 2020Blog, Commercial Roofing

Whether you’re completely new to the world of commercial roofing or it’s simply been a while since your commercial roof has required your attention, you might be a little bit confused by some of the jargon roofing professionals throw around. EPDM, PVC, TPO…What do all those letters even mean anyway?


We want our clients to be completely clear on what they’re getting when they hire River Run Roofing to repair or replace their commercial roof. That’s why we created this quick and easy breakdown of the most important terms and abbreviations you’ll come across during your decision making process.


PVC roofing system


Material Types

Metal: roofing produced from a variety of metal types, including steel, aluminum, stainless steel, copper, and zinc alloys. Learn more about the benefits of metal commercial roofs here.


PVC: polyvinyl chloride, a single-ply roofing membrane made from thermoplastic           material. Learn more about the benefits of PVC commercial roofs here.


TPO: thermoplastic polyolefin, a single-ply roofing membrane composed of polypropylene and ethylene-propylene rubber polymerized together. Learn more about the benefits of TPO commercial roofs here.


EPDM Rubber: ethylene propylene diene terpolymer, a roofing membrane made of synthetic rubber. Learn more about the benefits of EPDM rubber commercial roofs here.


Flexion®: a single-ply PVC roofing membrane created by industry leader Conklin. Learn more about the benefits of Flexion® commercial roofs here.


Commercial Coating: a seamless seal applied over an existing roof for added protection and durability. Learn more about the benefits of commercial roof coatings here.

Other Terminology to Know

Slope or Pitch: the rise of a roof, typically represented by the number of inches of rise for every 12 inches of run (Ex. a 5 pitch roof rises 5 inches for every 12 inches of run).


Low-Slope or Flat Roof: a roof with a slope or pitch of 3 or less.


Reroofing: applying a new roof on top of an existing one (as opposed to removing the existing roof before installing a new one).


Standing Seam: type of metal roof whose panels feature interlocking fasteners concealed by raised seams.


Fully Adhered: a roof that has been applied directly to the insulation below it using adhesives.


Mechanically Attached: a roof that has been applied using a combination of screws and heat-welding.


Ballasted: a roof held in place by a heavy layer of gravel or pavers, instead of adhesives or fasteners.


Heat Island Effect: the rise in temperature typically seen in urban areas caused by tightly spaced buildings and minimal green spaces. The annual mean air temperature of a city with 1 million people or more can be 1.8–5.4°F warmer than nearby suburban or rural areas. In the evening, the difference can jump as high as 22°F. This effect increases energy costs and pollution during warm seasons, along with heat-related illnesses and deaths.