System Types

Not all roofing projects require the same roofing system. Some are certainly better than others and in varying circumstances. Which type should you pick?

Roofing System Types

This is not to identify specific brand or product names, but is meant to provide a brief overview of the various roof system types. There could by many different products or manufacturers used for any given roof system type.

There are generally two roof system classifications from which everything else is specified.

  • Flat or Low-Sloped
  • Steep-Sloped

According to the National Roofing Contractors Association (NRCA), a low-slope roof system is "a category of roof systems that generally includes weatherproof membrane types of roofs systems on slopes at or less than 3:12." That same source says regarding steep-sloped roof systems: "a category of roof systems that generally includes water-shedding types of roof coverage installed on slopes greater than 3:12." (Italics and bold ours.)

So while both system types are to be designed with a proper drainage system in order to get water off the roof as quickly and as reasonably as possible, the basic differences between flat, low-sloped roofing systems and that of steep-sloped roofing systems is two-fold:

  1. Flat and low-sloped roofing systems are geared to be weatherproof and remain relatively flat at a 3:12 pitch or less.
  2. Steep-sloped roofing systems are geared to shed water and remain relatively steep at a pitch of greater than 3:12.

Flat and Low-Sloped Roofing Systems

Depending upon who's counting, it can be reasonably asserted that there are 5 basic types of flat and low-sloped roofing systems.

  • Built-Up Roofs (BUR)
  • Single-Ply Membranes (PVC, TPO, EPDM, etc.)
  • Fluid-Applied
  • Metal
  • Spray Polyurethane Foam (SPF)

Steep-Sloped Roofing Systems

  • Shingles (Asphalt and Wood)
  • Metal
  • Concrete
  • Clay Tile
  • Wood Shakes
  • Slate
  • Synthetic