February 13, 2015 : Most Common Commercial Roofing Systems

The Most Common Commercial Roofing Materials

Types of Flat & Low Slope Roof Systems Today

There are currently five basic classifications of commercial roofs that have flat or low slope configurations:

  • Built-Up Roofing
  • Metal Roofing
  • Modified Bitumen Roofing
  • Single-Ply Roofing
  • Spray Polyurethane Foam (SPF roofing)

Built-Up Roofing

Typically referred to as “BUR”, built-up roofs are generally known as “tar and gravel” roofs. In general, they are made up of alternating bitumen layers and reinforcing fabric layers that, together, form finished roofing membranes. These membranes are laid out in cross sections across a building top’s surface. For the most part, built-up roofing is fastened to roof decks and insulation for adherence. The membranes are generally known as plies, but the reinforcement layers have been known to be called “roof felts” or “ply sheets” as well.

Metal Roofing

Metal roofing is one of the most popular choices for commercial roofing today. There are several metal materials which can be used for metal roofing: corrugated galvanized steel, aggregates of zinc, aluminum, and silicon-coated steel, metal tile sheets, stainless steel, copper, aluminum, stone-coated steel, lead, and tin. Because certain kinds of metal roofs, especially steel roofs, can become rusted from prolonged exposure to the sun, these roof types have surfacing layers applied that protect against or resist damaging influences such as sun exposure.

Modified Bitumen Roofing

These roofing systems are composed of reinforcing roof fabrics which function as “carriers” for bitumen, when it is being manufactured into rolls. Similar to BUR membranes, bitumen roofing membranes are installed in layers. They are usually fastened to building tops as two-ply systems that are fully adhered to the roofing deck.

Single-Ply Roofing

Single-ply roofing membranes are factory-made membranes. Generally speaking, there are two kinds of single-ply roofing membranes: thermoplastic membranes, which include PVC and TPO membranes, and thermoset membranes, which include EPDM membranes, a popular rubber roofing system.

SPF Roofing

SPF roofing is foam-based and created by mixing and applying a two-part liquid that serves as this roofing system’s base layer. It can easily be applied with different amounts of thickness for greater R-value, or insulation value, or sloping for drainage.


posted November 18, 2015 by Drew
Good explanation of the different roof types. Metal roofing definitely sounds like the better option but it all depends what your budget can get you. Thanks for sharing.

posted December 22, 2015 by Kyle Ross
This is some great information, and I appreciate your point that metal roofing is a popular choice for commercial purposes. My roof was pretty heavily damaged in a recent storm, and I need to have it replaced soon. I know you said metal roofing is popular commercially, but could it also be a good option for residential purposes? Thanks for the post!

posted January 13, 2016 by Drew Harrison
Metal roofs sound like a really good option for my needs. It sounds like they are stronger and take any potential weather damage well. The area I live in can get some pretty nasty weather and I might need to hire a roofer to get all my options and figure out the best one. Thanks for posting this great info on roofs!

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