Roofing 101: Types of Commercial Roofing Systems & Principal Components

Commercial Roofing System Foam


As one of the most experienced Los Angeles roofing contractors in the state of California with over 80 years’ experience in the commercial roofing industry, at Stone Roofing we have installed and repaired all types of commercial roofing systems. If you are new to roofing or need a quick overview of the various types of commercial and industrial roofing systems and principal components, we’ve got you covered!

In terms of roofing components, most Los Angeles County and Southern California commercial roofing systems have three principal components:

Weatherproofing layer or layers – the weatherproofing component is the most important element because it keeps water from entering a roof assembly.
Reinforcement – reinforcement adds strength, puncture resistance, and dimensional stability to a membrane.
Surfacing – surfacing is the component that protects the weatherproofing and reinforcement from sunlight and weather. Some surfacing types provide other benefits such as increased fire resistance, improved traffic and hail resistance, and increased solar reflectivity.

Below are five general classifications of commercial roofing systems:

  1. Single-Ply Roofing Membranes including:
    Thermoplastic membranes (e.g., PVC, TPO)
  2. Spray polyurethane foam-based (SPF) roof systems
  3. Metal panel roof systems for low-slope applications
  4. Roof Coatings
  5. Modified Bitumen / Built-Up Roof

Below are the types of California commercial roof surfacing:

Single Ply Roofing

Single ply roofing has become the leading low slope option in commercial and industrial roofing. Single ply roofing benefits include low cost installation, reflectivity, and lack of use of non renewable resources. Single ply roofing is available in a wide variety of types, thickness, colors and installation methods.

  • TPO Roofing
    The fastest growing segment of commercial roofing. TPO membranes are the most economical solution. Seams of the TPO membranes are heat welded together with robotic welders for excellent water tightness.
  • PVC Roofing
    Benefits include great flexibility and excellent chemical resistance. Seams of PVC membranes are heat welded together with robotic welders for water tightness.

California Commercial Roofing Systems Application Methods

  • Mechanically Fasten
    Membrane screws and plates are inserted at the seams of the membrane into the decking substrate.
  • Fully Adhere
    Membrane is attached to the substrate in full coverage of manufacture’s liquid adhesive.
  • Ballast
    Membrane is loose laid and held in place with coverage of ballast rock. Ballast is available in several color options allowing for decorative design options when desired.
  • Rhino Bond
    Specialized plates with membrane coating on top are installed through the substrate. The membrane is laid out on top and attached to the underlying plates with a magnetic welder.

Standing Seam Metal Roofing

A metal panel roof system for low-slope applications, SSMR is available in a wide variety of manufacture’s styles and colors. SSMR is attached to a substrate using hidden clips and has either quick locking or mechanically seamed joints.

Spray Polyurethane Foam-based (SPF) Roof Systems

Polyurethane Spray Foam Roofing Systems provide many benefits to building owners. The two most prominent benefits are waterproofing/leak prevention and insulation value. Many additional benefits also exist such as superior compressive strength, lightweight, self-flashing, durable, and long-lasting.

Benefits of Spray Polyurethane Foam Roof Systems:

  • Leak-free monolithic seal over your entire roof deck
  • Self-flashing
  • High insulation value / Rapid payback with energy savings
    Strong adhesion and wind uplift resistance
  • Weather-resistant
  • Lightweight and high strength
  • UL and FM approved systems
    Sprayed Polyurethane Foam is applied as a liquid using plural-component spray equipment to fill cracks and crevices. It then expands approximately 30 times its original liquid volume to form a hard, closed-cell monolithic roof surface. The Polyurethane Foam dries within seconds after applied to the roof surface. Its expansion results in a weather-tight roofing membrane that is fully adhered to the substrate. Because of polyurethane’s lightweight properties, it adds little additional loads to the structure and is often used in remedial applications. Polyurethane Foam has a history of more than 35 years as a maintainable roofing medium. Polyurethane Foam adds excellent insulation value to the structure and utility bills can reflect the difference.

Built-Up Roofing & Modified Bitumen

Built-Up Roofing consists of multiple piles of roof felts laminated together with bitumen. Built-Up roof material can consist of bitumen-saturated felt, coated felt, polyester felt, or other fabrics. A surfacing is generally applied, including asphalt, aggregate (gravel or slag), emulsion, or a granule-surfaced cap sheet.

Built-Up Roofing is one of the oldest and most reliable ways of installing a new roof. It was first known as composition roofing and started in the 1840’s. B.U.R.’s come in two basic types, asphalt and coal tar, with three basic components:

  1. the waterproofing component
  2. the reinforcing component
  3. the surfacing component which is used to protect the other components from the elements.

The roofing membrane is protected from the elements by a surfacing layer, which can be a cap sheet or gravel embedded in bitumen or a liquid-applied coating material. The most common surface for a BUR system, particularly in the west, is a fiberglass mineral surfaced cap sheet (pictured). The west represents 40 percent of the fiberglass cap sheet market. It has a white granular look, it is cost-effective, and is relatively maintenance-free.

Also known as BUR, this is an asphalt based option that uses flood coats of hot asphalt, ply felt, and gravel surfacing. BUR requires the use of tar kettles and results in significant amounts of fumes during the roofing process.

Modified Bitumen

Modified Bitumen roofing systems create watertight barriers that perform for many years at a time due to the multiple layers of protection. When built up, these layers of bitumen exhibit exceptional resistance to the conductivity of heat between the exterior and interior of the building. This generates a noticeable reduction in heating and cooling costs. The thermoplastic polymers used in the modified bitumen make it more fire-resistant as well. The technology employed in creating this roofing system makes it affordable and easy to generate as well.

Also known as MBR, this is an asphalt-based option that incorporates multiple layers of asphalt sheets attached by one of several options. Types of MBR include SBS and APP

California Commercial Roofing Systems Application Methods

  • Torch Down
    Requires the use of open flame torches to adhere multiple layers together.
  • Cold Applied
    Uses manufacturer’s asphalt based liquid adhesive in full coverage spread to adhere multiple layers together.
  • Hot Applied
    Uses hot tar in full coverage spread to adhere multiple layers together. This has the significant drawback of tar kettle fumes during the installation process

Are You in the Market for a New Commercial Roofing System, Re-Roofing Project or Roofing Repair in Los Angeles County, Southern California or surrounding?

Whether your building is new or old, sloped or flat, large or small, Stone Roofing has the experience and the expertise to cover you.

Using the best materials in the commercial and industrial roofing industry at the most competitive prices around, Stone Roofing will help you pick from one of the best commercial roofing systems to meet your unique needs.

Call us today to book your free, no-obligation on-site roof inspection and estimate. Our highly-skilled, certified commercial roofing contractors are standing by to answer your questions!

Call 1-800-31-STONE

2 thoughts on “Roofing 101: Types of Commercial Roofing Systems & Principal Components

  1. Pingback: Top Considerations for California Commercial Re-Roofing Projects - Stone Roofing - Rock Solid Since 1934

  2. Pingback: Benefits of Modified Bitumen / Built-Up Roofing | Stone Roofing

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