The roof on any commercial building can be an essential part of a business’s plan for success as it provides the first line of defense from the environment. The roof protects the integrity of the building structure, protection to the contents, can contribute to energy efficiency, as well as impact the overall aesthetic appeal of the structure.
Among the various types of commercial roofing systems available, Modified Bitumen stands out for its unique properties and performance advantages.
Modified Bitumen roofing systems are a type of multi-ply roofing, known for their exceptional resilience, and flexibility. Originally developed in Europe in the mid-1960’s and brought to the United States in the late 1970s. Modified Bitumen incorporates the proven characteristics of Built-Up Roofing with the performance features using polymer-modified asphalt to manufacturer membranes with improved elasticity, low-temperature flexibility, and better thermal shock resistance than traditional BUR materials.
Advantages of Modified Bitumen Roofing Systems
Modified Bitumen roofs are constructed with a blend of specialized asphalt, adding plastic or rubber polymers, and specific reinforcement materials that provide a durable roofing product. They incorporate the proven waterproofing characteristics of asphalt and the advanced performance properties of plastic or rubber polymers.
The make-up of a Modified Bitumen roofing system commonly involves two or more layers:
Base Membrane: This first layer, which may be mechanically fastened or bonded depending on the substrate provides the basis for all additional layers of the system. It is generally composed of a tough, glass-fiber or non-woven polyester mat which during manufacturing is saturated and coated with a modified bitumen compound.
Interply Membrane: Depending on the desired durability of the system, often times a second, or interply layer may be used in the roofing system. This layer could be the same as a base membrane or one of many other similar modified bitumen membranes.
Cap Sheet: The surface layer, or the cap sheet, is usually of similar make-up to the base and/or interply layers however often features a surface of mineral granules embedded in the upper modified bitumen for optimal UV protection and aesthetics.
Modified Bitumen roofing systems are available in two common types: SBS (Styrene-Butadiene-Styrene) and APP (Atactic Polypropylene).
SBS Modified Bitumen is known for its rubber-like characteristics and greater flexibility in cold climates. APP Modified Bitumen is recognized for its plastic-like flexibility and greater resistance to high-temperature deformation.
Modified Bitumen Attributes
- Durability: Highly resilient, offering a long life cycle with low maintenance.
- Waterproofing: Superior leak protection due superior polymer- based asphalt composition and redundant layers.
- Versatility: Suitable for various roof styles/sizes and installation methods.
- Energy Efficiency: Highly reflective cap sheet options, reduces cooling load and enhances energy savings.
- Maintainability: Easy to repair and maintain, reducing long-term costs.
Modified Bitumen vs. Single Ply Membranes
These two types of roofing systems have distinctive characteristics, and understanding these differences can help in selecting the right system for a specific roofing project.
Comparative analysis of these two prominent roofing solutions.
EPDM • TPO • PVC – KEE
|Layers of Roof Membrane||2 or more||1|
|Typical Thickness||Up to 300 mils||45 – 90 mils|
|Color Options||11 typical colors||1*|
|Available Surface||Smooth, Granular & Film||Smooth|
|Available Warranties||Up to 30 Years||Up to 30 Years|
|Application Method||Self-Adhered, Heat-Welded, Cold-Applied, Hot Mopped||Fully Adhered (Self-adhered and adhesive adhered), Ballasted, Mechanically-Fastened|
*EPDM is typically black, PVC & TPO are typically white but are available in Gray and Tan
This superiority in application efficiency is not without solid financial evidence. A Polyglass study comparing 2-ply modified bitumen systems and TPO demonstrated a noteworthy trend.
|Labor Cost||Material Cost||Total Job Cost|
|Modified Bitumen Installation||$28,900||$80,700||$109,600|
|Difference (TPO vs. Mod Bit)||+10.4%||+5.11%||+6.5%|
This comparative analysis illustrates the economic advantages of choosing a Modified Bitumen roofing system over a TPO system. Despite the initial cost perception, Modified Bitumen proves to be more cost-efficient in terms of both labor and materials, leading to a lower total job cost.
The Polyglass Advantage: Modified Bitumen and ADESO® Self-Adhered Technology
Polyglass offers some of the industry’s best Modified Bitumen products, with popular offerings including the Elastoflex SA V Plus, Polyfresko G SA, Polyfresko G SBS SA, Polyflex SA P and Elastoflex SA P. Each of these products is designed to provide unmatched durability, weather resistance, and ease of installation.
Highly Reflective Surfaces – Cure Technology
Both Polyfresko G SA and Polyfresko G SBS SA offer a highly reflective factory applied white finished. Patented CURE Technology® sheets have a highly reflective granule surface and it’s a reliable choice for cool roofing systems. In fact, the Polyfresko product offerings demonstrates superior solar reflectivity, with an initial Solar Reflectance Index (SRI) of 96 and a 3-Year Weathered rating of 83, making these products a leader in granule surfaced reflectivity and energy-efficiency.
Highly Reflective SA Cap Sheets
Polyfresko G SA is a self-adhered APP granulated cap sheet designed for low-slope roofing. Polyfresko G SBS SA is a self-adhered SBS granulated cap sheet design for low-sloped roofing. Both offer Polyglass’ patented ADESO® Dual-Compound Self-Adhered Technology, offering durability, excellent tear resistance, and flexibility.
Standard/Colored SA Cap Sheets
Polyflex SA P is an APP granulated cap sheet and Elastoflex SA P is an SBS granulated cap sheet, both offering the same self-adhered technology. These superior SA cap sheets provide robust, flexible, and puncture-resistant roof options for low-slope roofs. Its ease of application and long-term performance make it an efficient choice for modern roofing systems.
SA Base/Interply Membranes
Elastoflex SA V and Elastoflex SA V Plus are self-adhered, SBS membrane products constructed with a high-quality reinforced fiberglass mat for ease of application for low-slope roofing designs.
Like other Polyglass SA membranes, these use the exclusive ADESO® dual-compound self-adhered technology.
Elastoflex SA membranes can used in combination with various self-adhesive cap sheets as well as other approved Polyglass cap sheets. Use of a self-adhesive membrane as a base/interply membrane layer offers a cleaner application process, faster application speed, and a safer option as it eliminates the need for torches, hot asphalt, or bonding adhesives for the initial layer(s) of the roofing system.
ADESO Technology by Polyglass integrates patented innovations like FASTLap® and SEALLap® Ultra, ensuring quick and easy installations while offering customized compound options for diverse roofing needs.
Polyglass advantage is deeply rooted in its commitment to excellence and innovation in modified bitumen roofing products. These products, when used in combination, provide a multi-layered roofing system offering extra protection and peace of mind for your roofing needs.
By harnessing the best qualities of both the polymer and fiberglass reinforcements, Polyglass offers roofing solutions that are truly the best of both worlds.
👉Also read: Polyglass’ Guide to Commercial Roof Installation
A Reliable Partner for Your Commercial Roofing Needs
Polyglass presents an array of high-quality, affordable, and easily installed products, ideal for various low-slope commercial roofing applications.
Beyond delivering superior roofing solutions, Polyglass provides extensive support and training, making sure their systems are applied optimally.
Whether you’re an architect, building owner, contractor, or consultant, Polyglass is prepared to help you tackle your roofing challenges, ensuring a resilient, attractive, and sustainable approach for all your roofing needs now and for the future. Contact us today for more information.